1. How do nerves transmit signals and communicate?
Neuron Physiology
How do nerves transmit signals and communicate?

2. Neurons Selectively permeable to Na+ and K+
At rest, membrane is polarized; K+ inside cell, Na+ outside cell

3. Sodium channels open and allow Na+ to diffuse into the cell

4. Inside of cell temporarily more positive than the outside
Depolarization

5. Potassium channels open allowing K+ to flow out of cell
Outside of cell
Potassium channels open allowing K+ to flow out of cell
Inside of cell

6. Negative charge is restored on inside of membrane
Repolarization

10. Video from Kahn Academy

11. Action Potential
Action Potential = an electrical event occurring when a stimulus is applied allowing for Na+ to enter the neuron and reverse the polarity of the cell

12. Action Potential Localized event Self-propagating
Moves in one direction
Impulse Animation

13. Impulse travels down axon
Reaches terminal branches – synaptic knobs

14. Within synaptic knobs are synaptic vesicles
Contain neurotransmitters (ex: acetylcholine)
Synaptic vesicles fuse with membrane
Release contents into synaptic cleft

15. Neurotransmitters diffuse across the gap and attach to receptors on receiving neuron.
Permeability of membrane changes
Na+ diffuse into receiving cell
Impulse continues
Neurotransmitter removed or destroyed. Transmission Across a Synapse Animation

16. Neurotransmitters
Acetylcholine = responsible for control of muscle tissue
Histamine = responsible for symptoms of allergic reactions
Dopamine = helps to provide feelings of enjoyment
Seratonin = helps to regulate mood

17. Saltatory Conduction (role of myelin) Anatomy of a nerve Nerve Impulse
You Tube Videos
Saltatory Conduction (role of myelin)
Anatomy of a nerve
Nerve Impulse