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Dr. Carleen Eaton

Dr. Carleen Eaton

The Circulatory System

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Table of Contents

Section 1: Chemistry of Life
Elements, Compounds, and Chemical Bonds

56m 18s

Intro
0:00
Elements
0:09
Elements
0:48
Matter
0:55
Naturally Occurring Elements
1:12
Atomic Number and Atomic Mass
2:39
Compounds
3:06
Molecule
3:07
Compounds
3:14
Examples
3:20
Atoms
4:53
Atoms
4:56
Protons, Neutrons, and Electrons
5:29
Isotopes
10:42
Energy Levels of Electrons
13:01
Electron Shells
13:13
Valence Shell
13:22
Example: Electron Shells and Potential Energy
13:28
Covalent Bonds
19:52
Covalent Bonds
19:54
Examples
20:03
Polar and Nonpolar Covalent Bonds
23:54
Polar Bond
24:07
Nonpolar Bonds
24:17
Examples
24:25
Ionic Bonds
29:04
Ionic Bond, Cations, Anions
29:19
Example: NaCl
29:30
Hydrogen Bond
33:18
Hydrogen Bond
33:20
Chemical Reactions
35:36
Example: Reactants, Products and Chemical Reactions
35:45
Molecular Mass and Molar Concentration
38:45
Avogadro's Number and Mol
39:12
Examples: Molecular Mass and Molarity
42:10
Example 1: Proton, Neutrons and Electrons
47:05
Example 2: Reactants and Products
49:35
Example 3: Bonding
52:39
Example 4: Mass
53:59
Properties of Water

50m 23s

Intro
0:00
Molecular Structure of Water
0:21
Molecular Structure of Water
0:27
Properties of Water
4:30
Cohesive
4:55
Transpiration
5:29
Adhesion
6:20
Surface Tension
7:17
Properties of Water, cont.
9:14
Specific Heat
9:25
High Heat Capacity
13:24
High Heat of Evaporation
16:42
Water as a Solvent
21:13
Solution
21:28
Solvent
21:48
Example: Water as a Solvent
22:22
Acids and Bases
25:40
Example
25:41
pH
36:30
pH Scale: Acidic, Neutral, and Basic
36:35
Example 1: Molecular Structure and Properties of Water
41:18
Example 2: Special Properties of Water
42:53
Example 3: pH Scale
44:46
Example 4: Acids and Bases
46:19
Organic Compounds

53m 54s

Intro
0:00
Organic Compounds
0:09
Organic Compounds
0:11
Inorganic Compounds
0:15
Examples: Organic Compounds
1:15
Isomers
5:52
Isomers
5:55
Structural Isomers
6:23
Geometric Isomers
8:14
Enantiomers
9:55
Functional Groups
12:46
Examples: Functional Groups
12:59
Amino Group
13:51
Carboxyl Group
14:38
Hydroxyl Group
15:22
Methyl Group
16:14
Carbonyl Group
16:30
Phosphate Group
17:51
Carbohydrates
18:26
Carbohydrates
19:07
Example: Monosaccharides
21:12
Carbohydrates, cont.
24:11
Disaccharides, Polysaccharides and Examples
24:21
Lipids
35:52
Examples of Lipids
36:04
Saturated and Unsaturated
38:57
Phospholipids
43:26
Phospholipids
43:29
Example
43:34
Steroids
46:24
Cholesterol
46:28
Example 1: Isomers
48:11
Example 2: Functional Groups
50:45
Example 3: Galactose, Ketose, and Aldehyde Sugar
52:24
Example 4: Class of Molecules
53:06
Nucleic Acids and Proteins

37m 23s

Intro
0:00
Nucleic Acids
0:09
Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA)
0:29
Nucleic Acids, cont.
2:56
Purines
3:10
Pyrimidines
3:32
Double Helix
4:59
Double Helix and Example
5:01
Proteins
12:33
Amino Acids and Polypeptides
12:39
Examples: Amino Acid
13:25
Polypeptide Formation
18:09
Peptide Bonds
18:14
Primary Structure
18:35
Protein Structure
23:19
Secondary Structure
23:22
Alpha Helices and Beta Pleated Sheets
23:34
Protein Structure
25:43
Tertiary Structure
25:44
5 Types of Interaction
26:56
Example 1: Complementary DNA Strand
31:45
Example 2: Differences Between DNA and RNA
33:19
Example 3: Amino Acids
34:32
Example 4: Tertiary Structure of Protein
35:46
Section 2: Cell Structure and Function
Cell Types (Prokaryotic and Eukaryotic)

45m 50s

Intro
0:00
Cell Theory and Cell Types
0:12
Cell Theory
0:13
Prokaryotic and Eukaryotic Cells
0:36
Endosymbiotic Theory
1:13
Study of Cells
4:07
Tools and Techniques
4:08
Light Microscopes
5:08
Light vs. Electron Microscopes: Magnification
5:18
Light vs. Electron Microscopes: Resolution
6:26
Light vs. Electron Microscopes: Specimens
7:53
Electron Microscopes: Transmission and Scanning
8:28
Cell Fractionation
10:01
Cell Fractionation Step 1: Homogenization
10:33
Cell Fractionation Step 2: Spin
11:24
Cell Fractionation Step 3: Differential Centrifugation
11:53
Comparison of Prokaryotic and Eukaryotic Cells
14:12
Prokaryotic vs. Eukaryotic Cells: Domains
14:43
Prokaryotic vs. Eukaryotic Cells: Plasma Membrane
15:40
Prokaryotic vs. Eukaryotic Cells: Cell Walls
16:15
Prokaryotic vs. Eukaryotic Cells: Genetic Materials
16:38
Prokaryotic vs. Eukaryotic Cells: Structures
17:28
Prokaryotic vs. Eukaryotic Cells: Unicellular and Multicellular
18:19
Prokaryotic vs. Eukaryotic Cells: Size
18:31
Plasmids
18:52
Prokaryotic vs. Eukaryotic Cells
19:22
Nucleus
19:24
Organelles
19:48
Cytoskeleton
20:02
Cell Wall
20:35
Ribosomes
20:57
Size
21:37
Comparison of Plant and Animal Cells
22:15
Plasma Membrane
22:55
Plant Cells Only: Cell Walls
23:12
Plant Cells Only: Central Vacuole
25:08
Animal Cells Only: Centrioles
26:40
Animal Cells Only: Lysosomes
27:43
Plant vs. Animal Cells
29:16
Overview of Plant and Animal Cells
29:17
Evidence for the Endosymbiotic Theory
30:52
Characteristics of Mitochondria and Chloroplasts
30:54
Example 1: Prokaryotic vs. Eukaryotic Cells
35:44
Example 2: Endosymbiotic Theory and Evidence
38:38
Example 3: Plant and Animal Cells
41:49
Example 4: Cell Fractionation
43:44
Subcellular Structure

59m 38s

Intro
0:00
Prokaryotic Cells
0:09
Shapes of Prokaryotic Cells
0:22
Cell Wall
1:19
Capsule
3:23
Pili/Fimbria
3:54
Flagella
4:35
Nucleoid
6:16
Plasmid
6:37
Ribosomes
7:09
Eukaryotic Cells (Animal Cell Structure)
8:01
Plasma Membrane
8:13
Microvilli
8:48
Nucleus
9:47
Nucleolus
11:06
Ribosomes: Free and Bound
12:26
Rough Endoplasmic Reticulum (RER)
13:43
Eukaryotic Cells (Animal Cell Structure), cont.
14:51
Endoplasmic Reticulum: Smooth and Rough
15:08
Golgi Apparatus
17:55
Vacuole
20:43
Lysosome
22:01
Mitochondria
25:40
Peroxisomes
28:18
Cytoskeleton
30:41
Cytoplasm and Cytosol
30:53
Microtubules: Centrioles, Spindel Fibers, Clagell, Cillia
32:06
Microfilaments
36:39
Intermediate Filaments and Kerotin
38:52
Eukaryotic Cells (Plant Cell Structure)
40:08
Plasma Membrane, Primary Cell Wall, and Secondary Cell Wall
40:30
Middle Lamella
43:21
Central Cauole
44:12
Plastids: Leucoplasts, Chromoplasts, Chrloroplasts
45:35
Chloroplasts
47:06
Example 1: Structures and Functions
48:46
Example 2: Cell Walls
51:19
Example 3: Cytoskeleton
52:53
Example 4: Antibiotics and the Endosymbiosis Theory
56:55
Cell Membranes and Transport

53m 10s

Intro
0:00
Cell Membrane Structure
0:09
Phospholipids Bilayer
0:11
Chemical Structure: Amphipathic and Fatty Acids
0:25
Cell Membrane Proteins
2:44
Fluid Mosaic Model
2:45
Peripheral Proteins and Integral Proteins
3:19
Transmembrane Proteins
4:34
Cholesterol
4:48
Functions of Membrane Proteins
6:39
Transport Across Cell Membranes
9:52
Transport Across Cell Membranes
9:53
Methods of Passive Transport
12:07
Passive and Active Transport
12:08
Simple Diffusion
12:45
Facilitated Diffusion
15:20
Osmosis
17:17
Definition and Example of Osmosis
17:18
Hypertonic, Hypotonic, and Isotonic
21:47
Active Transport
27:57
Active Transport
28:17
Sodium and Potassium Pump
29:45
Cotransport
34:38
2 Types of Active Transport
37:09
Endocytosis and Exocytosis
37:38
Endocytosis and Exocytosis
37:51
Types of Endocytosis: Pinocytosis
40:39
Types of Endocytosis: Phagocytosis
41:02
Receptor Mediated Endocytosis
41:27
Receptor Mediated Endocytosis
41:28
Example 1: Cell Membrane and Permeable Substances
43:59
Example 2: Osmosis
45:20
Example 3: Active Transport, Cotransport, Simple and Facilitated Diffusion
47:36
Example 4: Match Terms with Definition
50:55
Cellular Communication

57m 9s

Intro
0:00
Extracellular Matrix
0:28
The Extracellular Matrix (ECM)
0:29
ECM in Animal Cells
0:55
Fibronectin and Integrins
1:34
Intercellular Communication in Plants
2:48
Intercellular Communication in Plants: Plasmodesmata
2:50
Cell to Cell Communication in Animal Cells
3:39
Cell Junctions
3:42
Desmosomes
3:54
Tight Junctions
5:07
Gap Junctions
7:00
Cell Signaling
8:17
Cell Signaling: Ligand and Signal Transduction Pathway
8:18
Direct Contact
8:48
Over Distances Contact and Hormones
10:09
Stages of Cell Signaling
11:53
Reception Phase
11:54
Transduction Phase
13:49
Response Phase
14:45
Cell Membrane Receptors
15:37
G-Protein Coupled Receptor
15:38
Cell Membrane Receptor, Cont.
21:37
Receptor Tyrosine Kinases (RTKs)
21:38
Autophosphorylation, Monomer, and Dimer
22:57
Cell Membrane Receptor, Cont.
27:01
Ligand-Gated Ion Channels
27:02
Intracellular Receptors
29:43
Intracellular Receptor and Receptor -Ligand Complex
29:44
Signal Transduction
32:57
Signal Transduction Pathways
32:58
Adenylyl Cyclase and cAMP
35:53
Second Messengers
39:18
cGMP, Inositol Trisphosphate, and Diacylglycerol
39:20
Cell Response
45:15
Cell Response
45:16
Apoptosis
46:57
Example 1: Tight Junction and Gap Junction
48:29
Example 2: Three Phases of Cell Signaling
51:48
Example 3: Ligands and Binding of Hormone
54:03
Example 4: Signal Transduction
56:06
Section 3: Cell Division
The Cell Cycle

37m 49s

Intro
0:00
Functions of Cell Division
0:09
Overview of Cell Division: Reproduction, Growth, and Repair
0:11
Important Term: Daughter Cells
2:25
Chromosome Structure
3:36
Chromosome Structure: Sister Chromatids and Centromere
3:37
Chromosome Structure: Chromatin
4:31
Chromosome with One Chromatid or Two Chromatids
5:25
Chromosome Structure: Long and Short Arm
6:49
Mitosis and Meiosis
7:00
Mitosis
7:41
Meiosis
8:40
The Cell Cycle
10:43
Mitotic Phase and Interphase
10:44
Cytokinesis
15:51
Cytokinesis in Animal Cell: Cleavage Furrow
15:52
Cytokinesis in Plant Cell: Cell Plate
17:28
Control of the Cell Cycle
18:28
Cell Cycle Control System and Checkpoints
18:29
Cyclins and Cyclin Dependent Kinases
21:18
Cyclins and Cyclin Dependent Kinases (CDKSs)
21:20
MPF
23:17
Internal Factor Regulating Cell Cycle
24:00
External Factor Regulating Cell Cycle
24:53
Contact Inhibition and Anchorage Dependent
25:53
Cancer and the Cell Cycle
27:42
Cancer Cells
27:46
Example1: Parts of the Chromosome
30:15
Example 2: Cell Cycle
31:50
Example 3: Control of the Cell Cycle
33:32
Example 4: Cancer and the Cell
35:01
Mitosis

35m 1s

Intro
0:00
Review of the Cell Cycle
0:09
Interphase: G1 Phase
0:34
Interphase: S Phase
0:56
Interphase: G2 Phase
1:31
M Phase: Mitosis and Cytokinesis
1:47
Overview of Mitosis
3:08
What is Mitosis?
3:10
Overview of Mitosis
3:17
Diploid and Haploid
5:37
Homologous Chromosomes
6:04
The Spindle Apparatus
11:57
The Spindle Apparatus
12:00
Centrosomes and Centrioles
12:40
Microtubule Organizing Center
13:03
Spindle Fiber of Spindle Microtubules
13:23
Kinetochores
14:06
Asters
15:45
Prophase
16:47
First Phase of Mitosis: Prophase
16:54
Metaphase
20:05
Second Phase of Mitosis: Metaphase
20:10
Anaphase
22:52
Third Phase of Mitosis: Anaphase
22:53
Telophase and Cytokinesis
24:34
Last Phase of Mitosis: Telophase and Cytokinesis
24:35
Summary of Mitosis
27:46
Summary of Mitosis
27:47
Example 1: Spindle Apparatus
28:50
Example 2: Last Phase of Mitosis
30:39
Example 3: Prophase
32:41
Example 4: Identify the Phase
33:52
Meiosis

1h 58s

Intro
0:00
Haploid and Diploid Cells
0:09
Diploid and Somatic Cells
0:29
Haploid and Gametes
1:20
Example: Human Cells and Chromosomes
1:41
Sex Chromosomes
6:00
Comparison of Mitosis and Meiosis
10:42
Mitosis Vs. Meiosis: Cell Division
10:59
Mitosis Vs. Meiosis: Daughter Cells
12:31
Meiosis: Pairing of Homologous Chromosomes
13:40
Mitosis and Meiosis
14:21
Process of Mitosis
14:27
Process of Meiosis
16:12
Synapsis and Crossing Over
19:14
Prophase I: Synapsis and Crossing Over
19:15
Chiasmata
22:33
Meiosis I
25:49
Prophase I: Crossing Over
25:50
Metaphase I: Homologs Line Up
26:00
Anaphase I: Homologs Separate
28:16
Telophase I and Cytokinesis
29:15
Independent Assortment
30:58
Meiosis II
32:17
Propphase II
33:50
Metaphase II
34:06
Anaphase II
34:50
Telophase II
36:09
Cytokinesis
37:00
Summary of Meiosis
38:15
Summary of Meiosis
38:16
Cell Division Mechanism in Plants
41:57
Example 1: Cell Division and Meiosis
46:15
Example 2: Phases of Meiosis
50:22
Example 3: Label the Figure
54:29
Example 4: Four Differences Between Mitosis and Meiosis
56:37
Section 4: Cellular Energetics
Enzymes

51m 3s

Intro
0:00
Law of Thermodynamics
0:08
Thermodynamics
0:09
The First Law of Thermodynamics
0:37
The Second Law of Thermodynamics
1:24
Entropy
1:35
The Gibbs Free Energy Equation
3:07
The Gibbs Free Energy Equation
3:08
ATP
8:23
Adenosine Triphosphate (ATP)
8:24
Cellular Respiration
11:32
Catabolic Pathways
12:28
Anabolic Pathways
12:54
Enzymes
14:31
Enzymes
14:32
Enzymes and Exergonic Reaction
14:40
Enzymes and Endergonic Reaction
16:36
Enzyme Specificity
21:29
Substrate
21:41
Induced Fit
23:04
Factors Affecting Enzyme Activity
25:55
Substrate Concentration
26:07
pH
27:10
Temperature
29:14
Presence of Cofactors
29:57
Regulation of Enzyme Activity
31:12
Competitive Inhibitors
32:13
Noncompetitive Inhibitors
33:52
Feedback Inhibition
35:22
Allosteric Interactions
36:56
Allosteric Regulators
37:00
Example 1: Is the Inhibitor Competitive or Noncompetitive?
40:49
Example 2: Thermophiles
44:18
Example 3: Exergonic or Endergonic
46:09
Example 4: Energy Vs. Reaction Progress Graph
48:47
Glycolysis and Anaerobic Respiration

38m 1s

Intro
0:00
Cellular Respiration Overview
0:13
Cellular Respiration
0:14
Anaerobic Respiration vs. Aerobic Respiration
3:50
Glycolysis Overview
4:48
Overview of Glycolysis
4:50
Glycolysis Involves a Redox Reaction
7:02
Redox Reaction
7:04
Glycolysis
15:04
Important Facts About Glycolysis
15:07
Energy Invested Phase
16:12
Splitting of Fructose 1,6-Phosphate and Energy Payoff Phase
17:50
Substrate Level Phophorylation
22:12
Aerobic Versus Anaerobic Respiration
23:57
Aerobic Versus Anaerobic Respiration
23:58
Cellular Respiration Overview
27:15
When Cellular Respiration is Anaerobic
27:17
Glycolysis
28:26
Alcohol Fermentation
28:45
Lactic Acid Fermentation
29:58
Example 1: Glycolysis
31:04
Example 2: Glycolysis, Fermentation and Anaerobic Respiration
33:44
Example 3: Aerobic Respiration Vs. Anaerobic Respiration
35:25
Example 4: Exergonic Reaction and Endergonic Reaction
36:42
Aerobic Respiration

51m 6s

Intro
0:00
Aerobic Vs. Anaerobic Respiration
0:06
Aerobic and Anaerobic Comparison
0:07
Review of Glycolysis
1:48
Overview of Glycolysis
2:06
Glycolysis: Energy Investment Phase
2:25
Glycolysis: Energy Payoff Phase
2:58
Conversion of Pyruvate to Acetyl CoA
4:55
Conversion of Pyruvate to Acetyl CoA
4:56
Energy Formation
8:06
Mitochondrial Structure
8:58
Endosymbiosis Theory
9:23
Matrix
10:00
Outer Membrane, Inner Membrane, and Intermembrane Space
10:43
Cristae
11:47
The Citric Acid Cycle
12:11
The Citric Acid Cycle (Also Called Krebs Cycle)
12:12
Substrate Level Phosphorylation
18:47
Summary of ATP, NADH, and FADH2 Production
23:13
Process: Glycolysis
23:28
Process: Acetyl CoA Production
23:36
Process: Citric Acid Cycle
23:52
The Electron Transport Chain
24:24
Oxidative Phosphorylation
24:28
The Electron Transport Chain and ATP Synthase
25:20
Carrier Molecules: Cytochromes
27:18
Carrier Molecules: Flavin Mononucleotide (FMN)
28:05
Chemiosmosis
32:46
The Process of Chemiosmosis
32:47
Summary of ATP Produced by Aerobic Respiration
38:24
ATP Produced by Aerobic Respiration
38:27
Example 1: Aerobic Respiration
43:38
Example 2: Label the Location for Each Process and Structure
45:08
Example 3: The Electron Transport Chain
47:06
Example 4: Mitochondrial Inner Membrane
48:38
Photosynthesis

1h 2m 52s

Intro
0:00
Photosynthesis
0:09
Introduction to Photosynthesis
0:10
Autotrophs and Heterotrophs
0:25
Overview of Photosynthesis Reaction
1:05
Leaf Anatomy and Chloroplast Structure
2:54
Chloroplast
2:55
Cuticle
3:16
Upper Epidermis
3:27
Mesophyll
3:40
Stomates
4:00
Guard Cells
4:45
Transpiration
5:01
Vascular Bundle
5:20
Stroma and Double Membrane
6:20
Grana
7:17
Thylakoids
7:30
Dark Reaction and Light Reaction
7:46
Light Reactions
8:43
Light Reactions
8:47
Pigments: Chlorophyll a, Chlorophyll b, and Carotenoids
9:19
Wave and Particle
12:10
Photon
12:34
Photosystems
13:24
Photosystems
13:28
Reaction-Center Complex and Light Harvesting Complexes
14:01
Noncyclic Photophosphorylation
17:46
Noncyclic Photophosphorylation Overview
17:47
What is Photophosphorylation?
18:25
Noncyclic Photophosphorylation Process
19:07
Photolysis and The Rest of Noncyclic Photophosphorylation
21:33
Cyclic Photophosphorylation
31:45
Cyclic Photophosphorylation
31:46
Light Independent Reactions
34:34
The Calvin Cycle
34:35
C3 Plants and Photorespiration
40:31
C3 Plants and Photorespiration
40:32
C4 Plants
45:32
C4 Plants: Structures and Functions
45:33
CAM Plants
50:25
CAM Plants: Structures and Functions
50:35
Example 1: Calvin Cycle
54:34
Example 2: C4 Plant
55:48
Example 3: Photosynthesis and Photorespiration
58:35
Example 4: CAM Plants
1:00:41
Section 5: Molecular Genetics
DNA Synthesis

38m 45s

Intro
0:00
Review of DNA Structure
0:09
DNA Molecules
0:10
Nitrogenous Base: Pyrimidines and Purines
1:25
DNA Double Helix
3:03
Complementary Strands of DNA
3:12
5' to 3' & Antiparallel
4:55
Overview of DNA Replication
7:10
DNA Replication & Semiconservative
7:11
DNA Replication
10:26
Origin of Replication
10:28
Helicase
11:10
Single-Strand Binding Protein
12:05
Topoisomerases
13:14
DNA Polymerase
14:26
Primase
15:55
Leading and Lagging Strands
16:51
Leading Strand and Lagging Strand
16:52
Okazaki Fragments
18:10
DNA Polymerase I
20:11
Ligase
21:12
Proofreading and Mismatch Repair
22:18
Proofreading
22:19
Mismatch
23:33
Telomeres
24:58
Telomeres
24:59
Example 1: Function of Enzymes During DNA Synthesis
28:09
Example 2: Accuracy of the DNA Sequence
31:42
Example 3: Leading Strand and Lagging Strand
32:38
Example 4: Telomeres
35:40
Transcription and Translation

1h 17m 1s

Intro
0:00
Transcription and Translation Overview
0:07
From DNA to RNA to Protein
0:09
Structure and Types of RNA
3:14
Structure and Types of RNA
3:33
mRNA
6:19
rRNA
7:02
tRNA
7:28
Transcription
7:54
Initiation Phase
8:11
Elongation Phase
12:12
Termination Phase
14:51
RNA Processing
16:11
Types of RNA Processing
16:12
Exons and Introns
16:35
Splicing & Spliceosomes
18:27
Addition of a 5' Cap and a Poly A tail
20:41
Alternative Splicing
21:43
Translation
23:41
Nucleotide Triplets or Codons
23:42
Start Codon
25:24
Stop Codons
25:38
Coding of Amino Acids and Wobble Position
25:57
Translation Cont.
28:29
Transfer RNA (tRNA): Structures and Functions
28:30
Ribosomes
35:15
Peptidyl, Aminoacyl, and Exit Site
35:23
Steps of Translation
36:58
Initiation Phase
37:12
Elongation Phase
43:12
Termination Phase
45:28
Mutations
49:43
Types of Mutations
49:44
Substitutions: Silent
51:11
Substitutions: Missense
55:27
Substitutions: Nonsense
59:37
Insertions and Deletions
1:01:10
Example 1: Three Types of Processing that are Performed on pre-mRNA
1:06:53
Example 2: The Process of Translation
1:09:10
Example 3: Transcription
1:12:04
Example 4: Three Types of Substitution Mutations
1:14:09
Viral Structure and Genetics

43m 12s

Intro
0:00
Structure of Viruses
0:09
Structure of Viruses: Capsid and Envelope
0:10
Bacteriophage
1:48
Other Viruses
2:28
Overview of Viral Reproduction
3:15
Host Range
3:48
Step 1: Bind to Host Cell
4:39
Step 2: Viral Nuclei Acids Enter the Cell
5:15
Step 3: Viral Nucleic Acids & Proteins are Synthesized
5:54
Step 4: Virus Assembles
6:34
Step 5: Virus Exits the Cell
6:55
The Lytic Cycle
7:37
Steps in the Lytic Cycle
7:38
The Lysogenic Cycle
11:27
Temperate Phage
11:34
Steps in the Lysogenic Cycle
12:09
RNA Viruses
16:57
Types of RNA Viruses
17:15
Positive Sense
18:16
Negative Sense
18:48
Reproductive Cycle of RNA Viruses
19:32
Retroviruses
25:48
Complementary DNA (cDNA) & Reverse Transcriptase
25:49
Life Cycle of a Retrovirus
28:22
Prions
32:42
Prions: Definition and Examples
32:45
Viroids
34:46
Example 1: The Lytic Cycle
35:37
Example 2: Retrovirus
38:03
Example 3: Positive Sense RNA vs. Negative Sense RNA
39:10
Example 4: The Lysogenic Cycle
40:42
Bacterial Genetics and Gene Regulation

49m 45s

Intro
0:00
Bacterial Genomes
0:09
Structure of Bacterial Genomes
0:16
Transformation
1:22
Transformation
1:23
Vector
2:49
Transduction
3:32
Process of Transduction
3:38
Conjugation
8:06
Conjugation & F factor
8:07
Operons
14:02
Definition and Example of Operon
14:52
Structural Genes
16:23
Promoter Region
17:04
Regulatory Protein & Operators
17:53
The lac Operon
20:09
The lac Operon: Inducible System
20:10
The trp Operon
28:02
The trp Operon: Repressible System
28:03
Corepressor
31:37
Anabolic & Catabolic
33:12
Positive Regulation of the lac Operon
34:39
Positive Regulation of the lac Operon
34:40
Example 1: The Process of Transformation
39:07
Example 2: Operon & Terms
43:29
Example 3: Inducible lac Operon and Repressible trp Operon
45:15
Example 4: lac Operon
47:10
Eukaryotic Gene Regulation and Mobile Genetic Elements

54m 26s

Intro
0:00
Mechanism of Gene Regulation
0:11
Differential Gene Expression
0:13
Levels of Regulation
2:24
Chromatin Structure and Modification
4:35
Chromatin Structure
4:36
Levels of Packing
5:50
Euchromatin and Heterochromatin
8:58
Modification of Chromatin Structure
9:58
Epigenetic
12:49
Regulation of Transcription
14:20
Promoter Region, Exon, and Intron
14:26
Enhancers: Control Element
15:31
Enhancer & DNA-Bending Protein
17:25
Coordinate Control
21:23
Silencers
23:01
Post-Transcriptional Regulation
24:05
Post-Transcriptional Regulation
24:07
Alternative Splicing
27:19
Differences in mRNA Stability
28:02
Non-Coding RNA Molecules: micro RNA & siRNA
30:01
Regulation of Translation and Post-Translational Modifications
32:31
Regulation of Translation and Post-Translational Modifications
32:55
Ubiquitin
35:21
Proteosomes
36:04
Transposons
37:50
Mobile Genetic Elements
37:56
Barbara McClintock
38:37
Transposons & Retrotransposons
40:38
Insertion Sequences
43:14
Complex Transposons
43:58
Example 1: Four Mechanisms that Decrease Production of Protein
45:13
Example 2: Enhancers and Gene Expression
49:09
Example 3: Primary Transcript
50:41
Example 4: Retroviruses and Retrotransposons
52:11
Biotechnology

49m 26s

Intro
0:00
Definition of Biotechnology
0:08
Biotechnology
0:09
Genetic Engineering
1:05
Example: Golden Corn
1:57
Recombinant DNA
2:41
Recombinant DNA
2:42
Transformation
3:24
Transduction
4:24
Restriction Enzymes, Restriction Sites, & DNA Ligase
5:32
Gene Cloning
13:48
Plasmids
14:20
Gene Cloning: Step 1
17:35
Gene Cloning: Step 2
17:57
Gene Cloning: Step 3
18:53
Gene Cloning: Step 4
19:46
Gel Electrophoresis
27:25
What is Gel Electrophoresis?
27:26
Gel Electrophoresis: Step 1
28:13
Gel Electrophoresis: Step 2
28:24
Gel Electrophoresis: Step 3 & 4
28:39
Gel Electrophoresis: Step 5
29:55
Southern Blotting
31:25
Polymerase Chain Reaction (PCR)
32:11
Polymerase Chain Reaction (PCR)
32:12
Denaturing Phase
35:40
Annealing Phase
36:07
Elongation/ Extension Phase
37:06
DNA Sequencing and the Human Genome Project
39:19
DNA Sequencing and the Human Genome Project
39:20
Example 1: Gene Cloning
40:40
Example 2: Recombinant DNA
43:04
Example 3: Match Terms With Descriptions
45:43
Example 4: Polymerase Chain Reaction
47:36
Section 6: Heredity
Mendelian Genetics

1h 32m 8s

Intro
0:00
Background
0:40
Gregory Mendel & Mendel's Law
0:41
Blending Hypothesis
1:04
Particulate Inheritance
2:08
Terminology
2:55
Gene
3:05
Locus
3:57
Allele
4:37
Dominant Allele
5:48
Recessive Allele
7:38
Genotype
9:22
Phenotype
10:01
Homozygous
10:44
Heterozygous
11:39
Penetrance
11:57
Expressivity
14:15
Mendel's Experiments
15:31
Mendel's Experiments: Pea Plants
15:32
The Law of Segregation
21:16
Mendel's Conclusions
21:17
The Law of Segregation
22:57
Punnett Squares
28:27
Using Punnet Squares
28:30
The Law of Independent Assortment
32:35
Monohybrid
32:38
Dihybrid
33:29
The Law of Independent Assortment
34:00
The Law of Independent Assortment, cont.
38:13
The Law of Independent Assortment: Punnet Squares
38:29
Meiosis and Mendel's Laws
43:38
Meiosis and Mendel's Laws
43:39
Test Crosses
49:07
Test Crosses Example
49:08
Probability: Multiplication Rule and the Addition Rule
53:39
Probability Overview
53:40
Independent Events & Multiplication Rule
55:40
Mutually Exclusive Events & Addition Rule
1:00:25
Incomplete Dominance, Codominance and Multiple Alleles
1:02:55
Incomplete Dominance
1:02:56
Incomplete Dominance, Codominance and Multiple Alleles
1:07:06
Codominance and Multiple Alleles
1:07:08
Polygenic Inheritance and Pleoitropy
1:10:19
Polygenic Inheritance and Pleoitropy
1:10:26
Epistasis
1:12:51
Example of Epistasis
1:12:52
Example 1: Genetic of Eye Color and Height
1:17:39
Example 2: Blood Type
1:21:57
Example 3: Pea Plants
1:25:09
Example 4: Coat Color
1:28:34
Linked Genes and Non-Mendelian Modes of Inheritance

39m 38s

Intro
0:00
Review of the Law of Independent Assortment
0:14
Review of the Law of Independent Assortment
0:24
Linked Genes
6:06
Linked Genes
6:07
Bateson & Pannett: Pea Plants
8:00
Crossing Over and Recombination
15:17
Crossing Over and Recombination
15:18
Extranuclear Genes
20:50
Extranuclear Genes
20:51
Cytoplasmic Genes
21:31
Genomic Imprinting
23:45
Genomic Imprinting
23:58
Methylation
24:43
Example 1: Recombination Frequencies & Linkage Map
27:07
Example 2: Linked Genes
28:39
Example 3: Match Terms to Correct Descriptions
36:46
Example 4: Leber's Optic Neuropathy
38:40
Sex-Linked Traits and Pedigree Analysis

43m 39s

Intro
0:00
Sex-Linked Traits
0:09
Human Chromosomes, XY, and XX
0:10
Thomas Morgan's Drosophila
1:44
X-Inactivation and Barr Bodies
14:48
X-Inactivation Overview
14:49
Calico Cats Example
17:04
Pedigrees
19:24
Definition and Example of Pedigree
19:25
Autosomal Dominant Inheritance
20:51
Example: Huntington's Disease
20:52
Autosomal Recessive Inheritance
23:04
Example: Cystic Fibrosis, Tay-Sachs Disease, and Phenylketonuria
23:05
X-Linked Recessive Inheritance
27:06
Example: Hemophilia, Duchene Muscular Dystrohpy, and Color Blindess
27:07
Example 1: Colorblind
29:48
Example 2: Pedigree
37:07
Example 3: Inheritance Pattern
39:54
Example 4: X-inactivation
41:17
Section 7: Evolution
Natural Selection

1h 3m 28s

Intro
0:00
Background
0:09
Work of Other Scientists
0:15
Aristotle
0:43
Carl Linnaeus
1:32
George Cuvier
2:47
James Hutton
4:10
Thomas Malthus
5:05
Jean-Baptiste Lamark
5:45
Darwin's Theory of Natural Selection
7:50
Evolution
8:00
Natural Selection
8:43
Charles Darwin & The Galapagos Islands
10:20
Genetic Variation
20:37
Mutations
20:38
Independent Assortment
21:04
Crossing Over
24:40
Random Fertilization
25:26
Natural Selection and the Peppered Moth
26:37
Natural Selection and the Peppered Moth
26:38
Types of Natural Selection
29:52
Directional Selection
29:55
Stabilizing Selection
32:43
Disruptive Selection
34:21
Sexual Selection
36:18
Sexual Dimorphism
37:30
Intersexual Selection
37:57
Intrasexual Selection
39:20
Evidence for Evolution
40:55
Paleontology: Fossil Record
41:30
Biogeography
45:35
Continental Drift
46:06
Pangaea
46:28
Marsupials
47:11
Homologous and Analogous Structure
50:10
Homologous Structure
50:12
Analogous Structure
53:21
Example 1: Genetic Variation & Natural Selection
56:15
Example 2: Types of Natural Selection
58:07
Example 3: Mechanisms By Which Genetic Variation is Maintained Within a Population
1:00:12
Example 4: Difference Between Homologous and Analogous Structures
1:01:28
Population Genetic and Evolution

53m 22s

Intro
0:00
Review of Natural Selection
0:12
Review of Natural Selection
0:13
Genetic Drift and Gene Flow
4:40
Definition of Genetic Drift
4:41
Example of Genetic Drift: Cholera Epidemic
5:15
Genetic Drift: Founder Effect
7:28
Genetic Drift: Bottleneck Effect
10:27
Gene Flow
13:00
Quantifying Genetic Variation
14:32
Average Heterozygosity
15:08
Nucleotide Variation
17:05
Maintaining Genetic Variation
18:12
Heterozygote Advantage
19:45
Example of Heterozygote Advantage: Sickle Cell Anemia
20:21
Diploidy
23:44
Geographic Variation
26:54
Frequency Dependent Selection and Outbreeding
28:15
Neutral Traits
30:55
The Hardy-Weinberg Equilibrium
31:11
The Hardy-Weinberg Equilibrium
31:49
The Hardy-Weinberg Conditions
32:42
The Hardy-Weinberg Equation
34:05
The Hardy-Weinberg Example
36:33
Example 1: Match Terms to Descriptions
42:28
Example 2: The Hardy-Weinberg Equilibrium
44:31
Example 3: The Hardy-Weinberg Equilibrium
49:10
Example 4: Maintaining Genetic Variation
51:30
Speciation and Patterns of Evolution

51m 2s

Intro
0:00
Early Life on Earth
0:08
Early Earth
0:09
1920's Oparin & Haldane
0:58
Abiogenesis
2:15
1950's Miller & Urey
2:45
Ribozymes
5:34
3.5 Billion Years Ago
6:39
2.5 Billion Years Ago
7:14
1.5 Billion Years Ago
7:41
Endosymbiosis
8:00
540 Million Years Ago: Cambrian Explosion
9:57
Gradualism and Punctuated Equilibrium
11:46
Gradualism
11:47
Punctuated Equilibrium
12:45
Adaptive Radiation
15:08
Adaptive Radiation
15:09
Example of Adaptive Radiation: Galapogos Islands
17:11
Convergent Evolution, Divergent Evolution, and Coevolution
18:30
Convergent Evolution
18:39
Divergent Evolution
21:30
Coevolution
23:49
Speciation
26:27
Definition and Example of Species
26:29
Reproductive Isolation: Prezygotive
27:49
Reproductive Isolation: Post zygotic
29:28
Allopatric Speciation
30:21
Allopatric Speciation & Geographic Isolation
30:28
Genetic Drift
31:31
Sympatric Speciation
34:10
Sympatric Speciation
34:11
Polyploidy & Autopolyploidy
35:12
Habitat Isolation
39:17
Temporal Isolation
41:27
Selection Selection
41:40
Example 1: Pattern of Evolution
42:53
Example 2: Sympatric Speciation
45:16
Example 3: Patterns of Evolution
48:08
Example 4: Patterns of Evolution
49:27
Section 8: Diversity of Life
Classification

1h 51s

Intro
0:00
Systems of Classification
0:07
Taxonomy
0:08
Phylogeny
1:04
Phylogenetics Tree
1:44
Cladistics
3:37
Classification of Organisms
5:31
Example of Carl Linnaeus System
5:32
Domains
9:26
Kingdoms: Monera, Protista, Plantae, Fungi, Animalia
9:27
Monera
10:06
Phylogentics Tree: Eurkarya, Bacteria, Archaea
11:58
Domain Eukarya
12:50
Domain Bacteria
15:43
Domain Bacteria
15:46
Pathogens
16:41
Decomposers
18:00
Domain Archaea
19:43
Extremophiles Archaea: Thermophiles and Halophiles
19:44
Methanogens
20:58
Phototrophs, Autotrophs, Chemotrophs and Heterotrophs
24:40
Phototrophs and Chemotrophs
25:02
Autotrophs and Heterotrophs
26:54
Photoautotrophs
28:50
Photoheterotrophs
29:28
Chemoautotrophs
30:06
Chemoheterotrophs
31:37
Domain Eukarya
32:40
Domain Eukarya
32:43
Plant Kingdom
34:28
Protists
35:48
Fungi Kingdom
37:06
Animal Kingdom
38:35
Body Symmetry
39:25
Lack Symetry
39:40
Radial Symmetry: Sea Aneome
40:15
Bilateral Symmetry
41:55
Cephalization
43:29
Germ Layers
44:54
Diploblastic Animals
45:18
Triploblastic Animals
45:25
Ectoderm
45:36
Endoderm
46:07
Mesoderm
46:41
Coelomates
47:14
Coelom
47:15
Acoelomate
48:22
Pseudocoelomate
48:59
Coelomate
49:31
Protosomes
50:46
Deuterosomes
51:20
Example 1: Domains
53:01
Example 2: Match Terms with Descriptions
56:00
Example 3: Kingdom Monera and Domain Archaea
57:50
Example 4: System of Classification
59:37
Bacteria

36m 46s

Intro
0:00
Comparison of Domain Archaea and Domain Bacteria
0:08
Overview of Archaea and Bacteria
0:09
Archaea vs. Bacteria: Nucleus, Organelles, and Organization of Genetic Material
1:45
Archaea vs. Bacteria: Cell Walls
2:20
Archaea vs. Bacteria: Number of Types of RNA Pol
2:29
Archaea vs. Bacteria: Membrane Lipids
2:53
Archaea vs. Bacteria: Introns
3:33
Bacteria: Pathogen
4:03
Bacteria: Decomposers and Fix Nitrogen
5:18
Bacteria: Aerobic, Anaerobic, Strict Anaerobes & Facultative Anaerobes
6:02
Phototrophs, Autotrophs, Heterotrophs and Chemotrophs
7:14
Phototrophs and Chemotrophs
7:50
Autotrophs and Heterotrophs
8:53
Photoautotrophs and Photoheterotrophs
10:15
Chemoautotroph and Chemoheterotrophs
11:07
Structure of Bacteria
12:21
Shapes: Cocci, Bacilli, Vibrio, and Spirochetes
12:26
Structures: Plasma Membrane and Cell Wall
14:23
Structures: Nucleoid Region, Plasmid, and Capsule Basal Apparatus, and Filament
15:30
Structures: Flagella, Basal Apparatus, Hook, and Filament
16:36
Structures: Pili, Fimbrae and Ribosome
18:00
Peptidoglycan: Gram + and Gram -
18:50
Bacterial Genomes and Reproduction
21:14
Bacterial Genomes
21:21
Reproduction of Bacteria
22:13
Transformation
23:26
Vector
24:34
Competent
25:15
Conjugation
25:53
Conjugation: F+ and R Plasmids
25:55
Example 1: Species
29:41
Example 2: Bacteria and Exchange of Genetic Material
32:31
Example 3: Ways in Which Bacteria are Beneficial to Other Organisms
33:48
Example 4: Domain Bacteria vs. Domain Archaea
34:53
Protists

1h 18m 48s

Intro
0:00
Classification of Protists
0:08
Classification of Protists
0:09
'Plant-like' Protists
2:06
'Animal-like' Protists
3:19
'Fungus-like' Protists
3:57
Serial Endosymbiosis Theory
5:15
Endosymbiosis Theory
5:33
Photosynthetic Protists
7:33
Life Cycles with a Diploid Adult
13:35
Life Cycles with a Diploid Adult
13:56
Life Cycles with a Haploid Adult
15:31
Life Cycles with a Haploid Adult
15:32
Alternation of Generations
17:22
Alternation of Generations: Multicellular Haploid & Diploid Phase
17:23
Plant-Like Protists
19:58
Euglenids
20:43
Dino Flagellates
22:57
Diatoms
26:07
Plant-Like Protists
28:44
Golden Algae
28:45
Brown Algeas
30:05
Plant-Like Protists
33:38
Red Algae
33:39
Green Algae
35:36
Green Algae: Chlamydomonus
37:44
Animal-Like Protists
40:04
Animal-Like Protists Overview
40:05
Sporozoans (Apicomplexans)
40:32
Alveolates
41:41
Sporozoans (Apicomplexans): Plasmodium & Malaria
42:59
Animal-Like Protists
48:44
Kinetoplastids
48:50
Example of Kinetoplastids: Trypanosomes & African Sleeping Sickness
49:30
Ciliate
50:42
Conjugation
53:16
Conjugation
53:26
Animal-Like Protists
57:08
Parabasilids
57:31
Diplomonads
59:06
Rhizopods
1:00:13
Forams
1:02:25
Radiolarians
1:03:28
Fungus-Like Protists
1:04:25
Fungus-Like Protists Overview
1:04:26
Slime Molds
1:05:15
Cellular Slime Molds: Feeding Stage
1:09:21
Oomycetes
1:11:15
Example 1: Alternation of Generations and Sexual Life Cycles
1:13:05
Example 2: Match Protists to Their Descriptions
1:14:12
Example 3: Three Structures that Protists Use for Motility
1:16:22
Example 4: Paramecium
1:17:04
Fungi

35m 24s

Intro
0:00
Introduction to Fungi
0:09
Introduction to Fungi
0:10
Mycologist
0:34
Examples of Fungi
0:45
Hyphae, Mycelia, Chitin, and Coencytic Fungi
2:26
Ancestral Protists
5:00
Role of Fungi in the Environment
5:35
Fungi as Decomposers
5:36
Mycorrrhiza
6:19
Lichen
8:52
Life Cycle of Fungi
11:32
Asexual Reproduction
11:33
Sexual Reproduction & Dikaryotic Cell
13:16
Chytridiomycota
18:12
Phylum Chytridiomycota
18:17
Zoospores
18:50
Zygomycota
19:07
Coenocytic & Zygomycota Life Cycle
19:08
Basidiomycota
24:27
Basidiomycota Overview
24:28
Basidiomycota Life Cycle
26:11
Ascomycota
28:00
Ascomycota Overview
28:01
Ascomycota Reproduction
28:50
Example 1: Fungi Fill in the Blank
31:02
Example 2: Name Two Roles Played by Fungi in the Environment
32:09
Example 3: Difference Between Diploid Cell and Dikaryon Cell
33:42
Example 4: Phylum of Fungi, Flagellated Spore, Coencytic
34:36
Invertebrates

1h 3m 3s

Intro
0:00
Porifera (Sponges)
0:33
Chordata
0:56
Porifera (Sponges): Sessile, Layers, Aceolomates, and Filter Feeders
1:24
Amoebocytes Cell
4:47
Choanocytes Cell
5:56
Sexual Reproduction
6:28
Cnidaria
8:05
Cnidaria Overview
8:06
Polyp & Medusa: Gastrovasular Cavity
8:29
Cnidocytes
9:42
Anthozoa
10:40
Cubozoa
11:23
Hydrozoa
11:53
Scyphoza
13:25
Platyhelminthes (Flatworms)
13:58
Flatworms: Tribloblastic, Bilateral Symmetry, and Cephalization
13:59
GI System
15:33
Excretory System
16:07
Nervous System
17:00
Turbellarians
17:36
Trematodes
18:42
Monageneans
21:32
Cestoda
21:55
Rotifera (Rotifers)
23:45
Rotifers: Digestive Tract, Pseudocoelem, and Stuctures
23:46
Reproduction: Parthenogenesis
25:33
Nematoda (Roundworms)
26:44
Nematoda (Roundworms)
26:45
Parasites: Pinworms & Hookworms
27:26
Annelida
28:36
Annelida Overview
28:37
Open Circulatory
29:21
Closed Circulatory
30:18
Nervous System
31:19
Excretory System
31:43
Oligochaete
32:07
Leeches
33:22
Polychaetes
34:42
Mollusca
35:26
Mollusca Features
35:27
Major Part 1: Visceral Mass
36:21
Major Part 2: Head-foot Region
36:49
Major Part 3: Mantle
37:13
Radula
37:49
Circulatory, Reproductive, Excretory, and Nervous System
38:14
Major Classes of Molluscs
39:12
Gastropoda
39:17
Polyplacophora
40:15
Bivales
40:41
Cephalopods
41:42
Arthropoda
43:35
Arthropoda Overview
43:36
Segmented Bodies
44:14
Exoskeleton
44:52
Jointed Appendages
45:28
Hemolyph, Excretory & Respiratory System
45:41
Myriapoda & Centipedes
47:15
Cheliceriforms
48:20
Crustcea
49:31
Herapoda
50:03
Echinodermata
52:59
Echinodermata
53:00
Watrer Vascular System
54:20
Selected Characteristics of Invertebrates
57:11
Selected Characteristics of Invertebrates
57:12
Example 1: Phylum Description
58:43
Example 2: Complex Animals
59:50
Example 3: Match Organisms to the Correct Phylum
1:01:03
Example 4: Phylum Arthropoda
1:02:01
Vertebrates

1h 7s

Intro
0:00
Phylum Chordata
0:06
Chordates Overview
0:07
Notochord and Dorsal Hollow Nerve Chord
1:24
Pharyngeal Clefts, Arches, and Post-anal Tail
3:41
Invertebrate Chordates
6:48
Lancelets
7:13
Tunicates
8:02
Hagfishes: Craniates
8:55
Vertebrate Chordates
10:41
Veterbrates Overview
10:42
Lampreys
11:00
Gnathostomes
12:20
Six Major Classes of Vertebrates
12:53
chondrichthyes
14:23
Chondrichthyes Overview
14:24
Ectothermic and Endothermic
14:42
Sharks: Lateral Line System, Neuromastsn, and Gills
15:27
Oviparous and Viviparous
17:23
Osteichthyes (Bony Fishes)
18:12
Osteichythes (Bony Fishes) Overview
18:13
Operculum
19:05
Swim Bladder
19:53
Ray-Finned Fishes
20:34
Lobe-Finned Fishes
20:58
Tetrapods
22:36
Tetrapods: Definition and Examples
22:37
Amphibians
23:53
Amphibians Overview
23:54
Order Urodela
25:51
Order Apoda
27:03
Order Anura
27:55
Reptiles
30:19
Reptiles Overview
30:20
Amniotes
30:37
Examples of Reptiles
32:46
Reptiles: Ectotherms, Gas Exchange, and Heart
33:40
Orders of Reptiles
34:17
Sphenodontia, Squamata, Testudines, and Crocodilia
34:21
Birds
36:09
Birds and Dinosaurs
36:18
Theropods
38:00
Birds: High Metabolism, Respiratory System, Lungs, and Heart
39:04
Birds: Endothermic, Bones, and Feathers
40:15
Mammals
42:33
Mammals Overview
42:35
Diaphragm and Heart
42:57
Diphydont
43:44
Synapsids
44:41
Monotremes
46:36
Monotremes
46:37
Marsupials
47:12
Marsupials: Definition and Examples
47:16
Convergent Evolution
48:09
Eutherians (Placental Mammals)
49:42
Placenta
49:43
Order Carnivora
50:48
Order Raodentia
51:00
Order Cetaceans
51:14
Primates
51:41
Primates Overview
51:42
Nails and Hands
51:58
Vision
52:51
Social Care for Young
53:28
Brain
53:43
Example 1: Distinguishing Characteristics of Chordates
54:33
Example 2: Match Description to Correct Term
55:56
Example 3: Bird's Anatomy
57:38
Example 4: Vertebrate Animal, Marine Environment, and Ectothermic
59:14
Section 9: Plants
Seedless Plants

34m 31s

Intro
0:00
Origin and Classification of Plants
0:06
Origin and Classification of Plants
0:07
Non-Vascular vs. Vascular Plants
1:29
Seedless Vascular & Seed Plants
2:28
Angiosperms & Gymnosperms
2:50
Alternation of Generations
3:54
Alternation of Generations
3:55
Bryophytes
7:58
Overview of Bryrophytes
7:59
Example: Moss Gametophyte
9:29
Example: Moss Sporophyte
9:50
Moss Life Cycle
10:12
Moss Life Cycle
10:13
Seedless Vascular Plants
13:23
Vascular Structures: Cell Walls, and Lignin
13:24
Homosporous
17:11
Heterosporous
17:48
Adaptations to Life on land
21:10
Adaptation 1: Cell Walls
21:38
Adaptation 2: Vascular Plants
21:59
Adaptation 3 : Xylem & Phloem
22:31
Adaptation 4: Seeds
23:07
Adaptation 5: Pollen
23:35
Adaptation 6: Stomata
24:45
Adaptation 7: Reduced Gametophyte Generation
25:32
Example 1: Bryophytes
26:39
Example 2: Sporangium, Lignin, Gametophyte, and Antheridium
28:34
Example 3: Adaptations to Life on Land
29:47
Example 4: Life Cycle of Plant
32:06
Plant Structure

1h 1m 21s

Intro
0:00
Plant Tissue
0:05
Dermal Tissue
0:15
Vascular Tissue
0:39
Ground Tissue
1:31
Cell Types in Plants
2:14
Parenchyma Cells
2:24
Collenchyma Cells
3:21
Sclerenchyma Cells
3:59
Xylem
5:04
Xylem: Tracheids and Vessel Elements
6:12
Gymnosperms vs. Angiosperms
7:53
Phloem
8:37
Phloem: Structures and Function
8:38
Sieve-Tube Elements
8:45
Companion Cells & Sieve Plates
9:11
Roots
10:08
Taproots & Fibrous
10:09
Aerial Roots & Prop Roots
11:41
Structures and Functions of Root: Dicot & Monocot
13:00
Pericyle
16:57
The Nitrogen Cylce
18:05
The Nitrogen Cycle
18:06
Mycorrhizae
24:20
Mycorrhizae
24:23
Ectomycorrhiza
26:03
Endomycorrhiza
26:25
Stems
26:53
Stems
26:54
Vascular Bundles of Monocots and Dicots
28:18
Leaves
29:48
Blade & Petiole
30:13
Upper Epidermis, Lower Epidermis & Cuticle
30:39
Ground Tissue, Palisade Mesophyll, Spongy Mesophyll
31:35
Stomata Pores
33:23
Guard Cells
34:15
Vascular Tissues: Vascular Bundles and Bundle Sheath
34:46
Stomata
36:12
Stomata & Gas Exchange
36:16
Guard Cells, Flaccid, and Turgid
36:43
Water Potential
38:03
Factors for Opening Stoma
40:35
Factors Causing Stoma to Close
42:44
Overview of Plant Growth
44:23
Overview of Plant Growth
44:24
Primary Plant Growth
46:19
Apical Meristems
46:25
Root Growth: Zone of Cell Division
46:44
Root Growth: Zone of Cell Elongation
47:35
Root Growth: Zone of Cell Differentiation
47:55
Stem Growth: Leaf Primodia
48:16
Secondary Plant Growth
48:48
Secondary Plant Growth Overview
48:59
Vascular Cambium: Secondary Xylem and Phloem
49:38
Cork Cambium: Periderm and Lenticels
51:10
Example 1: Leaf Structures
53:30
Example 2: List Three Types of Plant Tissue and their Major Functions
55:13
Example 3: What are Two Factors that Stimulate the Opening or Closing of Stomata?
56:58
Example 4: Plant Growth
59:18
Gymnosperms and Angiosperms

1h 1m 51s

Intro
0:00
Seed Plants
0:22
Sporopollenin
0:58
Heterosporous: Megasporangia
2:49
Heterosporous: Microsporangia
3:19
Gymnosperms
5:20
Gymnosperms
5:21
Gymnosperm Life Cycle
7:30
Gymnosperm Life Cycle
7:31
Flower Structure
15:15
Petal & Pollination
15:48
Sepal
16:52
Stamen: Anther, Filament
17:05
Pistill: Stigma, Style, Ovule, Ovary
17:55
Complete Flowers
20:14
Angiosperm Gametophyte Formation
20:47
Male Gametophyte: Microsporocytes, Microsporangia & Meiosis
20:57
Female Gametophyte: Megasporocytes & Meiosis
24:22
Double Fertilization
25:43
Double Fertilization: Pollen Tube and Endosperm
25:44
Angiosperm Life Cycle
29:43
Angiosperm Life Cycle
29:48
Seed Structure and Development
33:37
Seed Structure and Development
33:38
Pollen Dispersal
37:53
Abiotic
38:28
Biotic
39:30
Prevention of Self-Pollination
40:48
Mechanism 1
41:08
Mechanism 2: Dioecious
41:37
Mechanism 3
42:32
Self-Incompatibility
43:08
Gametophytic Self-Incompatibility
44:38
Sporophytic Self-Incompatibility
46:50
Asexual Reproduction
48:33
Asexual Reproduction & Vegetative Propagation
48:34
Graftiry
50:19
Monocots and Dicots
51:34
Monocots vs.Dicots
51:35
Example 1: Double Fertilization
54:43
Example 2: Mechanisms of Self-Fertilization
56:02
Example 3: Monocots vs. Dicots
58:11
Example 4: Flower Structures
1:00:11
Transport of Nutrients and Water in Plants

40m 30s

Intro
0:00
Review of Plant Cell Structure
0:14
Cell Wall, Plasma Membrane, Middle lamella, and Cytoplasm
0:15
Plasmodesmata, Chloroplasts, and Central Vacuole
3:24
Water Absorption by Plants
4:28
Root Hairs and Mycorrhizae
4:30
Osmosis and Water Potential
5:41
Apoplast and Symplast Pathways
10:01
Apoplast and Symplast Pathways
10:02
Xylem Structure
21:02
Tracheids and Vessel Elements
21:03
Bulk Flow
23:00
Transpiration
23:26
Cohesion
25:10
Adhesion
26:10
Phloem Structure
27:25
Pholem
27:26
Sieve-Tube Elements
27:48
Companion Cells
28:17
Translocation
28:42
Sugar Source and Sugar Sink Overview
28:43
Example of Sugar Sink
30:01
Example of Sugar Source
30:48
Example 1: Match the Following Terms to their Description
33:17
Example 2: Water Potential
34:58
Example 3: Bulk Flow
36:56
Example 4: Sugar Sink and Sugar Source
38:33
Plant Hormones and Tropisms

48m 10s

Intro
0:00
Plant Cell Signaling
0:17
Plant Cell Signaling Overview
0:18
Step 1: Reception
1:03
Step 2: Transduction
2:32
Step 3: Response
2:58
Second Messengers
3:52
Protein Kinases
4:42
Auxins
6:14
Auxins
6:18
Indoleacetic Acid (IAA)
7:23
Cytokinins and Gibberellins
11:10
Cytokinins: Apical Dominance & Delay of Aging
11:16
Gibberellins: 'Bolting'
13:51
Ethylene
15:33
Ethylene
15:34
Positive Feedback
15:46
Leaf Abscission
18:05
Mechanical Stress: Triple Response
19:36
Abscisic Acid
21:10
Abscisic Acid
21:15
Tropisms
23:11
Positive Tropism
23:50
Negative Tropism
24:07
Statoliths
26:21
Phytochromes and Photoperiodism
27:48
Phytochromes: PR and PFR
27:56
Circadian Rhythms
32:06
Photoperiod
33:13
Photoperiodism
33:38
Gerner & Allard
34:35
Short-Day Plant
35:22
Long-Day Plant
37:00
Example 1: Plant Hormones
41:28
Example 2: Cytokinins & Gibberellins
43:00
Example 3: Match the Following Terms to their Description
44:46
Example 4: Hormones & Cell Response
46:14
Section 10: Animal Structure and Physiology
The Respiratory System

48m 14s

Intro
0:00
Gas Exchange in Animals
0:17
Respiration
0:19
Ventilation
1:09
Characteristics of Respiratory Surfaces
1:53
Gas Exchange in Aquatic Animals
3:05
Simple Aquatic Animals
3:06
Gills & Gas Exchange in Complex Aquatic Animals
3:49
Countercurrent Exchange
6:12
Gas Exchange in Terrestrial Animals
13:46
Earthworms
14:07
Internal Respiratory
15:35
Insects
16:55
Circulatory Fluid
19:06
The Human Respiratory System
21:21
Nasal Cavity, Pharynx, Larynx, and Epiglottis
21:50
Bronchus, Bronchiole, Trachea, and Alveoli
23:38
Pulmonary Surfactants
28:05
Circulatory System: Hemoglobin
29:13
Ventilation
30:28
Inspiration/Expiration: Diaphragm, Thorax, and Abdomen
30:33
Breathing Control Center: Regulation of pH
34:34
Example 1: Tracheal System in Insects
39:08
Example 2: Countercurrent Exchange
42:09
Example 3: Respiratory System
44:10
Example 4: Diaphragm, Ventilation, pH, and Regulation of Breathing
45:31
The Circulatory System

1h 20m 21s

Intro
0:00
Types of Circulatory Systems
0:07
Circulatory System Overview
0:08
Open Circulatory System
3:19
Closed Circulatory System
5:58
Blood Vessels
7:51
Arteries
8:16
Veins
10:01
Capillaries
12:35
Vasoconstriction and Vasodilation
13:10
Vasoconstriction
13:11
Vasodilation
13:47
Thermoregulation
14:32
Blood
15:53
Plasma
15:54
Cellular Component: Red Blood Cells
17:41
Cellular Component: White Blood Cells
20:18
Platelets
21:14
Blood Types
21:35
Clotting
27:04
Blood, Fibrin, and Clotting
27:05
Hemophilia
30:26
The Heart
31:09
Structures and Functions of the Heart
31:19
Pulmonary and Systemic Circulation
40:20
Double Circuit: Pulmonary Circuit and Systemic Circuit
40:21
The Cardiac Cycle
42:35
The Cardiac Cycle
42:36
Autonomic Nervous System
50:00
Hemoglobin
51:25
Hemoglobin & Hemocyanin
51:26
Oxygen-Hemoglobin Dissociation Curve
55:30
Oxygen-Hemoglobin Dissociation Curve
55:44
Transport of Carbon Dioxide
1:06:31
Transport of Carbon Dioxide
1:06:37
Example 1: Pathway of Blood
1:12:48
Example 2: Oxygenated Blood, Pacemaker, and Clotting
1:15:24
Example 3: Vasodilation and Vasoconstriction
1:16:19
Example 4: Oxygen-Hemoglobin Dissociation Curve
1:18:13
The Digestive System

56m 11s

Intro
0:00
Introduction to Digestion
0:07
Digestive Process
0:08
Intracellular Digestion
0:45
Extracellular Digestion
1:44
Types of Digestive Tracts
2:08
Gastrovascular Cavity
2:09
Complete Gastrointestinal Tract (Alimentary Canal)
3:54
'Crop'
4:43
The Human Digestive System
5:41
Structures of the Human Digestive System
5:47
The Oral Cavity and Esophagus
7:47
Mechanical & Chemical Digestion
7:48
Salivary Glands
8:55
Pharynx and Epigloltis
9:43
Peristalsis
11:35
The Stomach
12:57
Lower Esophageal Sphincter
13:00
Gastric Gland, Parietal Cells, and Pepsin
14:32
Mucus Cell
15:48
Chyme & Pyloric Sphincter
17:32
The Pancreas
18:31
Endocrine and Exocrine
19:03
Amylase
20:05
Proteases
20:51
Lipases
22:20
The Liver
23:08
The Liver & Production of Bile
23:09
The Small Intestine
24:37
The Small Intestine
24:38
Duodenum
27:44
Intestinal Enzymes
28:41
Digestive Enzyme
33:30
Site of Production: Mouth
33:43
Site of Production: Stomach
34:03
Site of Production: Pancreas
34:16
Site of Production: Small Intestine
36:18
Absorption of Nutrients
37:51
Absorption of Nutrients: Jejunum and Ileum
37:52
The Large Intestine
44:52
The Large Intestine: Colon, Cecum, and Rectum
44:53
Regulation of Digestion by Hormones
46:55
Gastrin
47:21
Secretin
47:50
Cholecystokinin (CCK)
48:00
Example 1: Intestinal Cell, Bile, and Digestion of Fats
48:29
Example 2: Matching
51:06
Example 3: Digestion and Absorption of Starch
52:18
Example 4: Large Intestine and Gastric Fluids
54:52
The Excretory System

1h 12m 14s

Intro
0:00
Nitrogenous Wastes
0:08
Nitrogenous Wastes Overview
0:09
NH3
0:39
Urea
2:43
Uric Acid
3:31
Osmoregulation
4:56
Osmoregulation
5:05
Saltwater Fish vs. Freshwater Fish
8:58
Types of Excretory Systems
13:42
Protonephridia
13:50
Metanephridia
16:15
Malpighian Tubule
19:05
The Human Excretory System
20:45
Kidney, Ureter, bladder, Urethra, Medula, and Cortex
20:53
Filtration, Reabsorption and Secretion
22:53
Filtration
22:54
Reabsorption
24:16
Secretion
25:20
The Nephron
26:23
The Nephron
26:24
The Nephron, cont.
41:45
Descending Loop of Henle
41:46
Ascending Loop of Henle
45:45
Antidiuretic Hormone
54:30
Antidiuretic Hormone (ADH)
54:31
Aldosterone
58:58
Aldosterone
58:59
Example 1: Nephron of an Aquatic Mammal
1:04:21
Example 2: Uric Acid & Saltwater Fish
1:06:36
Example 3: Nephron
1:09:14
Example 4: Gastrointestinal Infection
1:10:41
The Endocrine System

51m 12s

Intro
0:00
The Endocrine System Overview
0:07
Thyroid
0:08
Exocrine
1:56
Pancreas
2:44
Paracrine Signaling
4:06
Pheromones
5:15
Mechanisms of Hormone Action
6:06
Reception, Transduction, and Response
7:06
Classes of Hormone
10:05
Negative Feedback: Testosterone Example
12:16
The Pancreas
15:11
The Pancreas & islets of Langerhan
15:12
Insulin
16:02
Glucagon
17:28
The Anterior Pituitary
19:25
Thyroid Stimulating Hormone
20:24
Adrenocorticotropic Hormone
21:16
Follide Stimulating Hormone
22:04
Luteinizing Hormone
22:45
Growth Hormone
23:45
Prolactin
24:24
Melanocyte Stimulating Hormone
24:55
The Hypothalamus and Posterior Pituitary
25:45
Hypothalamus, Oxytocin, Antidiuretic Hormone (ADH), and Posterior Pituitary
25:46
The Adrenal Glands
31:20
Adrenal Cortex
31:56
Adrenal Medulla
34:29
The Thyroid
35:54
Thyroxine
36:09
Calcitonin
40:27
The Parathyroids
41:44
Parathyroids Hormone (PTH)
41:45
The Ovaries and Testes
43:32
Estrogen, Progesterone, and Testosterone
43:33
Example 1: Match the Following Hormones with their Descriptions
45:38
Example 2: Pancreas, Endocrine Organ & Exocrine Organ
47:06
Example 3: Insulin and Glucagon
48:28
Example 4: Increased Level of Cortisol in Blood
50:25
The Nervous System

1h 10m 38s

Intro
0:00
Types of Nervous Systems
0:28
Nerve Net
0:37
Flatworm
1:07
Cephalization
1:52
Arthropods
2:44
Echinoderms
3:11
Nervous System Organization
3:40
Nervous System Organization Overview
3:41
Automatic Nervous System: Sympathetic & Parasympathetic
4:42
Neuron Structure
6:57
Cell Body & Dendrites
7:16
Axon & Axon Hillock
8:20
Synaptic Terminals, Mylenin, and Nodes of Ranvier
9:01
Pre-synaptic and Post-synaptic Cells
10:16
Pre-synaptic Cells
10:17
Post-synaptic Cells
11:05
Types of Neurons
11:50
Sensory Neurons
11:54
Motor Neurons
13:12
Interneurons
14:24
Resting Potential
15:14
Membrane Potential
15:25
Resting Potential: Chemical Gradient
16:06
Resting Potential: Electrical Gradient
19:18
Gated Ion Channels
24:40
Voltage-Gated & Ligand-Gated Ion Channels
24:48
Action Potential
30:09
Action Potential Overview
30:10
Step 1
32:07
Step 2
32:17
Step 3
33:12
Step 4
35:14
Step 5
36:39
Action Potential Transmission
39:04
Action Potential Transmission
39:05
Speed of Conduction
41:19
Saltatory Conduction
42:58
The Synapse
44:17
The Synapse: Presynaptic & Postsynaptic Cell
44:31
Examples of Neurotransmitters
50:05
Brain Structure
51:57
Meniges
52:19
Cerebrum
52:56
Corpus Callosum
53:13
Gray & White Matter
53:38
Cerebral Lobes
55:35
Cerebellum
56:00
Brainstem
56:30
Medulla
56:51
Pons
57:22
Midbrain
57:55
Thalamus
58:25
Hypothalamus
58:58
Ventricles
59:51
The Spinal Cord
1:00:29
Sensory Stimuli
1:00:30
Reflex Arc
1:01:41
Example 1: Automatic Nervous System
1:04:38
Example 2: Synaptic Terminal and the Release of Neurotransmitters
1:06:22
Example 3: Volted-Gated Ion Channels
1:08:00
Example 4: Neuron Structure
1:09:26
Musculoskeletal System

39m 29s

Intro
0:00
Skeletal System Types and Function
0:30
Skeletal System
0:31
Exoskeleton
1:34
Endoskeleton
2:32
Skeletal System Components
2:55
Bone
3:06
Cartilage
5:04
Tendons
6:18
Ligaments
6:34
Skeletal Muscle
6:52
Skeletal Muscle
7:24
Sarcomere
9:50
The Sliding Filament Theory
13:12
The Sliding Filament Theory: Muscle Contraction
13:13
The Neuromuscular Junction
17:24
The Neuromuscular Junction: Motor Neuron & Muscle Fiber
17:26
Sarcolemma, Sarcoplasmic
21:54
Tropomyosin & Troponin
23:35
Summation and Tetanus
25:26
Single Twitch, Summation of Two Twitches, and Tetanus
25:27
Smooth Muscle
28:50
Smooth Muscle
28:58
Cardiac Muscle
30:40
Cardiac Muscle
30:42
Summary of Muscle Types
32:07
Summary of Muscle Types
32:08
Example 1: Contraction and Skeletal Muscle
33:15
Example 2: Skeletal Muscle and Smooth Muscle
36:23
Example 3: Muscle Contraction, Bone, and Nonvascularized Connective Tissue
37:31
Example 4: Sarcomere
38:17
The Immune System

1h 24m 28s

Intro
0:00
The Lymphatic System
0:16
The Lymphatic System Overview
0:17
Function 1
1:23
Function 2
2:27
Barrier Defenses
3:41
Nonspecific vs. Specific Immune Defenses
3:42
Barrier Defenses
5:12
Nonspecific Cellular Defenses
7:50
Nonspecific Cellular Defenses Overview
7:53
Phagocytes
9:29
Neutrophils
11:43
Macrophages
12:15
Natural Killer Cells
12:55
Inflammatory Response
14:19
Complement
18:16
Interferons
18:40
Specific Defenses - Acquired Immunity
20:12
T lymphocytes and B lymphocytes
20:13
B Cells
23:35
B Cells & Humoral Immunity
23:41
Clonal Selection
29:50
Clonal Selection
29:51
Primary Immune Response
34:28
Secondary Immune Response
35:31
Cytotoxic T Cells
38:41
Helper T Cells
39:20
Major Histocompatibility Complex Molecules
40:44
Major Histocompatibility Complex Molecules
40:55
Helper T Cells
52:36
Helper T Cells
52:37
Mechanisms of Antibody Action
59:00
Mechanisms of Antibody Action
59:01
Opsonization
1:00:01
Complement System
1:01:57
Classes of Antibodies
1:02:45
IgM
1:03:01
IgA
1:03:17
IgG
1:03:53
IgE
1:04:10
Passive and Active Immunity
1:05:00
Passive Immunity
1:05:01
Active Immunity
1:07:49
Recognition of Self and Non-Self
1:09:32
Recognition of Self and Non-Self
1:09:33
Self-Tolerance & Autoimmune Diseases
1:10:50
Immunodeficiency
1:13:27
Immunodeficiency
1:13:28
Chemotherapy
1:13:56
AID
1:14:27
Example 1: Match the Following Terms with their Descriptions
1:15:26
Example 2: Three Components of Non-specific Immunity
1:17:59
Example 3: Immunodeficient
1:21:19
Example 4: Self-tolerance and Autoimmune Diseases
1:23:07
Section 11: Animal Reproduction and Development
Reproduction

1h 1m 41s

Intro
0:00
Asexual Reproduction
0:17
Fragmentation
0:53
Fission
1:54
Parthenogenesis
2:38
Sexual Reproduction
4:00
Sexual Reproduction
4:01
Hermaphrodite
8:08
The Male Reproduction System
8:54
Seminiferous Tubules & Leydig Cells
8:55
Epididymis
9:48
Seminal Vesicle
11:19
Bulbourethral
12:37
The Female Reproductive System
13:25
Ovaries
13:28
Fallopian
14:50
Endometrium, Uterus, Cilia, and Cervix
15:03
Mammary Glands
16:44
Spermatogenesis
17:08
Spermatogenesis
17:09
Oogenesis
21:01
Oogenesis
21:02
The Menstrual Cycle
27:56
The Menstrual Cycle: Ovarian and Uterine Cycle
27:57
Summary of the Ovarian and Uterine Cycles
42:54
Ovarian
42:55
Uterine
44:51
Oxytocin and Prolactin
46:33
Oxytocin
46:34
Prolactin
47:00
Regulation of the Male Reproductive System
47:28
Hormones: GnRH, LH, FSH, and Testosterone
47:29
Fertilization
50:11
Fertilization
50:12
Structures of Egg
50:28
Acrosomal Reaction
51:36
Cortical Reaction
53:09
Example 1: List Three Differences between Spermatogenesis and oogenesis
55:36
Example 2: Match the Following Terms to their Descriptions
57:34
Example 3: Pregnancy and the Ovarian Cycle
58:44
Example 4: Hormone
1:00:43
Development

50m 5s

Intro
0:00
Cleavage
0:31
Cleavage
0:32
Meroblastic
2:06
Holoblastic Cleavage
3:23
Protostomes
4:34
Deuterostomes
5:13
Totipotent
5:52
Blastula Formation
6:42
Blastula
6:46
Gastrula Formation
8:12
Deuterostomes
11:02
Protostome
11:44
Ectoderm
12:17
Mesoderm
12:55
Endoderm
13:40
Cytoplasmic Determinants
15:19
Cytoplasmic Determinants
15:23
The Bird Embryo
22:52
Cleavage
23:35
Blastoderm
23:55
Primitive Streak
25:38
Migration and Differentiation
27:09
Extraembryonic Membranes
28:33
Extraembryonic Membranes
28:34
Chorion
30:02
Yolk Sac
30:36
Allantois
31:04
The Mammalian Embryo
32:18
Cleavage
32:28
Blastocyst
32:44
Trophoblast
34:37
Following Implantation
35:48
Organogenesis
37:04
Organogenesis, Notochord and Neural Tube
37:05
Induction
40:15
Induction
40:39
Fate Mapping
41:40
Example 1: Processes and Stages of Embryological Development
42:49
Example 2: Transplanted Cells
44:33
Example 3: Germ Layer
46:41
Example 4: Extraembryonic Membranes
47:28
Section 12: Animal Behavior
Animal Behavior

47m 48s

Intro
0:00
Introduction to Animal Behavior
0:05
Introduction to Animal Behavior
0:06
Ethology
1:04
Proximate Cause & Ultimate Cause
1:46
Fixed Action Pattern
3:07
Sign Stimulus
3:40
Releases and Example
3:55
Exploitation and Example
7:23
Learning
8:56
Habituation, Associative Learning, and Imprinting
8:57
Habituation
10:03
Habituation: Definition and Example
10:04
Associative Learning
11:47
Classical
12:19
Operant Conditioning
13:40
Positive & Negative Reinforcement
14:59
Positive & Negative Punishment
16:13
Extinction
17:28
Imprinting
17:47
Imprinting: Definition and Example
17:48
Social Behavior
20:12
Cooperation
20:38
Agonistic
21:37
Dorminance Heirarchies
23:23
Territoriality
24:08
Altruism
24:55
Communication
26:56
Communication
26:57
Mating
32:38
Mating Overview
32:40
Promiscuous
33:13
Monogamous
33:32
Polygamous
33:48
Intrasexual
34:22
Intersexual Selection
35:08
Foraging
36:08
Optimal Foraging Model
36:39
Foraging
37:47
Movement
39:12
Kinesis
39:20
Taxis
40:17
Migration
40:54
Lunar Cycles
42:02
Lunar Cycles
42:08
Example 1: Types of Conditioning
43:19
Example 2: Match the Following Terms to their Descriptions
44:12
Example 3: How is the Optimal Foraging Model Used to Explain Foraging Behavior
45:47
Example 4: Learning
46:54
Section 13: Ecology
Biomes

58m 49s

Intro
0:00
Ecology
0:08
Ecology
0:14
Environment
0:22
Integrates
1:41
Environment Impacts
2:20
Population and Distribution
3:20
Population
3:21
Range
4:50
Potential Range
5:10
Abiotic
5:46
Biotic
6:22
Climate
7:55
Temperature
8:40
Precipitation
10:00
Wind
10:37
Sunlight
10:54
Macroclimates & Microclimates
11:31
Other Abiotic Factors
12:20
Geography
12:28
Water
13:17
Soil and Rocks
13:48
Sunlight
14:42
Sunlight
14:43
Seasons
15:43
June Solstice, December Solstice, March Equinox, and September Equinox
15:44
Tropics
19:00
Seasonability
19:39
Wind and Weather Patterns
20:44
Vertical Circulation
20:51
Surface Wind Patterns
25:18
Local Climate Effects
26:51
Local Climate Effects
26:52
Terrestrial Biomes
30:04
Biome
30:05
Forest
31:02
Tropical Forest
32:00
Tropical Forest
32:01
Temperate Broadleaf Forest
32:55
Temperate Broadleaf Forest
32:56
Coniferous/Taiga Forest
34:10
Coniferous/Taiga Forest
34:11
Desert
36:05
Desert
36:06
Grassland
37:45
Grassland
37:46
Tundra
40:09
Tundra
40:10
Freshwater Biomes
42:25
Freshwater Biomes: Zones
42:27
Eutrophic Lakes
44:24
Oligotrophic Lakes
45:01
Lakes Turnover
46:03
Rivers
46:51
Wetlands
47:40
Estuary
48:11
Marine Biomes
48:45
Marine Biomes: Zones
48:46
Example 1: Diversity of Life
52:18
Example 2: Marine Biome
53:08
Example 3: Season
54:20
Example 4: Biotic vs. Abiotic
55:54
Population

41m 16s

Intro
0:00
Population
0:07
Size 'N'
0:16
Density
0:41
Dispersion
1:01
Measure Population: Count Individuals, Sampling, and Proxymeasure
2:26
Mortality
7:29
Mortality and Survivorship
7:30
Age Structure Diagrams
11:52
Expanding with Rapid Growth, Expanding, and Stable
11:58
Population Growth
15:39
Biotic Potential & Exponential Growth
15:43
Logistic Population Growth
19:07
Carrying Capacity (K)
19:18
Limiting Factors
20:55
Logistic Model and Oscillation
22:55
Logistic Model and Oscillation
22:56
Changes to the Carrying Capacity
24:36
Changes to the Carrying Capacity
24:37
Growth Strategies
26:07
'r-selected' or 'r-strategist'
26:23
'K-selected' or 'K-strategist'
27:47
Human Population
30:15
Human Population and Exponential Growth
30:21
Case Study - Lynx and Hare
31:54
Case Study - Lynx and Hare
31:55
Example 1: Estimating Population Size
34:35
Example 2: Population Growth
36:45
Example 3: Carrying Capacity
38:17
Example 4: Types of Dispersion
40:15
Communities

1h 6m 26s

Intro
0:00
Community
0:07
Ecosystem
0:40
Interspecific Interactions
1:14
Competition
2:45
Competition Overview
2:46
Competitive Exclusion
3:57
Resource Partitioning
4:45
Character Displacement
6:22
Predation
7:46
Predation
7:47
True Predation
8:05
Grazing/ Herbivory
8:39
Predator Adaptation
10:13
Predator Strategies
10:22
Physical Features
11:02
Prey Adaptation
12:14
Prey Adaptation
12:23
Aposematic Coloration
13:35
Batesian Mimicry
14:32
Size
15:42
Parasitism
16:48
Symbiotic Relationship
16:54
Ectoparasites
18:31
Endoparasites
18:53
Hyperparisitism
19:21
Vector
20:08
Parasitoids
20:54
Mutualism
21:23
Resource - Resource mutualism
21:34
Service - Resource Mutualism
23:31
Service - Service Mutualism: Obligate & Facultative
24:23
Commensalism
26:01
Commensalism
26:03
Symbiosis
27:31
Trophic Structure
28:35
Producers & Consumers: Autotrophs & Heterotrophs
28:36
Food Chain
33:26
Producer & Consumers
33:38
Food Web
39:01
Food Web
39:06
Significant Species within Communities
41:42
Dominant Species
41:50
Keystone Species
42:44
Foundation Species
43:41
Community Dynamics and Disturbances
44:31
Disturbances
44:33
Duration
47:01
Areal Coverage
47:22
Frequency
47:48
Intensity
48:04
Intermediate Level of Disturbance
48:20
Ecological Succession
50:29
Primary and Secondary Ecological Succession
50:30
Example 1: Competition Situation & Outcome
57:18
Example 2: Food Chains
1:00:08
Example 3: Ecological Units
1:02:44
Example 4: Disturbances & Returning to the Original Climax Community
1:04:30
Energy and Ecosystems

57m 42s

Intro
0:00
Ecosystem: Biotic & Abiotic Components
0:15
First Law of Thermodynamics & Energy Flow
0:40
Gross Primary Productivity (GPP)
3:52
Net Primary Productivity (NPP)
4:50
Biogeochemical Cycles
7:16
Law of Conservation of Mass & Biogeochemical Cycles
7:17
Water Cycle
10:55
Water Cycle
10:57
Carbon Cycle
17:52
Carbon Cycle
17:53
Nitrogen Cycle
22:40
Nitrogen Cycle
22:41
Phosphorous Cycle
29:34
Phosphorous Cycle
29:35
Climate Change
33:20
Climate Change
33:21
Eutrophication
39:38
Nitrogen
40:34
Phosphorous
41:29
Eutrophication
42:55
Example 1: Energy and Ecosystems
45:28
Example 2: Atmospheric CO2
48:44
Example 3: Nitrogen Cycle
51:22
Example 4: Conversion of a Forest near a Lake to Farmland
53:20
Section 14: Laboratory Review
Laboratory Review

2h 4m 30s

Intro
0:00
Lab 1: Diffusion and Osmosis
0:09
Lab 1: Diffusion and Osmosis
0:10
Lab 1: Water Potential
11:55
Lab 1: Water Potential
11:56
Lab 2: Enzyme Catalysis
18:30
Lab 2: Enzyme Catalysis
18:31
Lab 3: Mitosis and Meiosis
27:40
Lab 3: Mitosis and Meiosis
27:41
Lab 3: Mitosis and Meiosis
31:50
Ascomycota Life Cycle
31:51
Lab 4: Plant Pigments and Photosynthesis
40:36
Lab 4: Plant Pigments and Photosynthesis
40:37
Lab 5: Cell Respiration
49:56
Lab 5: Cell Respiration
49:57
Lab 6: Molecular Biology
55:06
Lab 6: Molecular Biology & Transformation 1st Part
55:07
Lab 6: Molecular Biology
1:01:16
Lab 6: Molecular Biology 2nd Part
1:01:17
Lab 7: Genetics of Organisms
1:07:32
Lab 7: Genetics of Organisms
1:07:33
Lab 7: Chi-square Analysis
1:13:00
Lab 7: Chi-square Analysis
1:13:03
Lab 8: Population Genetics and Evolution
1:20:41
Lab 8: Population Genetics and Evolution
1:20:42
Lab 9: Transpiration
1:24:02
Lab 9: Transpiration
1:24:03
Lab 10: Physiology of the Circulatory System
1:31:05
Lab 10: Physiology of the Circulatory System
1:31:06
Lab 10: Temperature and Metabolism in Ectotherms
1:38:25
Lab 10: Temperature and Metabolism in Ectotherms
1:38:30
Lab 11: Animal Behavior
1:40:52
Lab 11: Animal Behavior
1:40:53
Lab 12: Dissolved Oxygen & Aquatic Primary Productivity
1:45:36
Lab 12: Dissolved Oxygen & Aquatic Primary Productivity
1:45:37
Lab 12: Primary Productivity
1:49:06
Lab 12: Primary Productivity
1:49:07
Example 1: Chi-square Analysis
1:56:31
Example 2: Mitosis
1:59:28
Example 3: Transpiration of Plants
2:00:27
Example 4: Population Genetic
2:01:16
Section 15: The AP Biology Test
Understanding the Basics

13m 2s

Intro
0:00
AP Biology Structure
0:18
Section I
0:31
Section II
1:16
Scoring
2:04
The Four 'Big Ideas'
3:51
Process of Evolution
4:37
Biological Systems Utilize
4:44
Living Systems
4:55
Biological Systems Interact
5:03
Items to Bring to the Test
7:56
Test Taking Tips
9:53
Section 16: Practice Test (Barron's 4th Edition)
AP Biology Practice Exam: Section I, Part A, Multiple Choice Questions 1-31

1h 4m 29s

Intro
0:00
AP Biology Practice Exam
0:14
Multiple Choice 1
0:40
Multiple Choice 2
2:27
Multiple Choice 3
4:30
Multiple Choice 4
6:43
Multiple Choice 5
9:27
Multiple Choice 6
11:32
Multiple Choice 7
12:54
Multiple Choice 8
14:42
Multiple Choice 9
17:06
Multiple Choice 10
18:42
Multiple Choice 11
20:49
Multiple Choice 12
23:23
Multiple Choice 13
26:20
Multiple Choice 14
27:52
Multiple Choice 15
28:44
Multiple Choice 16
33:07
Multiple Choice 17
35:31
Multiple Choice 18
39:43
Multiple Choice 19
40:37
Multiple Choice 20
42:47
Multiple Choice 21
45:58
Multiple Choice 22
49:49
Multiple Choice 23
53:44
Multiple Choice 24
55:12
Multiple Choice 25
55:59
Multiple Choice 26
56:50
Multiple Choice 27
58:08
Multiple Choice 28
59:54
Multiple Choice 29
1:01:36
Multiple Choice 30
1:02:31
Multiple Choice 31
1:03:50
AP Biology Practice Exam: Section I, Part A, Multiple Choice Questions 32-63

50m 44s

Intro
0:00
AP Biology Practice Exam
0:14
Multiple Choice 32
0:27
Multiple Choice 33
4:14
Multiple Choice 34
5:12
Multiple Choice 35
6:51
Multiple Choice 36
10:46
Multiple Choice 37
11:27
Multiple Choice 38
12:17
Multiple Choice 39
13:49
Multiple Choice 40
17:02
Multiple Choice 41
18:27
Multiple Choice 42
19:35
Multiple Choice 43
21:10
Multiple Choice 44
23:35
Multiple Choice 45
25:00
Multiple Choice 46
26:20
Multiple Choice 47
28:40
Multiple Choice 48
30:14
Multiple Choice 49
31:24
Multiple Choice 50
32:45
Multiple Choice 51
33:41
Multiple Choice 52
34:40
Multiple Choice 53
36:12
Multiple Choice 54
38:06
Multiple Choice 55
38:37
Multiple Choice 56
40:00
Multiple Choice 57
41:18
Multiple Choice 58
43:12
Multiple Choice 59
44:25
Multiple Choice 60
45:02
Multiple Choice 61
46:10
Multiple Choice 62
47:54
Multiple Choice 63
49:01
AP Biology Practice Exam: Section I, Part B, Grid In

21m 52s

Intro
0:00
AP Biology Practice Exam
0:17
Grid In Question 1
0:29
Grid In Question 2
3:49
Grid In Question 3
11:04
Grid In Question 4
13:18
Grid In Question 5
17:01
Grid In Question 6
19:30
AP Biology Practice Exam: Section II, Long Free Response Questions

31m 22s

Intro
0:00
AP Biology Practice Exam
0:18
Free Response 1
0:29
Free Response 2
20:47
AP Biology Practice Exam: Section II, Short Free Response Questions

24m 41s

Intro
0:00
AP Biology Practice Exam
0:15
Free Response 3
0:26
Free Response 4
5:21
Free Response 5
8:25
Free Response 6
11:38
Free Response 7
14:48
Free Response 8
22:14
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Lecture Comments (12)

0 answers

Post by Shikha Bansal on April 22, 2016

HI Dr.Carleen,

I love how detailed your videos are. I'm not taking ap bio yet, but I plan to next year. However, I was wondering if there are any practice sources to help me remember what i learn. Do you know any good resources to practice or review ap biology? Thanks!

1 answer

Last reply by: Dr Carleen Eaton
Wed Jan 8, 2014 7:12 PM

Post by Brian Kelley on November 22, 2013

Hey Dr. Eaton,

Great lecture. I just wanted to make a correction you may have not noticed. While discussing the heart at around 38:40, you said the "carotid" arteries feed the heart muscle oxygen. I believe you meant to say the "coronary" arteries are responsible for this.

1 answer

Last reply by: Dr Carleen Eaton
Tue Aug 27, 2013 2:01 PM

Post by Ziheng Wang on August 22, 2013

If vasoconstriction happens, wouldn't the blood pressure rise and increase blood flow despite the reduction in diameter?

0 answers

Post by Dr Carleen Eaton on May 22, 2013

Hi Muna - Thanks for pointing that out. I meant to say that capillaries are only a single cell thick. The part I wrote/said about cell walls was a mistake!

1 answer

Last reply by: Dr Carleen Eaton
Wed May 22, 2013 8:48 PM

Post by Muna Lakhani on May 22, 2013

On 12:55, you say that capillaries have a cell wall. I thought the animal cells had no cell wall, only plasma membrane. Can you clarify?

1 answer

Last reply by: Dr Carleen Eaton
Mon Mar 25, 2013 12:31 PM

Post by Seyeon Kim on March 25, 2013

Hello Dr. Carleen,

Would O+ also be an universal donator, since in the lecture O-is only mentioned?

1 answer

Last reply by: Dr Carleen Eaton
Fri Jan 25, 2013 2:31 PM

Post by Tejinder kaur on January 18, 2013

Hi Dr. Carleen,

Have you thought about teaching Microbiology or Molecular Biochemistry. You are such a great professor. I would love learn these subjects from you.

The Circulatory System

  • Arteries have thick walls and carry blood away from the heart. Veins carry blood towards the heart, have thinner walls and have valves to prevent backflow.
  • Capillaries are small vessels with very thin walls across which nutrients, hormones, gases and waste products can diffuse.
  • Blood contains fluid called plasma, as well as red blood cells and white blood cells. Red blood cells (erythrocytes) contain hemoglobin and transport oxygen. White blood cells (leukocytes) function in immunity. Platelets are cell fragments that play a role in clotting.
  • Red blood cells contain hemoglobin, a four subunit protein that binds cooperatively to oxygen.
  • The mammalian heart has four chambers. The right atrium and ventricle pump blood through the pulmonary circuit and the left atrium and ventricle pump blood through the systemic circuit.
  • The sinoatrial node (SA) node is the pacemaker for the heart.
  • Deoxygenated blood leaves organs and returns to the heart via the superior vena cava and the inferior vena cava. Blood drains into the right atrium and then enters the right the right ventricle. Blood is pumped through the pulmonary arteries into the lungs and the newly oxygenated blood returns to the heart via the pulmonary veins, draining into the left atrium and then the left ventricle. The left ventricle pumps blood through the aorta to tissues and organs.

The Circulatory System

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Types of Circulatory Systems 0:07
    • Circulatory System Overview
    • Open Circulatory System
    • Closed Circulatory System
  • Blood Vessels 7:51
    • Arteries
    • Veins
    • Capillaries
  • Vasoconstriction and Vasodilation 13:10
    • Vasoconstriction
    • Vasodilation
    • Thermoregulation
  • Blood 15:53
    • Plasma
    • Cellular Component: Red Blood Cells
    • Cellular Component: White Blood Cells
    • Platelets
    • Blood Types
  • Clotting 27:04
    • Blood, Fibrin, and Clotting
    • Hemophilia
  • The Heart 31:09
    • Structures and Functions of the Heart
  • Pulmonary and Systemic Circulation 40:20
    • Double Circuit: Pulmonary Circuit and Systemic Circuit
  • The Cardiac Cycle 42:35
    • The Cardiac Cycle
    • Autonomic Nervous System
  • Hemoglobin 51:25
    • Hemoglobin & Hemocyanin
  • Oxygen-Hemoglobin Dissociation Curve 55:30
    • Oxygen-Hemoglobin Dissociation Curve
  • Transport of Carbon Dioxide 1:06:31
    • Transport of Carbon Dioxide
  • Example 1: Pathway of Blood 1:12:48
  • Example 2: Oxygenated Blood, Pacemaker, and Clotting 1:15:24
  • Example 3: Vasodilation and Vasoconstriction 1:16:19
  • Example 4: Oxygen-Hemoglobin Dissociation Curve 1:18:13

Transcription: The Circulatory System

Welcome to Educator.com.0001

We will be continuing our discussion of animal physiology with the circulatory system.0002

The purpose of the circulatory system is to deliver oxygen, hormones and nutrients to the cells of the body0010

and to remove wastes including CO2 as well as other waste products from metabolic processes.0017

In simple animals such as sponges and jellies, all the cells are in contact with the external environment,0024

which means that a circulatory system is not necessary.0031

These cells can pick up nutrients and oxygen directly from the water, and these components can enter the cells via diffusion.0035

And then, waste products can exit into the water the same way.0045

Animals such as sponges and jellies have bodies that are only a couple of cell layers thick, so they are in contact with the water on the outside.0050

And then, on the inside of the body, you may recall, they have a gastrovascular cavity.0059

As the name suggests, it combines both vascular system functions and GI tract functions and allows that inner layer of cells to be in contact with the water.0068

So, there is no heart, vessels, no circulatory fluid, no blood.0079

A similar idea occurs in flatworms. Flatworms, due to their very flat body structure, also have cells that are entirely in contact with the environment.0085

So, their bodies are in very close contact with the environment, and by diffusion, oxygen can enter.0097

However, most animals are larger and more complex than these, and they cannot exchange gas and nutrients directly with the environment0105

for every single cell in the body, because most of their cells are not even in direct contact with the environment.0114

In the section of respiration, we talked about gas exchange and the idea that specialized respiratory systems include structures like lungs and gills,0122

which provide a means of gas exchange.0132

However, the oxygen needs to be delivered to all the cells of the body, and some of these cells are distant from where gas exchange is taking place.0135

Gas exchange takes place in the alveolus of the lung. However, the alveolus is nowhere near your leg.0144

So, somehow, that oxygen needs to get to the leg or the arm or the brain throughout all the cells of the body.0153

Diffusion is one way that gases can move, but this would be far too slow.0160

Waiting for oxygen to diffuse down to your leg or brain would be so slow that the muscle or the brain cell would die waiting.0165

So, diffusion is much too slow. In order to bring large amounts of oxygen and nutrients to the cells quickly, the circulatory system evolved.0173

I have been focusing on oxygen, but recall that nutrients that are obtained by digestion in the GI system also need to be delivered to distant cells.0184

So, animals also require a circulatory system to carry out that function, and there are two general types of circulatory systems: open and closed.0194

Here is shown an insect as an example of an organism that has an open circulatory system.0206

And an open circulatory system means that the blood at one point leaves the vessels.0213

It does not mean that there are not any vessels. There often are some vessels, but the fluid is not contained within the vessels the entire time.0219

Here, this represents a pump, so a simple heart, and the pump, the heart, will move the circulatory fluid through vessels like an aorta.0229

From there, the circulatory vessels will branch out, and then, the fluid will be dumped out, released out, into cavities called sinuses.0246

So, these sinuses surround organs, so there will be an organ in here.0258

The respiratory, or excuse me, the circulatory fluid enters that cavity, and it bathes the organs and cells in this fluid.0264

Therefore, the organ can pick up nutrients and other substances from the fluid, and it can let waste products release them out into the fluid.0273

The fluid is, then, picked back up and returned to the heart.0287

In an open circulatory system, the fluid is called hemolymph. It is not blood, and hemolymph differs from blood in some fundamental ways.0292

In organisms with a closed - so, this is an open circulatory system - circulatory system, there are two types of fluid:0303

one in the vessels and one that bathes tissues and organs called interstitial fluid.0312

Here, there is only one type of fluid. They are one and the same.0318

It is called hemolymph.0321

The other thing is that frequently, hemolymph is not the means of delivering oxygen and picking up carbon dioxide.0322

Recall from the respiratory system, animals like insects have a tracheal system that they use to deliver oxygen directly to the cells of the body.0329

They do not take in the gas, give it to the circulatory fluid and have the circulatory fluid deliver the gas.0340

Usually, hemolymph is responsible for delivering nutrients and other substances, but it is often not the means of oxygen delivery or CO2 transport.0348

This second type of system is the closed circulatory system, and here is an example of...here is an earthworm and annelid,0360

and that it will have a closed circulatory system, so most invertebrates have an open circulatory system.0371

There are exceptions such as annelids. Another exception is cephalopods have a closed circulatory system like squids and octopuses.0382

So, most invertebrates have an open system. There are some that have a closed system, and all vertebrates have a closed circulatory system.0398

In a closed circulatory system, blood remains within vessels the entire time.0409

The blood stays within the vessel. Here is the heart, blood vessel, artery, carrying blood away from the heart.0417

And these vessels, they branch out into capillaries, and oxygen and nutrients can diffuse across the walls of the capillary.0427

But, the blood does not leave the vessel. It stays in the vessel, and then, it is returned to the heart.0437

Therefore, in a closed circulatory system, the fluid within the vessels is the blood, and then, there is second type of fluid called interstitial fluid.0444

That is fluid that surrounds tissues in organs.0456

We are going to talk in depth now about mammalian circulation, again, with a focus on the human circulatory system.0463

I am going to start out talking about the different components of a circulatory system.0472

And the major components are vessels, some type of circulatory fluid - hemolymph in the open system, blood in the closed system - and a pump- the heart.0477

Starting out with blood vessels, there are three types of blood vessels that you need to know, and these are arteries, veins and capillaries.0493

Starting out with arteries, arteries pump blood or move blood away from the heart.0504

So, blood is pumped by the heart through the arteries, so they carry blood away from the heart, and they have thick muscular walls.0515

There are smooth muscles in the walls, and the walls are thick- thick-walled.0529

The blood within the arteries is under pressure. It is being pumped by the heart, so it is under a significant amount of pressure.0537

What happens is as the blood is pumped by the heart, it is under pressure when the heart contracts.0545

However, when the ventricles relax, the pressure decreases, but the thick walls of the artery prevent the pressure from the circulatory0553

system from dropping too low because once the pressure is decreased as the heart relaxes, the walls of the artery will spring back.0563

So, they are being pushed by the pressure that the blood is under, and then, they spring back.0573

And that recoil maintains the pressure within the arterial system.0579

Arteries branch into arterials and then, finally, capillaries.0585

The second type of vessel is the veins. Veins are carry blood towards the heart, so blood returning either from body tissues or from the lungs.0596

Most veins, therefore, carry deoxygenated blood. There is an exception, though.0623

By that same measure, most arteries carry oxygenated blood.0637

And I say most because there is an exception that we are going to talk about when we talk about the heart.0646

But, when you say "define an artery", it is part of the definition that it is carrying blood away from the heart.0652

Usually, it is oxygenated but not always because the blood carried by the pulmonary artery is going away from the heart.0659

It is going towards the lungs. Yet, it is deoxygenated.0670

That is why it is going to the lungs.0672

So, anyways, veins carry blood towards the heart, and it is usually, but not always, deoxygenated blood.0674

The walls of the veins are much thinner, relatively thin, compared to the arteries, and the blood in the veins is under a lower pressure than in the arteries.0681

Now, blood is returned to the heart in part by muscle contraction.0695

So, for example, the veins in your legs, when you walk or when you run, you move around.0700

The contraction of your leg muscles pushes your venous blood back up towards the heart.0704

And that is why if someone wants to improve their circulation, they need to walk around or why if somebody is bedridden,0711

they are immobile, they are at a higher risk for blood clots because the blood pools, which makes it tend to coagulate and cause a clot.0719

So, anyways, movement is important for circulation.0726

Because the venous blood is not under a lot pressure, veins contain valves.0730

And what the valves do is they prevent backflow, so it prevents the blood from draining back into your feet towards the0736

dependent lower parts of your body and helps keep blood flowing upward or towards the heart, flowing in the right direction.0745

It prevents backflow.0754

Finally, capillaries: capillaries are very small vessels, so they are very small.0757

And they have cell walls that are only a single cell thick, which allows for diffusion of nutrients and gases across the cell wall.0764

The diameter of capillaries is so small that red blood cells actually have to go through single file, so these are extremely vessels.0777

Some terms that you should understand relating to blood vessels are vasoconstriction and vasodilation.0793

Vasoconstriction refers to the constriction or narrowing of the blood vessels.0800

And this is the result of the contraction of the muscles in the walls of the artery.0813

This will result in an increase in blood pressure, so vasoconstriction increases blood pressure. The opposite is vasodilation.0819

In vasodilation, blood vessels open up. They become wider, so instead of constricting, they dilate, so dilation of vessels.0836

And this is going to decrease blood pressure.0853

For example, if somebody is bleeding, they lose a lot of their blood, their blood pressure will drop.0860

And one way to compensate for that is for the vessels to constrict, so vasoconstriction can maintain the blood pressure.0866

Vasoconstriction and vasodilation also play a role in thermoregulation.0873

Thermoregulation is the maintenance of a constant internal temperature.0879

Cold triggers vasoconstriction, so if the blood vessels constrict, their diameter becomes smaller, then, less blood will flow through these vessels.0886

So, what happens is, it is specifically the vasoconstriction of superficial vessels, near the surface of the body.0902

When the blood vessels constrict, there is a decrease of heat loss from these vessels.0913

In contrast, heat triggers vasodilation, so on a hot day, your blood vessels will dilate.0921

That is going to increase the blood flow and allowing for increased heat transfer.0934

So, heat will be lost to the environment through those dilated vessels near the surface of your skin.0943

Vasoconstriction, vasodilation, also play a role in thermoregulation.0948

So, we have talked about vessels. The second component of the circulatory system is the circulatory fluid.0955

In mammals, blood is the circulatory fluid, and it contains a fluid component and a cellular component.0962

The average adult has about 5 liters of blood.0976

So, beginning with the fluid component of blood, that is plasma, and it contains many substances:0991

gases, proteins, hormones, antibodies, waste products being carried away from cells, various components of the plasma.0999

This is the fluid component of blood.1013

The pH of blood is around 7.4, and it is in part maintained by buffers - the buffer system that we will talk about - in the plasma.1016

In addition, so I mentioned proteins, some of the proteins are in the plasma, we are talking about the pH at 7.4.1033

There is a buffer system.1040

There are also clotting factors in the plasma that allow a blood clot to form when someone becomes injured, when they are bleeding.1041

So, that is just an overview of the plasma. We will talk more in a minute about clotting factors and the clotting system.1054

The second component is the cellular component. So, there is the fluid component, which is plasma and cellular components.1063

The major cellular component is red blood cells, so the cellular component: red blood cells and white blood cells.1072

First, red blood cells: the other name for these is erythrocytes.1079

The shape is that these are biconcave discs, so they are, sort of, collapsed in - biconcave discs - and they lack a nucleus.1093

This makes more room for them to do their job. Their job is to transport oxygen, and they contain hemoglobin.1109

The more hemoglobin, the more oxygen they can transport, so by not having a nucleus, there is more room for hemoglobin.1120

Hemoglobin is a protein that contains heme groups, and within the heme groups is iron.1125

And it is the iron that allows hemoglobin to bind oxygen and then, to release the oxygen, to reversibly bind oxygen.1136

We will talk about the structure of hemoglobin and transfer of oxygen in detail.1144

Red blood cells only use anaerobic respiration, so they only undergo anaerobic respiration.1150

And it totally makes sense if you think about it because their job is to transport oxygen.1159

If they were undergoing aerobic respiration, they would actually end up using up the oxygen that they are trying to transport,1164

So, that they are not using up the oxygen, instead, they undergo anaerobic respiration only.1171

Red blood cells have a life span of about 120 days. They live 120 days, and they are produced in the bone marrow.1177

So, the job of the red blood cells is to pick up oxygen in the lungs as the oxygen diffuses from the gas-filled alveoli into the capillaries.1194

They pick up the oxygen. They transport the oxygen into the body tissues.1204

Then, they release the oxygen, and the oxygen diffuses in the body tissues.1208

They also have a role in the transport of CO2, and we will talk about that later, as well.1213

White blood cells are the second cellular component.1220

So, we have the fluid component and the cellular components, which includes red blood cells and white blood cells.1223

White blood cells or WBCs are also called leukocytes.1230

Leukocytes are produced in the bone marrow, and we will investigate these in detail when we talk about the immune system.1235

So, they are produced in the bone marrow, and they have a role in immunity. Their job is to fight infection.1245

If a person has a low white count, they are immunocompromised. They are at risk for serious infections.1251

If a person has high white count, if you test their blood and you say "wow, they have a higher than normal number of white blood cells",1257

that can indicate that they have an infection and that their body is fighting that infection.1264

We raise the number of white blood cells to fight pathogens/invaders.1270

Finally, there is a component that is not cells but actually cell fragments, and these are platelets.1275

Platelets are actually fragments of cells. They are produced in the bone marrow also, and they have a very important function in blood clotting.1282

I am going to talk briefly now also, as we are discussing blood, about blood types.1297

You have probably heard of blood types, or you may even know your blood type: A, B, AB and O and blood types positive and negative.1304

What this is referring to is antigens on the surface of blood cells.1314

If I look at a cell, I look at a red blood cell, and then, I test it; and I say, "OK, it has a particular antigen on the surface",1319

let's call the A antigen for the A blood group, and it is shaped like this, so this person is type A blood.1332

There is another antigen, the B antigen, and the B antigen, let's say, is shaped like this. That person is type B.1342

Type AB is an individual whose cells produce both the A and the B antigens.1356

Finally, type O: O is the absence of the A and B. They have neither, so they are type O.1367

The second system referring to positive and negative is the Rh. It has to do with the Rh factor.1374

So, there is another protein called the Rh factor, and the Rh factor we will say is shaped like this.1380

And if a person has the Rh factor, they are positive, so this individual is A+. If they don't have the RH factor, they are B-.1390

If they have the RH factor, they are AB+. If they do not have the Rh factor, they are O-.1400

Each type can be positive or negative depending on if they have the Rh factor.1406

Now, this is very important when it comes to transfusions because a person's1412

immune system will recognize antigens that are not present in their own blood.1417

So, if somebody is type A and you put B blood or AB blood in their body, they are going to recognize this and attack it.1425

This A+ person, if I transfuse them with B-, they will lyse. They will destroy those cells.1436

If I transfuse them with AB+, they will destroy the cells because they see the B is a foreign protein/antigen.1443

And actually, they are positive, so they will recognize this. They will recognize the A, but they will attack this B.1456

Therefore, for this person, I could give them blood that is A+.1463

I could give them blood that is A- because they just will not have the RH factor. They will not attack because of that.1470

I could also give them O, either positive or a negative.1476

Let's look at this person type B. If I give them something they do not recognize as part of their own antigen system, they will attack it.1484

So, if I give them this A+, they are going to attack it because of the A, and they are going to attack it because of this Rh factor.1493

So, I cannot give them that.1502

If I give them AB, they are going to attack the A part, and if it is positive, they will also attack this. I could give them B-.1504

Could I give them B+? Well, B+, they would have B, and they would also have this Rh factor.1516

Their body would be OK with the B. They would recognize it, but their body will not recognize the Rh factor, so they will attack.1523

One thing is that if you look at O-, it does not have A on it. It does not have B on it, and it does not have the Rh factor.1535

So, it is blank as far as these major antigens. Therefore, O- is the universal donor.1544

I could give it to A, B, AB, positive, negative. There is nothing on here to attack for the major antigens, so therefore, it is the universal donor.1555

Looking at the other way around, no matter what I give AB+, they are going to be OK with it.1566

If I give them A, great, he recognizes the A here. He recognizes the positive.1573

He will not attack it because he has got it.1577

If I give him B- or B+, they will be fine with that. He recognizes it.1580

He has all three antigens, so these all are familiar to the body. They will not attack it.1584

Therefore, AB+ is the universal acceptor.1590

So, what you have on your blood, you recognize as yourself, and you will not attack. What you do not have, you will attack.1596

So, you cannot accept blood from somebody who has got antigens that are not on your own blood.1603

You can accept O-. These are not there, but you cannot accept something that is not on your own blood.1609

So, that is blood groups, and I will explain a little bit about how blood transfusions are done.1617

OK, I mentioned that there are clotting factors in the blood. Blood vessels are lined with epithelial cells.1626

And this lining of epithelial cells is called the endothelium, so the wall of the blood vessel is the endothelium.1634

If a blood vessel is injured, the blood vessel wall, if the endothelium is damaged, platelets are activated.1651

So, damage to the endothelium triggers or activates platelets.1659

When the platelets are activated, they aggregate, and this aggregation forms an initial plug or an initial clot, and this clot starts to staunch the bleeding.1677

This is a plug to decrease the bleeding, and this is just the initial clot.1700

The clot needs to be reinforced, though, by fibrin, and so, it is later reinforced by fibrin.1711

And the fibrin formation is the result of a cascade, so there is a series of events.1723

One enzyme activating another, activating another, that culminates in the formation of fibrin to reinforce that initial plug formed by the platelets.1729

You do not need to know the whole long complicated clotting cascade, but I am going to just talk about the last steps that are important steps.1740

So, if you jump in later in the cascade, one thing you will see is that prothrombin, which is inactive, becomes converted to thrombin.1749

And this is the active form, so I will put a star. That is the active form.1759

Thrombin, then, acts on fibrinogen, which is the inactive form of fibrin, and it activates fibrin. It converts it to its active form, which is fibrin.1766

That fibrin is a filamentous thread-type structure, and it clumps up to form a clot at the site of the damaged vessel wall.1784

It reinforces that initial clot formed by platelets.1793

Now, these are floating around in their inactive form, which prevents clotting from just occurring at random times, which would be disastrous.1797

However, there are also anti-clotting factors that circulate in the blood.1807

So, the clotting cascade does not just occur randomly. It has to be triggered.1813

And platelets release clotting factors. The damaged cells can release clotting factors, and there are clotting factors in the plasma.1818

A deficiency in clotting factors leads to a disorder known as hemophilia, so hemophilia is a result of a deficiency in a particular clotting factor.1828

And individuals with hemophilia are at risk for bleeding.1839

So, even a minor injury could be more serious in an individual with hemophilia because they are not able to stop the bleeding.1846

And they may need to be given these factors.1852

A thrombus is another name for a blood clot, so a thrombus is a blood clot.1856

And when we talk about the heart, we are going to talk about the role that blood clots can play in causing a heart attack.1861

Before we do that, let's talk about the final component of the circulatory system, which is the heart.1870

Amphibians and most reptiles have a three-chambered heart. Mammals and birds have a four-chambered heart, and that is what you see here.1880

It consists of two atria and two ventricles.1889

One side of the heart, the right side, is responsible for pumping the deoxygenated blood into the lungs.1895

The left side of the heart pumps the oxygenated blood to the systems of the body.1904

So, there are two different circuits. This is a double circuit system.1911

There is the pulmonary circuit, and there is the systemic circuit.1916

So, here, we have the right side of the heart, so if the person is facing you, this is the right atrium, the right ventricle, the left atrium and the left ventricle.1927

Let's go through the structure and then, the pathway of the circulation of the blood through the heart.1946

The heart is about the size of fist, and so here, I have the clenched fist, and then, here on the right side, we have the right atrium.1952

Between the right atrium and the right ventricle is a valve. It prevents backflow.1961

So, the blood from the atrium enters the ventricle, and we do not want it flow backwards into the atrium; so this valve prevents that.1968

And this valve is called the tricuspid valve.1974

Here, on the left side of the heart, separating the left atrium and the left ventricle, is another valve called the mitral valve.1981

These valves separating the atria and the ventricles are known as the atrioventricular valves.1997

Another name for the tricuspid valve would be the right AV valve and over here, we have the left AV valve,2008

tricuspid or right AV valve and the mitral valve or the left atrioventricular valve.2021

Now, the ventricles, the walls are thicker than the atrial walls, and in particular, the left ventricle is very strong and very forceful.2028

There are also valves between the heart chambers and the major vessels.2042

So, let's look at these different vessels. Here, if we have the lungs up here, then, blood is going to be oxygenated in the lungs.2050

And it is going to return to the heart via these pulmonary veins, so right here are the pulmonary veins.2062

Blood is coming from the lungs. It has picked up oxygen.2076

It enters the left side of the heart. The left atrium flows into the left ventricle and then, goes to the body.2078

This is actually oxygenated blood, so let me put that in. Let's actually change these.2088

This right here, this is oxygenated blood, and it is leaving the left side of the heart via the aorta.2095

Now, once the blood flows to the body, it is going to drop off its oxygen.2105

It is going to pick up waste products, and this deoxygenated blood is going to return to the heart.2111

It is going to enter the left side of the heart via the superior and inferior vena cava.2117

These two vessels are the vena cava and the superior and inferior vena cava.2123

The superior vena cava drains the upper half of the body: the trunk, the head, the upper extremities.2135

It returns the blood from the upper half of the body. The deoxygenated blood is going to go in here and here.2143

The lower half of the body is drained by the inferior vena cava.2151

The blood will go into the right side of the heart - the right atrium, the right ventricle - and then, to the lungs via this pulmonary artery.2156

This structure is the pulmonary artery, this structure right here.2171

So, tracing this route, let's start in the lungs.2184

The blood is in the lungs. It picks up oxygen, and it returns to the heart via the pulmonary veins.2189

So, this is oxygenated blood, so they are carrying oxygenated blood.2199

Remember, I mentioned that there are some veins and some arteries that are not what you would expect in terms of the type of blood they carry.2203

Most veins contain deoxygenated blood. The pulmonary veins are carrying oxygenated blood from the lungs to the left side of the heart.2210

That blood is going to pass through the left atrium, the mitral valves, enter the left ventricle and then, be pumped out of the aorta to the body.2221

So, it is going to the body from here.2233

Blood goes to the body. Body cells take the oxygen, give the blood the CO2 and waste products.2237

That blood from the body enters the superior and inferior vena cavas. It is deoxygenated blood.2245

It enters the right atrium, passes through the tricuspid valve into the right ventricle and then,2252

is pumped out via the pulmonary artery to the lungs to pick up oxygen again.2261

So, for the right side of the heart, we have the blood being pumped to the lungs,2269

the pulmonary circulation and then, the systemic circulation on the left side of the heart.2274

The left side of the heart pumps the blood to the body.2278

A heart attack or a myocardial infarction is the death of the heart muscles.2284

So, what happens is the aorta carrying oxygen and blood branches of into what is called...2290

It has some branches that come of it that form the carotid arteries.2296

And the carotid arteries supply the heart with blood, with oxygen, with oxygenated blood.2300

So, the carotid artery is the responsible for supplying the heart with oxygen.2306

If the heart does not get enough oxygen, the result is a myocardial infarction, which is damage or death of the heart muscle.2311

Also, it is more commonly known as a heart attack.2324

Now, one risk factor for a heart attack is a disease called atherosclerosis, and this is a condition in which plaque builds up in the arteries.2328

Plaque consists of fatty deposits, and these build up in the walls of arteries.2346

So, if you were looking at a cross-section of the artery, and there were plaque deposits in it, then, these would narrow the artery.2351

If the blue is plaque, and there are these deposits, it is going to narrow the artery, so it is going to decrease the blood flow.2358

Then, when a serious problem can occur, even more serious is if the plaque ruptures.2365

If the plaque ruptures, a piece of it breaks off, and when a piece of plaque breaks off, it actually triggers thrombus formation.2370

So, a clot to form on the plaque, so now, you have this piece of ruptured plaque. It has got a clot on it, and it is floating through the bloodstream.2379

And it is floating through damaged arteries that are already narrow.2391

And what can happen is, the already narrow, now, you have this clump floating through.2395

And it can actually lodge in an artery, block it and cut off the blood supply.2399

If this occurs in the heart, the result is the heart muscle, which needs a lot of oxygen, is not getting oxygen, and it can be damaged. It can die.2404

And that is the pathophysiology underlying a heart attack.2414

We have looked at the anatomy of the heart, the blood flow through the heart, and I just want to emphasize these two circuits.2422

So, the system in mammals is known as double circulation, and some animals have a single circuit.2430

Mammals have a double circuit, so a double circuit system or double circulation.2438

There are two circuits that the blood travels through. I am going to put up here it is the pulmonary circuit, and below is the systemic circuit.2445

And the pressure drops quite a bit when the blood passes through the capillaries. These are capillaries.2457

But, since the blood returns to the heart and is pumped again before it goes to the second set of capillaries, it raises the pressure back up.2464

This is a very effective system in maintaining high pressure throughout.2473

And this is important for mammals because they are very active. They have a high metabolic rate.2479

They need a very good supply of nutrient and oxygen.2483

Right here, we have the right side of the heart, and here is the left side of the heart. This is the lungs up here.2489

What is happening is that the right side of the heart is going to pump the deoxygenated blood into the lungs.2498

And then, in the lungs, gas exchange will occur. The blood will become oxygenated again and then, drain into the left side of the heart.2508

The left side of the heart, the systemic circulation, the left ventricle, will pump blood out through the aorta to the body tissues and organs.2523

And in the capillaries of the body tissues and organs, the oxygen will be dropped off and CO2 will be picked up.2535

So, then, that blood becomes deoxygenated and returns to the right side of the heart, so there are two circuits in the mammalian system.2547

The cardiac cycle refers to the alternation of contractions and relaxation that occurs in the heart.2556

This rhythmic cycle of contracting and relaxing of emptying the chambers during2564

contraction and filling the chambers during relaxation is known as the cardiac cycle.2570

One round, so the cardiac cycle, one cycle equals one round of filling and emptying of the heart chambers or one round of relaxing and contracting.2577

This would be equal to one heartbeat, so the heart beats.2600

What we call one heartbeat is one cycle of the heart contracts,2608

pumps the blood out, empties the chambers, relaxes and allows the chambers to fill again.2613

Some terminology you should be familiar with, systole is the part of the cycle when the heart contracts, so this is called systole.2619

Diastole is the part of the cycle when the heart relaxes.2637

So, during systole, the heart contracts, and blood is emptied. The chambers of the heart are emptied.2649

During diastole, relaxation occurs. The heart chambers fill back up.2659

The average heart rate in an adult, so average heart rate, is about 70 beats per minute, and you might just see it written as bpm- beats per minute.2665

During that minute, if the heart rate is 70, the heart pumps about 5 liters of blood.2683

And this is equal to the volume of blood present in an average-sized adult's body.2692

So, the total volume of blood in someone's body is pumped by the...that amount is pumped by the heart every minute.2697

Blood pressure: the typical blood pressure in an adult is about 120/80 with variations, but this is typical or normal.2707

It is considered normal around in this range.2718

And this top number is known as the systolic blood pressure. This is the pressure in the arteries during the contraction of the heart, so during systole.2721

This bottom number is the diastolic blood pressure, and it is the pressure in the heart when the ventricles relax.2734

Remember that it is the thick walls of the artery that maintain the blood pressure during diastole.2744

During systole, the walls of the arteries are pushed out by the pressure of the blood inside the vessels after the ventricle contracts.2749

When the ventricles relax and are refilling, the arterial walls spring back in, and that helps to maintain the blood pressure.2757

The second thing we are going to talk about now is how the heart rate is set and the maintenance of a regular rate and rhythm in the heart.2767

Heart muscle/cardiac muscle is inherently contractile. It has the inherent ability to contract.2777

If you take some heart muscle, put it in a test tube or an additional lab and looked at it, it contract. It has the ability to contract.2784

However, you cannot have just all these cells contracting at their own rate.2795

The heart would not move in a coordinated manner. It would not be able to pump blood.2800

If that happens, it is called a dysrhythmia, and it can even be life-threatening, so we need a way to maintain the regular coordinated rhythm of the heart.2805

And what the heart has is a structure called the SA node. This stands for sinoatrial node, and this is the heart's pacemaker.2816

It is the heart's natural pacemaker. It sets the heart rate.2830

So, this is a schematic diagram of the heart, but the SA node is located up here in the right atrium, just to give you an idea.2841

And it generates an electrical signal that travels through the walls of the atria.2850

And then, again, this is showing the right and left, sort of, separated out.2859

But in reality, there is the wall of the right and left atria that are next to each other.2863

And there is another structure, and it is called the AV/atrioventricular node.2868

And the signal gets delayed very slightly at the AV node, and what this allows is for the atria to contract slightly before the ventricles.2876

And the reason is you want to have the atria empty so that the ventricles can be filled before the ventricles contract.2886

So, the signal originates at the SA node. It is transmitted through the two atria to the AV node.2894

There is a little delay there while the atria is contracting. Blood flows into the ventricles, and the signal continues on.2901

So, it continues on through the ventricles.2910

And there are structures in the ventricles, the Purkinje fibers and the bundle of His, through which the signal is transmitted.2913

The signal travels from the SA node to the AV node through the bundle of His,2934

through bundle branches and via these structures right here, throughout the ventricles.2943

From the atria, SA node, a little pause in the AV node, then,2951

through structures in the ventricle that transmit the electrical signal so that the ventricles contract.2955

Because these electrical impulses, they are also detected elsewhere in the body.2962

These electrical impulses travel through body fluids and out to the skin, so we can actually detect the electrical impulses of the heart out at the skin.2967

And you have probably heard of a test called an EKG or sometimes ECG. This stands for electrocardiogram.2977

And in this test, what we do is place electrodes on the skin.2986

And that allows us to detect these electrical signals and to assess the functioning of the heart.2993

Now, although the SA node sets the rate of your heart. As you know, your heart rate can be modified.3001

If you are exercising, if your running, your heart rate speeds up. If somebody scares you, your heart rate speeds up.3008

If you are just resting, your heart rate slows down, and this is because the heart rate is affected by the autonomic nervous system.3013

The autonomic nervous system is responsible for involuntary actions.3023

The autonomic nervous system has two major branches to it: the sympathetic and parasympathetic systems.3033

The sympathetic nervous system speeds the heart rate up.3050

This sympathetic nervous system has to do with the fight or flight response, and it helps to speed the heart rate up; so this is increased heart rate.3056

Parasympathetic, if you are at rest, that will help to slow your heart rate down- decreased heart rate.3069

Hormones such as epinephrine or norepinephrine, that we will talk about in the endocrine section, also affect heart rate.3077

Now that we have covered the component of the circulatory system, the flow of blood through the heart, the components of blood,3087

I am going to talk in more depth about how oxygen is transported through the blood as well as how CO2/carbon dioxide is transported through the blood.3094

Remember that red blood cells contain hemoglobin, and hemoglobin is the carrier protein for the oxygen.3103

It is what allows oxygen to be efficiently and effectively conveyed through the blood.3111

Oxygen actually has a low solubility than water.3118

It would be impossible to deliver enough oxygen to body tissues if we had to rely on just dissolving it in plasma.3122

In fact, only a few percent of oxygen is dissolved in plasma. The other 97% is carried by the hemoglobin.3130

Hemoglobin belongs to a group of proteins that are called respiratory pigments.3139

So, another respiratory pigment is hemocyanin.3147

Hemocyanin contains copper, whereas, hemoglobin contains iron, so we are going to talk about hemoglobin in depth.3154

Just to briefly talk about hemocyanin now, hemocyanin is found in the hemolymph of some arthropods and some mollusks.3164

Now, we talked about the fact that arthropods, for example, usually just deliver oxygen via the tracheal system directly to cells.3184

However, there are some arthropods as well as some mollusks that use the hemolymph as an important component to deliver oxygen to cells.3193

And the carrier protein that they use is hemocyanin.3201

The hemocyanin is not contained in cells in the blood. It is just in the blood fluid.3203

And this is a respiratory pigment, and it is actually a bluish-colored pigment.3209

Now, what we are mostly going to talk about is hemoglobin, and that is the respiratory pigment that is found in mammals and that is found in us.3214

Vertebrates use hemoglobin as their respiratory pigment. It is a protein consisting of four subunits.3223

Here is shown 1, 2, 3, 4 subunit. Each subunit contains heme, and within the heme is an iron molecule.3232

Each iron molecule can bind an oxygen, so one hemoglobin molecule can bind four oxygens.3245

Red blood cells are packed full of hemoglobin. Remember they do not even have a nucleus.3254

And they do not have a nucleus, which allows them to have even more room to just pack full of hemoglobin.3259

Each hemoglobin is bound to four oxygen, so red blood cells are very efficient at carrying oxygen from one site to another.3265

Now, this structure is very closely related to the function. Because it has four subunit, it actually allows for an allosteric interaction.3273

Remember that an in an allosteric interaction, what occurs in one part of a molecule can affect the conformation, can affect another part of the molecule.3283

And in fact, hemoglobin demonstrates cooperative binding, so hemoglobin demonstrates cooperative binding of oxygen.3292

What happens is the binding of oxygen to the first subunit causes a conformational change that makes it easier for the second subunit to bind oxygen.3305

That makes it easier for the third subunit, and it makes it easy for the next subunit.3315

So, it is toughest to get that first subunit to bind, but once that is bound to oxygen, binding is easier for the remaining subunits.3321

Now, this can be understood a little bit further by looking at a curve called the oxygen-hemoglobin dissociation curve.3331

And this is something you should be familiar with and that you should understand.3341

So, we are looking at this graph, and this graph has a sigmoidal or S shape.3346

The graph shows the percent saturation of hemoglobin with oxygen, so the percent of hemoglobin that is bound by oxygen.3353

And it is comparing it versus the partial pressure of oxygen in millimeters of mercury.3367

Over here, we have very low partial pressure of oxygen, and it is starting out at no hemoglobin being bound to oxygen.3373

This curve is actually flatter at very low partial pressures of oxygen, and then, the curve gets steep. It flattens out again.3385

So, exaggerating it some more, it would be an S-shaped curve.3394

Now, this has to do with that structure of hemoglobin with the four subunits and the cooperative binding.3397

At very low partial pressures, most of the hemoglobin is unbound to oxygen, and if I raise the oxygen a little bit, yes, some of the hemoglobin will bind.3404

But it is difficult because it is the binding of that first subunit, and it is difficult for that to occur.3415

Getting that first subunit bound is difficult, so a lot of the hemoglobins are not bound at all, and then, some of them start to bind a very first subunit.3421

However, if I raise the oxygen partial pressure even more, I take it up to, say, 20 here, I see that the curve is very steep.3430

And that is because once that first subunit is bound, it is easier for the second.3438

When the second is bound, it is easier for the third, so once we get past the first subunit binding, the curve becomes much steeper.3443

So, in this physiological range where most of our body tissues are, if you increase, say, I am here at 20,3452

and about 35% hemoglobin saturation with oxygen, if I increase to 30, that percent saturation goes to 60.3461

So, all this increase in binding of hemoglobin to oxygen by this slight increase in the partial pressure of oxygen.3475

At very low partial pressures, the curve is not steep. In the middle, the curve is steep, and then, the curve flattens out.3485

And the reason it flattens out is saturation has been reached.3491

I can add more and more and more oxygen, but the problem is there is no more hemoglobin sites left to bind oxygen.3495

So, at a certain point, adding oxygen is not going to increase the saturation. It is maxed out.3504

So, this is the shape of the curve.3509

And you should understand that this sigmoidal shape has to do with the four subunits of hemoglobin and the cooperative binding.3511

Now, low partial pressures of oxygen would be in active tissue.3520

So, if you look at your muscles when you are working out, they are using up a lot of oxygen.3527

Because they are undergoing aerobic respiration, they need to make a lot of ATP, a lot of energy.3532

So, they are going to use up oxygen that have low partial pressure of oxygen.3537

In the lung, there will be a high partial pressure of oxygen.3541

And the affinity of hemoglobin for oxygen can change based on conditions.3548

And this allows the hemoglobin to deliver oxygen where it is needed and pick up oxygen where it is needed.3555

One condition that affects the affinity of hemoglobin for oxygen is pH.3565

So, if we look at pH, a lower pH decreases the affinity of hemoglobin for oxygen.3573

A lower affinity can be looked at as the hemoglobin will let go of oxygen more readily.3593

Hemoglobin lets go of oxygen more easily, so what does this mean?3601

First of all, think about where pH is low. Recall that pH is going to be lower in metabolically active tissues.3610

I discussed this is the respiratory lecture, and I am going to discuss it again in a minute in more detail.3621

But for right now, just recall that in blood cells, carbon dioxide and water combine to form carbonic acid, which forms bicarbonate and hydrogen ion.3626

So, in a muscle or a body tissue that is very metabolically active, it is using oxygen, it is generating CO2,3640

this reaction will be pushed to the right with the result of increased hydrogen ions and therefore, decreased pH.3647

In metabolically active tissues, the pH is low. The result is what we call a shift to the right of this curve, so this curve is going to change.3659

At low pH, this will be the curve: shift to the right.3681

This shift to the right, under certain conditions, is called the Bohr effect or the Bohr shift.3688

Let's look at what this means. Let's say I looked at here a PO2 of about 30, and I say "Alright".3700

At a PO2 of 30, I go up to my first curve, and hemoglobin saturation is about 60%.3714

Now, the curve has shifted to the right. At the same partial pressure of oxygen, 30, hemoglobin saturation is only 40%.3723

That means 20% has been let go. Instead of 40% or instead of 60% saturation, we only have 40%, so all of this has been let go.3736

Looking at it this way, it allows the hemoglobin to let go of oxygen or deliver oxygen to where it is needed.3752

And the reason for this is that the presence of these hydrogen ions changes the conformation of the hemoglobin molecule and gives it a lower affinity.3760

It does not bind as well to the oxygen.3768

This is how the red blood cells know "let go", or it helps them to let go of the oxygen.3770

So, when a red blood cell travels to the body, it arrives at a tissue that is in need of oxygen, and the pH there is low.3777

It will decrease its affinity for oxygen and let go of the oxygen and then, pick up CO2, go back to the lung.3786

In the lung, pH is higher, so pH is back up at 7.4; so in the lung, this curve is going to shift back to the left.3793

And what is going to happen in the lung, then, is at any given PO2, the hemoglobin is going to have a higher affinity for oxygen.3806

And it is going to grab oxygen, which is exactly what you want in the lung.3815

In the lung, you want a higher affinity of hemoglobin for oxygen, and so it will grab oxygen.3818

In the tissues of the body, you want a lower affinity of hemoglobin for oxygen so that it will drop the oxygen off.3825

If you look at curves for maternal and fetal hemoglobin, you will also see the differences in affinity here of hemoglobin for oxygen.3834

So, if I looked at a fetal hemoglobin curve, I am going to put it in black here, versus maternal, if this is fetal hemoglobin and the blue is maternal,3846

what the fetus needs to do is it needs to take oxygen from the mother to survive. That is where it has to get its oxygen.3859

So, at any given PO2, if I look here at 40, what I will see is that the maternal hemoglobin binds, say, for 75% saturated.3865

But, the fetal hemoglobin is 90% saturated, so the fetal hemoglobin has a higher affinity for oxygen than the maternal hemoglobin.3876

Before going on, I also want to note that another factor that can cause a shift to the right, I said, it is caused by low pH.3886

Another thing that occurs in active tissue is the temperature increases.3896

If you are running, the temperature in your muscles is going to increase.3900

So, increased temperature also triggers the shift to the right because it is another signal that that tissue needs oxygen.3903

There is another hemoglobin-binding molecule called myoglobin.3914

Myoglobin has only one subunit. It does not have the four subunit structure.3919

So, it does not demonstrate this sigmoidal shape. It is just a linear graph for hemoglobin binding.3926

However, one thing about myoglobin is that it has a higher affinity for oxygen than hemoglobin, and because of this, it binds oxygen very effectively.3931

And there are marine mammals like seals that can dive and stay under water for 30 minutes even hours.3942

And what allows these mammals to do it when humans certainly cannot do this is that these mammals have large stores of myoglobin in their muscles.3950

So, stores of myoglobin allow certain marine mammals to remain submerged for long periods.3960

And it provides a store of oxygen for these mammals during that time.3980

Alright, we have talked about oxygen transport, and now, I am going to talk more about CO2 transport.3992

So, the blood is traveling through the capillaries. It arrives at the body tissues.3999

It drops off its hemoglobin, and it picks up the CO2 from those cells.4006

There is a small amount of the CO2 that just dissolves in the plasma and is transported that way, so that is one way that transport occurs.4011

A second way that CO2 is transported is it binds to hemoglobin.4020

A CO2 can actually bind with the amino group on hemoglobin peptide, but these are not the major ways a CO2 is transported.4026

The major way that oxygen is transported is binding within the hemoglobin molecule.4035

But, for CO2, most transport is actually in the form of bicarbonate ion.4039

So, what happens is a red blood cell goes to the body tissues, drops off its oxygen, so here is a red blood cell.4046

The oxygen and this is the body tissues, and there is the capillary wall, of course.4054

It has diffused past the capillary wall into the fluids running the tissue and then, into the cells.4063

So, the oxygen is going to diffuse out, be dropped off to the body tissues. Then, carbon dioxide from the tissue is going to enter the red blood cell.4068

In the red blood cell, this CO2 will recall the reaction where it is going to combine with water. It is going to form carbonic acid.4087

And this reaction is reversible and then, bicarbonate ion and hydrogen ion.4102

The conversion of CO2 and water to carbonic acid, H2CO3, is catalyzed by the enzyme carbonic anhydrase.4110

So, the result here is that CO2 is taken up, and reaction occurs that converts this CO2 plus water eventually to bicarbonate and hydrogen ion.4130

So, what happens to this? Well, the bicarbonate can leave the cell and enter the plasma, and it becomes part of the plasma buffering system.4147

It serves as a part of the buffering system and also as a means of transporting this carbon dioxide in the bloodstream.4160

How does this serve as a buffering system? Well, let's say that the pH is too high.4171

So, if the pH is too high, this means we need more hydrogen ion.4180

What can happen, then, is this reaction will go the opposite direction. Actually, no, it will go in the forward direction.4187

If we need more hydrogen ion, then, more CO2 will combine with water to form carbonic acid. That is H2CO3.4197

And so, CO2 will combine with water to form carbonic acid, and that will, then, go on to form bicarbonate and hydrogen ion.4216

So, this is if the pH is too high.4241

Now, let's say the blood pH is too low. We need to decrease this level of hydrogen ion.4243

So, now, bicarbonate and hydrogen ions will react to form carbonic acid, which will, then, dissociate into carbon dioxide and water,4252

thus, lowering the concentration of hydrogen in the blood and raising the pH back up.4265

You can see this reaction going one way or the other helps to buffer the blood and keep the pH within a narrow range.4272

Once this blood travels to the lung, what is going to happen in the lung is that CO2 is going to diffuse into the lung.4281

So, the CO2 is going to go into the lung, which is going to pull this reaction back to the left.4292

As we draw the CO2 off, hydrogen ions will combine with bicarbonate to form carbonic acid and then, carbon dioxide and water.4300

So then, more carbon dioxide can diffuse into the lung.4313

This reaction also helps to deliver the CO2 into the lung once the red cells and the plasma reach the lung, OK?4318

Important points are that the majority of carbon dioxide is actually transported in the blood in the form of bicarbonate ion.4330

You should also be familiar with this reaction in which CO2 and water combine to eventually form bicarbonate4340

and hydrogen ion and the fact that this allows for a buffering system in which to decrease the level of4347

hydrogen ions as needed if the pH is too low or increase the hydrogen ion concentration if the pH is too high.4357

OK, now, we are going to talk about some examples using the material from the circulatory system.4368

Example one: trace the pathway of blood through the circulatory system by placing the structures below in the correct order.4376

Begin with the oxygen-rich blood as it leaves the lungs to return to the heart.4384

We are starting in the lungs, so how is the oxygen-rich blood from the lungs brought back to the heart via the pulmonary veins?4391

So, this is a vein or veins that actually carry oxygenated blood.4404

We start out in the lungs. From the lungs, blood travels via the pulmonary veins, so I have used this one.4409

Oxygenated blood returns to the left side of the heart, so that would be first the left atrium.4422

The blood will pass through the mitral valve into the left ventricle.4430

When the left ventricle contracts, it pumps blood into the systemic circulation, and that occurs through the aorta.4437

The blood is, then, going to go into the body tissues, drop off oxygen, pick up CO2 and then, enter veins to return to the heart.4449

In the upper part of the body, the superior vena cava drains this deoxygenated blood into the heart.4460

In the lower half of the body, it is the inferior vena cava, so we are just going to put "vena cava".4468

So, this blood is now deoxygenated. It is going to drain into the right atrium.4475

We used right atrium. We used vena cava.4487

Then, from the right atrium, the blood will go to the right ventricle.4491

It is deoxygenated, so it is going to be pumped from the right ventricle through the pulmonary artery to the lungs to complete the cycle.4495

So, this is the correct order: lungs to the pulmonary veins to the left atrium, left ventricle,4510

aorta, vena cava, right atrium, right ventricle and then, finally, pulmonary artery.4517

Example two: which veins carry oxygenated blood?4526

Well, from what we just discussed, you know that the pulmonary veins carry oxygenated blood from the lungs to the heart.4531

What is the name of the structure that functions as the pacemaker for the heart? That is the sinoatrial node, very commonly known as the SA node.4553

What are the cell fragments in the blood that function in clotting called? These are the platelets.4568

These are cell fragments found in the blood.4576

Describe the role of vasodilation and vasoconstriction in thermoregulation.4584

Recall that vasoconstriction is constricting of the blood vessels, so the diameter becomes smaller.4591

In vasodilation, blood vessels dilate. Their diameter becomes larger.4597

In the cold, vasoconstriction of superficial vessels occurs.4602

The result is decreased blood flow through those vessels, and then, the result is decreased heat loss via heat transfer through the skin.4619

Heat triggers vasodilation of the superficial vessels. The result is going to be a decrease in the vessel diameter or an increase.4636

Excuse me. Vasodilation is going to increase the diameter of the vessels.4654

The result is going to be increased blood flow through those vessels and increased heat loss through4660

heat transfer from the superficial vessels out in the environment, so this will cool the body down.4668

The result, then, increased heat loss, the body cools.4676

The opposite occurs with vasoconstriction. There is less heat loss through the skin, through the superficial vessels, and the result is the body warms.4681

And this helps us maintain our body temperature.4690

Hemoglobin, this dissociation curve is shown below. Sketch the expected curve following an increase in pH.4695

Think about what happens, the conditions, when pH is increased.4704

pH is decreased in active tissues. These are tissues that are using a lot of oxygen and generating CO2.4710

And what we want to happen is decreased hemoglobin affinity for oxygen.4721

So, the result is if pH is decreased, we get the shift to the right that we talked about.4728

However, in the lungs, pH is going to be increased. That would be an example of higher, higher pH.4736

And what we want to do is increase the affinity of hemoglobin for oxygen because we want the hemoglobin to take the oxygen from the lungs.4743

Therefore, there is going to be a shift to the left, so the curve is going to be shifted to the left.4757

So, taking a look at this just to check, shift to the left is correct.4768

At a partial pressure of, say, 30, in my original curve, there is about 55% hemoglobin saturation.4773

In my new curve at a partial pressure of 30, there is actually a saturation of more like 90%. This is a difference of 35.4789

That much more oxygen was grabbed. It was picked up, which is what you want.4806

So, the answer is that there would be a shift to the left, so the curve would look roughly like this.4810

That concludes this lecture on circulation.4816

Thank you for visiting Educator.com.4819

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