Excitatory Neurotransmitter

Question 1

when an excitatory neurotransmitter is released from a nerve cell at a
synapse does it automatically cause an action potential?

Answer 1

no

Question 2

If not, what does it cause?

Answer 2

It causes a depolarization to occur. A depolarization is when the Resting
Potential becomes MORE POSITIVE. It is a small positive charge.

Question 3

What specific ion channel is opened by an excitatory neurotransmitter?

Answer 3

An excitatory NT causes a depolarization by opening gated sodium channels, letting
sodium in. This means an excitatory NT’s receptor is actually a gated sodium channel.

Question 4

How CAN an action potential be caused by an excitatory neurotransmitter?

Answer 4

Two (or more) depolarizations must occur together and add together to produce an action
potential. When added, the two depolarizations must reach -55 mV in order to create
the action potential. -55 mV is the threshold, the minimum amount of depolarization
needed to create an Action Potential.

Question 5

8. b. In the left graph image below, the two arrows (with E1) represent two
   separate releases of excitatory neurotransmitter. The three picture
   images on the right show (& describe) “A,” “B,” and “C” of that graph.

Answer 5

Temporal summation of depolarizations, or two
depolarizations overlapping in time, to create an action
potential.