lecture 4

Question 1

What are the basic stages of synaptic connections

Answer 1

at resting potential (in a cell body) a stimulus produces graded potential (in the axon hillock) that may generate an action potential (in the axon) that triggers synaptic activity to the postsynaptic cell

Question 2

What does ACh do for chemical synaptic transmission

Answer 2

ACh binding sites open chemically gated Na+ channels for graded depolarization

Question 3

What are the events of cholinergic synapse

Answer 3

1. Action potential opens CA+ voltage-gated channel
2. Ca+ diffuse into the axon terminal and trigger ACh release from synaptic vesicles ( in pre-synaptic axon terminal) by exocytosis
3. ACh diffuses across synaptic cleft and opens Na+ channel for graded depolarization
4. Depolarization ends with ACH being broken down into acetyl and choline by ACHE
5. Axon terminal reabsorbs choline and synthesizes more ACh using it

Question 4

What is synaptic transmission at NMJ

Answer 4

• Excitatory and absolute
• no axon hillcock
• no EPSP/IPSP summation

Question 5

What is Summation

Answer 5

the temporal or spatial addition contractile force or neural stimuli