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Dr. Carleen Eaton

Dr. Carleen Eaton

The Nervous 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 Mwongera Mwarania on January 29, 2018

I have two questions:

1)My mental picture of saltatory conduction is like a electric spark (the electrical impulse travelling down the nerve) "jumping" over the insulated section of a wire (the mylienated section of the nerve) to the bare section wire (nodes of Ravier) and because of it, the conduction is fastened. Is this imagery correct?

2) I know that you have explained the speed of conduction is faster in thicker nerves because there is less resistance. I am using your lessons to prepare for MCAT. The revise MCAT has an integrative approach in examining concepts. Using physics electricity principles, can you please how action potential conduction fit in with the said physics principle?

1 answer

Last reply by: Tope Adedolapo
Mon Apr 3, 2017 3:55 PM

Post by Tope Adedolapo on April 3, 2017

Thank you for your lecture. However, I have a question.

Around 22:03 you mentioned that potassium is negatively charged. It should be positively charged. My question is does this affect any of your later concepts presented here?

1 answer

Last reply by: Mwongera Mwarania
Mon Jan 29, 2018 9:53 AM

Post by jessica chopra on March 2, 2013

Where can I find a lecture on all the senses and how they work, for example how the eye works?

1 answer

Last reply by: Dr Carleen Eaton
Mon Nov 12, 2012 6:37 PM

Post by bo young lee on November 2, 2012

where do i find the human body structure, and human body system

1 answer

Last reply by: Dr Carleen Eaton
Tue Apr 3, 2012 5:55 PM

Post by reena chainani on April 3, 2012

Do motor neurons only act on effector cells and not other neurons?

1 answer

Last reply by: Dr Carleen Eaton
Wed Jun 1, 2011 11:49 PM

Post by Daniela Valencia on May 31, 2011

Dr Carleen Eaton,

I would like to let you know that you are an amazing teacher, you have no idea how much your videos have helped me with my intensive studying for the PCAT test, you explain everything very clear.. no need to use the text book.

Thank you!!!

0 answers

Post by Dr Carleen Eaton on March 25, 2011

Correction at 52:28:

The correct spelling for the word describing the membranes surrounding the brain and spinal cord is "meninges"

The Nervous System

  • Neuron structure: The cell body contains the nucleus and organelles. Dendrites extend from the cell body and receive incoming stimuli. The axon hillock is the region where the action potential is initiated. The impulse is carried away from the cell body by the axon.
  • The myelin sheath is produced by Schwann cells and acts as an insulator, increasing the conduction of the electrical signal.
  • The Nodes of Ranvier are segments of the axon that are not myelinated.
  • An action potential is triggered when a stimulus causes sodium channels to open, thus depolarizing a cell. If the cell reaches its threshold potential, voltage-gated sodium channels will open, resulting in a rapid, large depolarization of the cell.
  • The voltage-gated sodium channels close quickly and voltage-gated potassium channels open, repolarizing the cell.
  • During the absolute refractory period following an action potential, another action potential cannot be initiated.
  • Depolarization of the synaptic terminal membranes by an action potential stimulates the opening of voltage-gated calcium channels. The subsequent increase in calcium concentration in the synaptic terminal causes the exocytosis of neurotransmitters.

The Nervous 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 Nervous Systems 0:28
    • Nerve Net
    • Flatworm
    • Cephalization
    • Arthropods
    • Echinoderms
  • Nervous System Organization 3:40
    • Nervous System Organization Overview
    • Automatic Nervous System: Sympathetic & Parasympathetic
  • Neuron Structure 6:57
    • Cell Body & Dendrites
    • Axon & Axon Hillock
    • Synaptic Terminals, Mylenin, and Nodes of Ranvier
  • Pre-synaptic and Post-synaptic Cells 10:16
    • Pre-synaptic Cells
    • Post-synaptic Cells
  • Types of Neurons 11:50
    • Sensory Neurons
    • Motor Neurons
    • Interneurons
  • Resting Potential 15:14
    • Membrane Potential
    • Resting Potential: Chemical Gradient
    • Resting Potential: Electrical Gradient
  • Gated Ion Channels 24:40
    • Voltage-Gated & Ligand-Gated Ion Channels
  • Action Potential 30:09
    • Action Potential Overview
    • Step 1
    • Step 2
    • Step 3
    • Step 4
    • Step 5
  • Action Potential Transmission 39:04
    • Action Potential Transmission
    • Speed of Conduction
    • Saltatory Conduction
  • The Synapse 44:17
    • The Synapse: Presynaptic & Postsynaptic Cell
    • Examples of Neurotransmitters
  • Brain Structure 51:57
    • Meniges
    • Cerebrum
    • Corpus Callosum
    • Gray & White Matter
    • Cerebral Lobes
    • Cerebellum
    • Brainstem
    • Medulla
    • Pons
    • Midbrain
    • Thalamus
    • Hypothalamus
    • Ventricles
  • The Spinal Cord 1:00:29
    • Sensory Stimuli
    • Reflex Arc
  • 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

Transcription: The Nervous System

Welcome to Educator.com.0000

In this section of animal physiology, we will be focusing on the nervous system.0002

And the nervous system provides a mechanism for the body to receive and send information.0007

And this can be external stimuli that is being received such as sounds and smells or internal information such as temperature,0013

blood pressure that allows the body to coordinate functions and maintain homeostasis.0022

We are going to start out by talking about different types of nervous systems and then, focus in detail on the human nervous system.0031

The simplest nervous system is called a nerve net.0038

And you will recall in the section in diversity of life, I described a nerve net as being found in cnidarians like jellies and Hydra.0042

So, a nerve net is simply a diffused group of interconnected nerve cells. There is no central nervous system.0056

If you look at a simple animal but with a more advanced nervous system than the nerve net, that would be the nervous system of a flatworm.0067

So, the flatworm has longitudinal nerve cords and a pair of ganglia, so nerve cords and ganglia.0079

Recall that ganglia are clusters of nerves, and in the flatworm, these are at the anterior end of the organism.0096

And they allow for processing of sensory input.0109

This gets us to a related point in the evolution and development of the nervous system and that is the concept of cephalization.0113

Recall that in bilaterally symmetrical animals, cephalization developed.0122

And this is the development of a head end in which sensory organisms are clustered or concentrated.0129

Sensory organs are concentrated here and ganglia to process this information, then eventually, in more advanced animals a brain.0141

To give you just examples of an overview of nervous systems and a couple other groups of0155

animals before we go on to talking about vertebrates and particularly humans- arthropods.0160

Arthropods have well-developed sensory organs.0168

They have eyes. They have organs that allow for smell, antennas for touch and even ears in some species.0178

Some have ganglia. Other arthropods actually have brains.0186

Echinoderms such as sea stars have a less well-developed nervous system. They have, recall, a nerve ring with cords that radiate out into their arms.0193

Next, we are going to go ahead and focus in on the vertebrate nervous system.0215

I am going to start with an overview of the organization, discuss the neuron and transmission of nerve impulses and then, revisit the central nervous system0222

in more detail once we have covered the terminology that you need to understand the structure and function of the central nervous system.0233

Here is the nervous system overall, and there are two major divisions.0241

The central nervous system consists of the brain and spinal cord, and the peripheral nervous system is everything else.0245

The PNS can be further divided into two major systems: the autonomic nervous system and the somatic nervous system.0255

The somatic nervous system is responsible for voluntary activities, so voluntary activities such as when you walk or talk or turn your head.0265

Those are all under the control of the somatic nervous system.0279

By contrast, the autonomic nervous system is responsible for involuntary activities.0284

The heart, the GI tract and the endocrine organs are all regulated by the autonomic nervous system.0291

Some systems actually split off into a third division, which is the enteric nervous system, and this is regulation of the GI tract.0297

Instead, they are just putting it under the autonomic system, so you may encounter that.0308

So, nervous system: central versus peripheral.0314

Peripheral is divided into autonomic and somatic, and then, autonomic has two further divisions: the sympathetic nervous system and the parasympathetic.0317

The sympathetic nervous system is responsible for the fight or flight response.0329

Recall that the fight or flight response results in an increase in heart rate, respiratory rate, glucose. Blood is shunted to the skeletal muscles.0335

So, the idea is that if there is a threat like a person is chasing you or something is about to fall on you and you have to run away really quickly,0350

your body triggers this giving you the oxygen, the glucose, the energy, everything you need to either fight or run away.0360

The opposite is parasympathetic. This is often described as rest and digest.0373

With the fight or flight, we see an increase in the heart rate, increase blood pressure, increase in respiration. Blood is shunted to the skeletal muscles.0381

With the rest and digest, things return to calmer. There is a decrease in the heart rate, decrease in the respiratory rate. Blood is shunted to the GI tract.0395

Now we have an overview, we are going to focus on the functional unit of the nervous system,0418

which is the neuron, beginning with the structure of the neuron.0424

And then, we will talk about the way that signals are transmitted along the neuron and from one neuron to another neuron or cell.0427

Beginning with the cell body, the cell body contains the nucleus and organelles for the nerve cell.0437

Extending from the cell body are projections called dendrites.0448

Dendrites receive incoming stimuli, and there are various types of stimuli.0454

It depends on the type of neuron. In the eye, the dendrites are specialized to receive could be light.0467

A stimulus on your skin, there are pain receptors, different touch receptors.0476

The stimulus that is received, it can be specialized.0482

Or the stimulus might just be another neuron that is synapsing on this neuron and stimulating this neuron to transmit the signal.0486

So, it could be an outside stimuli or another cell synapsing on this one.0496

This section right here, leading away from the cell body, is called an axon hillock.0501

And this is the region where the action potential that we are going to talk about or impulse that0509

transmits the signal from the dendrites here along down this axon, so this is the axon.0515

The action impulse is initiated here, action potential initiated here.0525

This is the axon. We will come back to this in a second.0540

And then, here at the end of the axon are the synaptic terminals.0542

We are going to look at a close up view of this later, but the neurotransmitter is released from the synaptic terminals.0546

Some nerve cells have myelinated axons, so what they have is what is called a myelin sheath that encases much of the axon.0562

Myelin in the peripheral nervous system is produced by Schwann cells.0579

Now, there are segments that are unmyelinated even on a myelinated neuron, and these are called nodes of Ranvier.0589

When I talk about action potentials, you will learn how the action potential really appears to skip from one node to the other in a myelinated neuron.0600

So, right now, I am just focusing on structure, and then, we will talk about function.0609

Here, you can see several nerve cells together, and these two nerve cells are synapsing on this nerve cell giving it input.0619

As I said, the neurotransmitters are released from the synaptic terminal here. They can, then, diffuse to the postsynaptic cell, give it input.0631

So, what I want you to understand here, is that these cells are called presynaptic cells.0644

Here, we have the synapse, this connection between one cell and another, and then, here, I have a postsynaptic cell.0655

Now, the nerve cell does not always synapse on another nerve cell. In fact, the nerve cell might synapse on a muscle cell.0671

So, what happens, then, is that the nerve cell is giving the muscle cell a signal to contract or inhibiting contraction.0681

Or a nerve cell can also synapse on an endocrine gland. It could, then, cause the endocrine gland to release a particular hormone.0693

There is communication not just obviously between one nerve cell and another but between the nerve cell and other systems of the body.0701

There are three groups of neurons.0712

The first group are the sensory neurons, and the sensory neurons receive information from the environment.0714

So, they receive input in the form of...it could be sound. It could be light, touch, smell.0729

And then, they transmit the input to the central nervous system to the brain,0742

to the spinal cord and to the brain for processing so that sensory input is received.0751

For example, when you look, your optic nerve is receiving that input of light, but it is your brain that interprets the image.0762

So, processing occurs in the central nervous system.0772

Information within the body is also collected: changes in blood pressure, changes in their stretch receptors in the GI tract.0775

So, the internal environment is monitored as well through the sensory neurons.0785

The second group of neurons are the motor neurons, and these transmit impulses to the muscle. They can, then, stimulate the muscle to contract.0792

Some motor neurons, as I mentioned, synapse on endocrine glands, so they might transmit to an endocrine gland stimulating a secretion of a hormone.0811

The cells that motor neurons act on...motor neurons act effector cells, so an effector cell could be a muscle for example.0824

You may have heard of Lou Gehrig's disease, also known as ALS, and this is a motor neuron disease.0840

It is degeneration of the motor neurons resulting in muscle atrophy and weakness throughout the body.0858

Finally, interneurons: interneurons connect sensory and motor neurons, so the input is being received by a sensory neuron.0866

Then, that signal may be transmitted to an interneuron which will, then, convey the information to a motor neuron.0886

These are also located in the central nervous system, the brain and the spinal cord.0895

And this is just giving you a very simple example, but the interactions between all of the different neurons are very complex.0901

But, in general, there are these three types, and this is how they interact.0909

Next, we are going to talk about how signals are transmitted by the nervous system.0915

And to understand that, you need to understand a concept called resting potential.0920

Just starting out talking about membrane potentials, a membrane potential is the difference in the electrical charge across the cell membrane.0926

So, if I have a cell and I am going to draw the cell here as a tube like if I am looking at the axon, the long axon membrane as a cylinder here,0936

there is a difference in electrical charge between the inside of the cell and the outside of the cell.0952

It is a result in a difference in concentration of ions between the inside and the outside of the cell.0959

The resting potential is the membrane potential of a neuron that is not conducting a signal, so that is why it is the resting potential. The cell is at rest.0967

So, the resting potential - this is the resting potential - is around -70 mV in the neuron.0978

And it is the result between the difference in sodium and potassium ion concentration inside and outside of the cell.0989

The concentration of sodium ions outside of the cell is much higher than inside of the cell, so lots of sodium outside, not so much inside.1000

The situation with potassium is the opposite. Lots of potassium inside the cell relative to the outside of the cell.1015

This gradient is maintained a couple of ways.1028

First of all, there is the sodium-potassium pump that I have mentioned elsewhere in the course.1031

What this pump does is it hydrolyzes ATP and uses the ATP for active transport of sodium out of the cell and potassium into the cell.1038

Three sodium are transported into the cell per two potassium.1049

Excuse me, correction. Three sodium are transported out of the cell per every two potassium transported into the cell.1061

So, when one ATP is hydrolyzed, the result will be per ATP hydrolyzed.1075

One ATP is hydrolyzed. That transports three sodiums out and two potassiums in.1082

So, here is this pump right here, and it is sending three sodiums out for every two potassiums in.1089

And this is active transport because these are being transported against their concentration gradients.1098

So, concentration of sodium outside the cell is much, much greater than sodium inside.1108

What the sodium wants to do is diffuse into the cell or not diffuse actually because it is an ion, but it wants to enter the cell. It wants to enter the cell.1119

It cannot though unless it goes through a channel.1128

Therefore, to get it out, you need to transport it against its gradient.1132

The concentration of potassium outside the cell is much, much lower than potassium inside the cell.1139

What potassium wants to do is it wants to leave the cell. To get it to enter the cell requires this active transport.1150

So, this maintains this concentration gradient.1158

Now, what happens is since these are charged, there also ends up being an electrical gradient.1161

So, this is a chemical gradient where we have lots of high sodium concentration out and high potassium concentration inside- chemical gradient.1170

But, this creates an electrical gradient, and let me talk about how this is created and maintained.1181

Well, for every three sodium out, only two potassium are pumped in. This is a net loss of +1 charge from the cell.1195

So, for every turn of the pump, one unit of positive charge is lost overall, a net loss of positive charge.1209

As a result, the inside of the cell ends up with a negative charge relative to the outside of the cell.1218

And this difference in charge ends up giving a membrane potential of -70 at rest.1232

The other issue here is that sodium channels...there are sodium channels.1245

And the sodium wants to go down its concentration gradient at the end of the cell.1252

The problem is these are mostly closed, so sodium channels are mostly closed. Meanwhile, many potassium channels are open.1258

So, what happens is some potassium can leave the cell, and that is a loss of more positive charge to make the cell negative.1275

Now, to balance this, chloride wants to follow so that the positive sodium leaving the negative chloride is going to go out with it.1284

And it will balance out in terms of charge. However, chloride channels are closed.1295

So, the positive charge sodium cannot really enter the cell.1301

The negatively charged chloride cannot leave the cell, but potassium, which is positively charged can leave the cell.1306

The result is we have more positive charge leaving.1315

We already have this in balance to the sodium potassium pump where we have more positive charge leaving the cell than coming in.1319

Now, we have more potassium leaving, and that causes this negative charge inside the cell relative to the outside.1324

What will happen is that there will be a net loss of potassium until the pull of the chemical gradient1334

of potassium is exactly counterbalanced by the negative charge pulling the potassium back in.1343

So, there are two forces acting on potassium.1352

There is a chemical gradient, which is drawing potassium out of the cell because potassium wants1354

to go down its concentration gradient to outside the cell where potassium is lower concentration.1362

So, the chemical gradient pulls - you can think of it as pulls - potassium out.1371

However, the electrical gradient, because potassium is negatively charged, draws potassium in, and these two are working in opposition.1379

And so, potassium will leave the cell until there is an equilibrium reach where the concentration gradient is no longer sufficient of potassium1391

- the chemical gradient - to oppose the attractive force, the negative charge drawing the positively charged potassium in.1402

That point of equilibrium occurs at about -70 mV, and that is the resting potential.1409

So, resting potential is a result of the selective permeability of the cell membrane for ions,1417

the fact that potassium channels are open but sodium and chloride are not.1425

And the resting potential is also maintain by the sodium-potassium pump.1431

What we say is that this cell is polarized. When we say that it has a resting potential, we say that it is polarized.1439

And I am going to talk about depolarization and hyperpolarization and repolarization.1450

And we are starting out with the cell that is polarized because of this difference in electrical charge compared with the inside versus the outside of the cell.1454

Now, I am talking about sodium channels and chloride and potassium channels, and these are a different type of channel that I am about to talk about.1466

I am going to talk again about sodium and potassium channels but a different type than I just discussed.1474

And these other types of channels are called gated ion channels, and these are key to understanding the action potential.1481

So in addition to the sodium and potassium channels I discussed, there are these channels that are gated.1489

Gated, meaning a stimulus triggers the opening or closing of an ion channel, so, gated means stimulus triggers the opening or closing of a channel.1498

And some of the channels that I talked about could involve some type of stimulus opening or closing.1520

But, I really want to focus on voltage-gated ion channels for the action potentials.1525

Voltage-gated channels would open or close due to a change in membrane potential.1532

So, these are regulated, the opening and closing of them is regulated by a change in membrane potential.1540

There are also what is called ligand-gated channels.1552

And in lagan-gated ion channels, opening or closing is triggered by the binding of a molecule to the channel.1556

So, ligand-gated, the stimulus would be binding of a ligand opens or closes the channel.1562

Extremely important in action potentials is voltage-gated ion channels.1578

These are sodium channels and potassium channels whose opening is controlled by changes in potential.1589

So, there are two types you need to be aware of.1597

The ones in orange are the sodium- voltage-gated sodium channels. The ones in purple are voltage-gated potassium channels.1600

This is a cell membrane, and this is the inside of the cell. Here is the outside of the cell.1610

Recall that outside the cell, very high relative to the inside of the cell concentration of sodium.1617

Inside the cell, the situation...and this is going to curve around the cell membrane1628

Inside the cell of the opposite, I have relatively high potassium, relatively low sodium concentration.1636

Opening these voltage-gated sodium channels causes a massive influx of sodium into the cell.1658

So, sodium is going to open up. Tons of these will open up once during an action potential, and the result is going to be sodium enters the cell.1665

When that positive charge enters the cell, it is going to make the cell less negative.1677

The cell was at -70 mV. If you put tons of sodium into the cell, it will go up to -50 and -40 and then, +10 and on up.1684

So, sodium enters the cell when these are open, and the result is the cell becomes depolarized; and I am going to put these all in context in just a minute.1694

Now, what is happening here actually these arrows should be going the other way. Let me go ahead and correct that, so correction there.1712

Now, what is happening is that since the concentration of potassium is very high in the cell relative to outside,1723

the potassium wants to go down its concentration gradient and leave the cell, and what that is going to do is cause positive charge to leave the cell.1731

When potassium leaves the cell the result will be the membrane potential will become more negative.1743

When the membrane potential becomes more negative, if it drops below the resting potential baseline, then, we say it is hyperpolarized.1765

Sometimes what is happening is that the membrane potential became plus negative due to depolarization.1774

And all the potassium is doing by coming back into the cell is resetting it to baseline, is repolarizing.1781

The thing you should understand is that sodium enters the cell. That causes the cell to become more positive inside.1788

That is depolarization.1794

When potassium leaves the cell, the cell becomes more negative inside.1797

That is positive charge leaving, and the cell becomes repolarized or even hyperpolarized.1802

An action potential transmits the signal along the axon of the neurons.1811

So, an action potential is also known as an impulse, and it is a large change in the membrane potential.1815

As you can see, this change down here is a quick increase where the membrane potential becomes more positive.1823

And then, it drops rapidly and becomes more negative and returns to its baseline.1832

So, here, at -70 is the resting potential, and I will give you an overview; and then, we will talk about what happens at each step.1837

As this is increasing, what we have here is depolarization. The cell is becoming depolarized until it reaches the peak.1849

Here, the cell is repolarizing, so it is repolarization.1866

It actually undershoots and goes past baseline, so the repolarization really tends to be a little more precise. It would be right around here.1875

And then, this segment here, when it passes rest, so repolarization is occurring as it is dropping, dropping, dropping and then, hyperpolarization.1888

The cell is depolarizing, becoming more positive, repolarizing, but then it shoots past the resting potential and then, hyperpolarizes briefly.1912

And then, it goes back to the baseline.1925

Let's look at what happens during each section here.1928

First, the cell is at rest. There is no stimulus.1931

Then, a stimulus excites the neuron and causes entry of sodium into the cell, and that can occur from a stimulus. It could be another neuron.1937

It could be light. It could be sound.1954

Some kind of stimulus excites the neuron, and it is going to cause sodium to enter the cell here.1956

Remember that when sodium enters the cell, sodium is positively charged.1962

So, these positive charges entering the cell are going to cause the membrane to become less negative.1969

It is going up, kind of, creeping up towards what is called threshold.1974

So, the stimulus causes the entry of sodium into the cell and causes some depolarization.1983

If the stimulus is strong enough, enough sodium will enter the cell that the cell reaches threshold.1993

If the membrane potential, the cell membrane, reaches threshold potential...let me put this right here, threshold.2004

If the cell membrane reaches threshold potential, then, the voltage-gated sodium channels open.2021

When the voltage-gated sodium channels open, that is going to be a massive influx of positive charge into the cell.2042

Here, you get some entry. Hopefully, it is enough to get you up to threshold, get things going.2050

But at this point, this is what we call all or none response that either you are going to get to threshold, and these are all going to open;2056

or you are not going to get to threshold, and none of these voltage-gated sodium channels will open.2069

If they do open though, there is going to be a very fast change in the membrane potential.2073

It is going to be more and more positive until it reaches a certain peak, and action potential is a stereotypic size and shape.2079

Even if you put a super strong stimulus, this is still going to peak at, say, 35.2086

It is not going to peak at 50, or it is not going to make the graph wider somehow or end up more hyperpolarized.2093

The size and shape are always going to be the same for a cell.2098

What is going to change though, is if there is a stronger stimulus, the action potentials will become more frequent, not larger.2101

They do not become larger.2113

Alright, now, the voltage-gated sodium channels have opened, big influx of sodium into the cell.2115

However, they quickly close. They quickly close.2123

So, then, the next thing that happens is sodium channels close, and here, voltage-gated potassium channels open.2127

Because right now, the cell has become depolarized.2149

The inside of the cell is now relatively positive and to end this action potential, we need to get back to the resting state.2154

Here, we have sodium rushing into the cell, then, the sodium channels close. The potassium channels open.2162

And potassium is going to go down its concentration gradient and leave. Potassium leaves the cell, so potassium rushes out of the cell.2172

During depolarization, we get sodium in.2184

During repolarization, potassium rushes out taking that negative charge with it, bringing the membrane potential back down, down to the negative range.2188

However, potassium continues to leave the cell not just until it hits this resting potential, but it does what is called an undershoot.2200

And at that point, there is hyperpolarization.2212

The cell has not just repolarized, it is actually gone past its hyperpolarized, and this section of the curve is called the refractory period.2217

And you cannot initiate another action potential during that time or during the latter part of it.2230

It is harder to initiate a potential, although, you maybe able to initiate it.2237

The reason that you cannot initiate an action potential during the refractory period is that the sodium channels remain closed.2241

And then, what happens is the sodium potassium pumps get to work and return things to normal, to baseline.2255

They cause return to the resting potential.2266

Initially, we had a stimulus triggering some entry of sodium into the cell.2273

So, the membrane potential becomes less negative, and then, if it hits threshold, the membrane potential's threshold is right around -50,2278

the voltage-gated sodium channels will open, and then, there will be a massive influx of sodium into the cell.2290

It will peak. The sodium channels will close, and then, the potassium channels will open.2299

There will be a massive influx or outflow of potassium from the cell. The membrane potential drops.2305

It undershoots. The cell is hyperpolarized.2313

That is the refractory period, a time during which an action potential cannot be initiated at all, or at certain points, it can be, but it is more difficult.2316

And then, as the sodium-potassium pump gets all this sodium back out and potassium back in, puts things back to where they were,2327

the cell will return to its resting potential state, and then, another action potential can be initiated.2336

The next thing is to talk about how action potentials are transmitted along the axon, and I am going to just draw a schematic.2346

Let this represent the axon.2357

A stimulus initiates the action potential at first, but then, that action potential initiates an action potential in a nearby segment of the membrane,2364

which initiates an action potential in the next segment and then, in the next segment.2377

This is often compared to having a row of dominos, and you push the first domino. That is the initial stimulus.2381

And then, that domino causes the next one to fall and the next one and the next one, and that is how an action potential is propagated along the axon.2387

So, remember at rest, what we are going to have is a relatively negative charge inside the axon and a relatively positive charge outside the axon.2396

The action potential comes along and switches that, so now, we end up with a positive charge inside and a negative charge outside.2409

The depolarization of the cell that causes this action potential is, then, going to cause depolarization in this nearby segment,2421

which will initiate the action potential there, which will open all those sodium channels and cause major depolarization, and that action potential gets going.2433

Meanwhile, this one is recovering from the previous. It has become repolarized, and it is returning to its resting state.2447

And now, it is going to be back at resting potential.2455

So, one action potential initiates another and so on along the cell, and in that way, the signal is propagated along the axon.2459

Now, the speed of conduction of an action potential is dependent on a couple of factors, so speed of conduction.2480

Larger diameter axon conducts more quickly. Myelinated axon conducts more quickly.2493

So, the larger the diameter, the less resistance there is. That action potential would be conducted more quickly along.2531

The other thing that can help is insulation.2539

Recall that Schwann cells produce myelin and the myelin sheet around the axon.2542

We have this long axon, and if it is myelinated, that serves us an insulator.2549

Let's say this is myelinated, and in between the myelinated segments are the nodes of Ranvier.2565

Conduction works like this on myelinated axons.2577

What happens is the electrical current moves quickly through these myelinated sections and then, initiates an action potential in the node of Ranvier.2582

The only place that there are the voltage-gated ion channels in a myelinated cell are in the nodes of Ranvier.2591

They are not exposed here, or they are not found in myelinated segments.2600

The current is going to connect quickly along these myelinated segments.2607

And then, when it gets to a node of Ranvier, it is going to initiate an action potential.2610

Current will travel through here, initiate an action potential and so on.2614

And so, it seems like what is happening is the signal is just jumping from one node to another to another.2617

And that is called saltatory conduction where what we have is saltatory conduction.2623

It is the action potential skips from one node to the next rather than being transmitted right from2630

one section to the next, to the next, to the next, as it would if the myelinated sheath were not there.2650

Alright, we talked about conduction of the action potential along the axon.2656

The dendrites receive a signal. The action potential is initiated at the axon hillock, and then, it is propagated along the axon.2662

Here, we have a presynaptic cell and postsynaptic cell, and this communication between the two that is the synapse.2672

So, the action potential is traveling along here. It gets to the synaptic terminal, so this end-region is the synaptic terminal.2687

Finally, we have this space right here. This is called the synaptic cleft.2702

Alright, the action potential travels along the axon. It gets to the synaptic terminal, and it causes the release of neurotransmitters.2711

In these vesicles are neurotransmitters, and they are already packaged in vesicles. They are ready to go.2721

And when the action potential comes along and depolarizes the synaptic terminal,2729

these vesicles will fuse with the cell membrane and release neurotransmitters into the synaptic cleft.2735

Action potential travels to the synaptic cleft - excuse me - synaptic terminal. This causes exocytosis of these little packets of neurotransmitter.2747

The neurotransmitters diffuse across the synaptic cleft to receptors on the post synaptic cell where they bind to the receptor and trigger a response.2774

So, what you should note is that when we were talking about action potentials,2809

we were talking about the communication or a transmission of an electrical system.2813

Here, the electrical signal has been converted to a chemical signal.2819

So, electrical signal of the action potential is now, converted to the chemical signal via the neurotransmitter.2826

To add a little bit more detail, calcium plays a role in mediating the release of neurotransmitters.2835

What happens is that depolarization of the presynaptic cell at the synaptic terminal causes voltage-gated calcium channels to open.2842

So, depolarization results in the opening of voltage-gated calcium channels, then, there are many of these channels in the synaptic terminal.2862

And then, here, we are going to have calcium enter the cell through these channels.2878

And it is the calcium, the increase in calcium level that triggers the release of the neurotransmitters.2885

So, increased calcium in the synaptic terminal triggers the release of the neurotransmitters.2895

The neurotransmitter, then, can do one of several things.2923

It can either just diffuse a way, diffuse out of the synaptic cleft because the neurotransmitter, if it just stayed here,2927

it would continue to stimulate the postsynaptic cell and generate a response from it.2934

And instead of it just sitting here and continuing to do that, it is going to either diffuse away, so removal of neurotransmitter from the synaptic cleft.2940

It can diffuse away. It can be broken down by an enzyme, or it can be taken up by the presynaptic cell.2951

So, in some cells, the neurotransmitter is taken back up, repackaged and then, reused by the presynaptic cell, so it is recycled.2968

In others, it just diffuses away, and then, there are esterases- enzymes that breakdown neurotransmitter.2978

And the response that this neurotransmitter binding to the cell will cause depends on the particular cells involved and the neurotransmitter.2986

The result could be to stimulate the cell or inhibit the cell, and that differs from situation to situation.2996

Some examples of neurotransmitters: one is acetylcholine; serotonin is another; dopamine.3006

There are many kinds of neurotransmitters.3026

Acetylcholine acts at the neuromuscular junction, so it is released by a neuron and then, stimulates the contraction of a muscle cell.3029

There is an enzyme - just to give you an example - called acetylcholinesterase.3039

So, you just take acetylcholine and add esterase, acetycholinase - excuse me - acetylcholinase, and that will breakdown the acetylcholine in here.3043

So, again, just to give you a review before we move on, the action potential is propagated along the axon.3060

It causes the depolarization of the synaptic terminal resulting in the opening of voltage-gated calcium channels, and that causes the influx of calcium.3071

The increase in calcium concentration triggers the fusion of vesicles containing neurotransmitters with the cell membrane.3088

Those neurotransmitters are released into the synaptic cleft.3096

They diffuse over to the post synaptic cell where they can bind receptors and illicit a response.3101

So, that is how the electrical signal is converted into a chemical signal at the synapse.3109

Now, as I said, we are going to revisit the topic of the organization and structure of the nervous system now that you3117

have the terminology that you need to understand focusing on the central nervous system, the brain and the spinal cord.3123

The brain, just giving you an overview, it has many twists and convolutions, and those increase the surface area of the brain.3130

The brain and spinal cord are covered with connective tissue called meninges.3140

So, meninges is a connective tissue that covers the brain and spinal cord, and you may have heard meningitis; so that is inflammation of the meninges.3148

This is a schematic showing you the major parts of the brain.3171

The cerebrum is the forebrain, and it is divided into left and right hemispheres; so there are left and right hemispheres.3178

So, we are looking at a side view, so we are just seeing one hemisphere, and there is a thick band of tissue called the corpus callosum.3193

And the corpus callosum connects the two hemispheres. It is very important because it allows for communication between the two hemispheres.3202

The surface of the brain, of just the overall structure is consisting of grey matter.3219

So, the surface of the cerebrum is grey matter in the brain, and deeper in is the white matter.3228

Grey matter consists of cell bodies, dendrites and some unmyelinated axons.3239

Deeper in below the surface is the white matter, which consists of bundles of myelinated axons.3256

Alright, in the cerebrum are voluntary activities and thought or cognition, so voluntary activities. This is what allows you to consciously think.3267

Sensory input is processed here.3283

Speech, emotions, personality, motivation, memory, your ability to think, reason, plan and make decisions is all located in the cerebrum.3286

And for example, if somebody gets an injury or a tumor to the frontal lobe, an area of the cerebrum called the frontal lobe,3303

then, what can happen is there might be a personality change and because this is an area that controls personality.3311

So, somebody who is very laid back and, kind of, calm and collected before might become more volatile or agitated, act differently than before.3321

The cerebrum is divided into four lobes, so cerebral lobes.3332

It is divided into left and right hemispheres and the lobes, which are the frontal lobe, the parietal lobe, the occipital lobe and the temporal lobe.3343

The next section of the brain, structure of the brain we are going to talk about is the cerebellum.3360

The cerebellum is very important in coordinating movement.3367

And if a person has an injury to the cerebellum, they might walk in a certain, kind of, staggering off-balanced way, and it is called ataxia.3373

Cerebellum is very important for balance and in the coordination of movements.3385

The brain stem controls some of the basic functions of life, and the brain stem consists of three parts: the medulla, the pons and the midbrain.3390

Recall that - let's over here write this out - the medulla in the respiratory section,3411

I talked about how the medulla is one of the structures responsible for regulating breathing, so regulates breathing.3417

It also regulates the heart rate and the amount of constriction that blood vessels have, vasoconstriction versus vasodilation.3426

I will just put vasoconstriction, so constriction or non-constriction of blood vessels.3438

The next structure in the brain stem is the pons.3444

And the pons is responsible for relaying information from the cerebrum to the cerebellum- relays info from the cerebrum to the cerebellum.3447

It also helps in the regulation of breathing.3465

The midbrain plays a role on various functions, for example vision, auditory function, so various different roles and some of the sensory functions.3475

Oops, thinking about test, this should be midbrain not midterm.3497

OK, next, structure that you should be familiar with is the thalamus.3502

The thalamus, which lies outside the cerebellum and brainstem, relays sensory information to the cerebrum.3510

So, it relays sensory information to the cerebrum. The information passes through the thalamus, goes up into the cerebrum.3520

We talked in detail about some of the functions of the hypothalamus when we talked about the endocrine system.3537

And we are going to talk about a couple more right now.3544

So, remember that the hypothalamus, located right around here, regulates the anterior pituitary. It also has a very important role in homeostasis.3548

It helps with the regulation of temperature, hunger, thirst, so a very important function of maintaining homeostasis, regulates the anterior pituitary.3561

And recall that the hypothalamus also produces oxytocin and ADH hormones stored in the posterior pituitary.3575

There are cavities in the brain called ventricles, and these are cavities that contain cerebrospinal fluid.3591

Arterial blood is filtered to form CSF or cerebrospinal fluid.3610

And what the cerebrospinal fluid does is it supplies the brain with substances such as nutrients, and it also helps to cushion the brain, OK?3616

So, these are some of the major structures found in the brain.3625

The spinal cord serves as the connection between the peripheral nervous system and the brain.3630

Here, it is the opposite set up in terms of grey and white matter as it was in the brain. Here, the white matter in the spinal cord is outside.3639

It is on the surface, and grey matter is deeper. It is on the inside.3648

I will just say outside and inside or surface and deeper.3655

So, there is sensory input. There are sensory stimuli, and that is sent to the spinal cord.3663

And then, it goes up to the brain, and then, there is a response that goes out via the motor neurons.3672

Remember, there are different types of neurons, and the signals travel into the3688

spinal cord via sensory neurons and then, out of the spinal cord via the motor neurons.3694

Now, many most actions are initiated in the brain.3702

However, there are reflexes for when we need to do a really fast response, and the injury could happen if we had to wait for the brain to process it.3706

So, there are reflex arcs, and the best way to understand this is through example.3716

Reflex arcs are actions that are initiated by the spinal cord without even having to wait for the brain to figure out a response.3722

Let's say that you touched a hot iron. The information from the receptors in your hand are sent to the spinal cord via the sensory neurons.3731

So, the sensory neurons bring the information to the spinal cord. This sensory neuron will, then, synapse on the motor neuron.3748

Motor neuron causes a response. The sensory neuron will bring the information to the spinal cord.3770

The motor neuron will stimulates the response, and that response would be is to stimulate certain muscles to contract so that you draw your hand away.3786

Interneurons maybe involved, as well. Interneurons recall, they draw the connection between the sensory and the motor neurons,3796

So, it might, then, go sensory to an interneuron and then, motor neuron, and part of what the interneurons can help do is also sent inhibitory responses.3810

So, to grab your hand away certain muscles need to contract.3825

Those need to be stimulated, and others need to relax so that they do not oppose that movement.3828

And the interneuron will help to send out that inhibitory response.3833

The knee jerk response is another reflex arc, so when the doctor taps just below your kneecap, that causes a stretch in the tendon.3837

And then, what ends up happening is that it gets sent to your spinal cord, and it creates a contraction that will cause you to kick out your leg.3847

And that is just a reflex. It is not controlled in your brain.3858

Now, at the same time this is happening, the interneurons may also help to send the information up to your brain about you have just touched3862

something hot, and more responses might follow initiated by your brain; but that initial very fast response is part of a reflex arc.3868

Now, we are going to go on and review the nervous system by doing some practice questions.3877

Example one: what are the two divisions of the autonomic nervous system and describe the function of each.3882

The two divisions of the autonomic nervous system are one the sympathetic nervous system, and the other is the parasympathetic.3890

The sympathetic is responsible for the fight or flight response.3900

This is a response that is going to result in an increase in heart rate, increase in respiration, increase in blood sugar, blood sent to the skeletal muscles,3910

the pupils will dilate, so pretty much a response that allows a person to run away or fight, somehow respond to a threat.3929

Parasympathetic is often called, known as the rest and digest response. It returns things back down to calm.3938

Blood is shunted to the GI tract, so you can digest your food, which you would not want to waste energy digesting your food if you run away from something.3946

So, The heart rate will decrease, respiratory rate will decrease, so the opposite response from the sympathetics.3957

Which structure in the brain is responsible for regulating breathing and heart rate?3970

That is the medulla. Although, the pons does also help to regulate breathing.3976

Example two: describe the events at the synaptic terminal that lead to the release of neurotransmitters.3984

Remember that we have this synaptic terminal, and then, we have our postsynaptic cell with receptors.3991

And what happens is action potential travels along the axon, and it depolarizes the cell membrane in the synaptic terminal.4000

That triggers the opening of these voltage-gated calcium channels- voltage-gated calcium channels open.4021

As a result, calcium enters the cell, so calcium enters the cell.4038

The increase in calcium, increase in the calcium concentration causes exocytosis of a neurotransmitter4045

of these neurotransmitters already packaged in vesicles waiting to fuse with the cell membrane.4066

They fuse with the cell membrane and are released and then, can bind to receptors on the postsynaptic cell.4071

Which voltage-gated ion channels are open during section one of the action potential below? So section one, I am going to mark as this section.4082

Which voltage-gated ion channels are open section two? Section two, I am going to mark as this section right here.4097

We see a typical action potential, and during this section one, what is happening is the depolarization is occurring.4108

And depolarization is the result of the opening of sodium channels, voltage-gated sodium channels.4116

Positively charged sodium ions enter the cell membrane potential, more and more positive.4129

It peaks, and then, here, during section two which is repolarization, voltage-gated potassium channels open, and the sodium channels closed.4136

The result is that the potassium is going to leave the cell, bringing negative charge with it4148

and cause the cell to repolarize and even hyperpolarized as the positive charge leaves the cell.4157

Example four: label the following structures on the figure below starting with axon.4167

Axon carries the action potential away from the cell body, so the action potential goes along. It goes down the axon.4173

Cell body: the cell body is where the nucleus and organelles of the neuron are located.4184

Axon hillock is where the action potential is initiated.4191

If the stimulus is strong enough, the incoming stimulus then, an action potential will be initiated here and propagated away from the cell body along the axon.4196

Dendrite: dendrites receive an incoming stimulus. They project out from the cell body.4207

So, we did axon. We did dendrite, cell body, axon hillock and finally, synaptic terminals here at the end of the axon.4218

And these are the site of the release of neurotransmitters.4227

So, that concludes this lesson on the nervous system here at Educator.com.4232

Thank you for visiting.4237

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