Week 7 - Transmission of the Signal at Synapses (steps)

Question 1

step 1

Answer 1

when the action potential reaches the axon terminal, the electrical charge opens calcium channels

Question 2

step 2

Answer 2

calcium, in turn, causes the tiny vesicles containing the neurotransmitter chemical (acetylcholine) to fuse with the axonal membrane

Question 3

step 3

Answer 3

the entry of calcium into the axon terminal causes porelike openings to form, releasing the neurotransmitter (acetylcholine) into the synaptic cleft

Question 4

step 4

Answer 4

the neurotransmitter molecules diffuse across the synaptic cleft and bind to receptors on the membrane of the next neuron

Question 5

step 5

Answer 5

if enough transmitter is released, a graded potential will be generated
- eventually an action potential (nerve impulse) will occur in the neuron beyond the synapse

Question 6

step 6

Answer 6

the electrical changes prompted by neurotransmitter binding are brief

• the neurotransmitter is quickly removed from the synapse either by reuptake or by enzymatic activity
• transmission of an impulse is electrochemical
• —- transmission is down neuron is ELECTRICAL
• —- transmission to next neuron is CHEMICAL