1. Warm-Up
Look up the definitions of the Central Nervous System vs. the Peripheral Nervous System. Compare these two types of nervous systems.
What is a neuron? Draw and label its 3 main parts.

2. Warm-Up Draw and label the parts of a neuron.
Describe saltatory conduction.
Explain how a nerve impulse is transmitted across a neuron.

3. Warm-Up What happens at the synapse?
Choose 1 neurotransmitter. Describe its action.
What is the role of the following structures in the human brain?
Brainstem
Cerebellum
Cerebrum
Corpus callosum

4. Neurons, Synapses, and Signaling
Chapter 37

5. You must know The anatomy of a neuron.
The role of active transport in establishing the membrane potential of a neuron.
The mechanisms of impulse transmission in a neuron.
How depolarization of the presynaptic cell leads to the release of neurotransmitters.
The events at the synapse that allow a presynaptic neuron to communicate with the postsynaptic cell.

6. Organization of the Nervous System
Central nervous system (CNS) = brain & spinal cord
Peripheral nervous system (PNS) = nerves throughout body
Sensory receptors: collect info from world
Eg. Rods and cones in eye, skin receptors, chemoreceptors, thermoreceptors
Neuron = functional unit of nervous system

7. Types of Neurons Sensory neurons: info from body sensors  CNS
Interneurons: connect sensory + motor neurons, or local connections between brain + spinal cord
Motor neurons: CNS  body (effectors = muscles, glands)
Nerves = bundles of neurons
Contains motor neurons +/or sensory neurons

8. Sensory neurons
Interneurons
Motor neurons

9. Types of Neurons

10. Neuron = dendrite + cell body + axon

11. Neuron cell body: contains nucleus & organelles
dendrites: receive incoming messages
axons: transmit messages away to other cells
myelin sheath: fatty insulation covering axon, speeds up nerve impulses
synapse: gap between 2 neurons
neurotransmitter: chemical messengers sent across synapse
Glia: cells that support neurons
Eg. Schwann cells (forms myelin sheath)

12. Schwann cells and the myelin sheath

13. BioFlix: How Neurons Work

14. Membrane Potential: difference in electrical charge across cell membrane

15. The Na+/K+ pump (using ATP) maintains a negative potential inside the neuron.

16. Action potentials (nerve impulses) are the signals conducted by axons
Resting potential: membrane potential at rest; polarized
Na+ outside, K+ inside cell
Maintained by sodium-potassium pumps
Voltage-gated Na+ channel = CLOSED
Nerve impulse: stimulus causes a change in membrane potential
Action potential: neuron membrane depolarizes
All-or-nothing response
Na+ channels open
K+ channels open
Na+ enters cell
K+ leaves cell

19. Conduction of an action potential

20. Nerve Impulse Animation

21. Saltatory conduction speed: 120 m/sec
Saltatory conduction: nerve impulse jumps between nodes of Ranvier (unmyelinated gaps)  speeds up impulse
Saltatory conduction speed: 120 m/sec

22. Saltatory Conduction

23. BioFlix: How Synapses Work

24. Molecular Mechanism of Synaptic Function
HHMI Animation (1:09 min)
Molecular Mechanism of Synaptic Function

25. Signal Transmission

26. Neurotransmitter released at synapses Axon (presynaptic cell)  Synaptic cleft  Dendrite (postsynaptic cell)  Cell Response

27. Neurotransmitters
Chemicals released from vesicles by exocytosis into synaptic cleft
Diffuse across synapse
Bind to receptors on neurons, muscle cells, or gland cells
Broken down by enzymes or taken back up into surrounding cells
Types of neurotransmitters:
Excitatory: speed up impulses by causing depolarization of postsynaptic membrane
Inhibitory: slow impulses by causing hyperpolarization of postsynaptic membrane

29. Examples of Neurotransmitters
Acetylcholine (ACh): stimulates muscles, memory formation, learning
Epinephrine: (adrenaline) fight-or-flight
Norepinephrine: fight-or-flight
Dopamine: reward, pleasure (“high”)
Loss of dopamine  Parkinson’s Disease
Serotonin: well-being, happiness
Low levels  Depression
GABA: inhibitory NT
Affected by alcohol

30. Nervous System Disorders
LSD/mescaline – bind to serotonin and dopamine receptors  hallucinations
Prozac – enhances effect of serotonin by inhibiting uptake after release
Morphine, heroin – bind to endorphin receptors  decrease pain perception
Viagra – increase NO (nitric oxide) effects  maintain erection
Alzheimer’s Disease (AD) – develop senile plaques, shrinkage of brain tissue

31. Mouse Party

32. Mouse Party Group Poster: Drug Neurotransmitter(s) Involved
Action of Drug
Summary Illustration: