Which of the following is the most direct result of depolarizing the presynaptic membrane of an axon terminal?
a. Voltage-gated calcium channels in the membrane open
b. Synaptic vesicles fuse with the membrane
c. Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft
d. An EPSP or IPSP is generated in the postsynaptic cell

Question

Which of the following is the most direct result of depolarizing the presynaptic membrane of an axon terminal?

a. Voltage-gated calcium channels in the membrane open

b. Synaptic vesicles fuse with the membrane

c. Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft

d. An EPSP or IPSP is generated in the postsynaptic cell

Accepted Answer

Hello everyone here We have a question asking during the deep polarization of the membrane, what causes the decrease in the difference in voltage between the inside and outside of the neuron? A ions cannot flow through the sodium ion channels on the neurons membrane because they are closed. This is incorrect. During membrane deep polarization, the gated sodium ion channels on the neurons membrane open. And this allows the positively charged sodium ions into the cell. So A. Is incorrect. B. When the sodium ion channels open, the sodium rushes towards the outer part of the membrane, this is incorrect, it rushes into the cell. See the negative charges rush towards the inner part of the membrane. This is incorrect. It is rushing into the cell D. When this gated sodium ion channels open, the sodium present outside rushes into the cell. That is correct. And as the sodium rushes in the internal charge of the nerve decreases, causing the difference in voltage inside and outside the neuron to decrease. So our answer here is d thank you for watching. Bye.

Verified video answer for a similar problem:

Key Concepts

Depolarization of the Presynaptic Membrane

Voltage-Gated Calcium Channels

Synaptic Vesicle Fusion