Question 1

Which region of the neuron is primarily responsible for receiving incoming signals from other neurons?

Accepted Answer

Dendrites

Question 2

What is the main function of the sodium-potassium pump ($\mathrm{Na^+/K^+}$ ATPase) in maintaining the resting membrane potential?

Accepted Answer

It pumps three $\mathrm{Na^+}$ ions out of the cell and two $\mathrm{K^+}$ ions in, maintaining concentration gradients.

Question 3

A neuron is described as 'excitable.' What does this mean in terms of its membrane potential?

Accepted Answer

It can generate and propagate electrical signals in response to stimuli.

Question 4

Which of the following best describes the change in membrane potential during depolarization?

Accepted Answer

The inside of the membrane becomes less negative, moving toward zero and above.

Question 5

What is the primary effect of myelin on axonal conduction?

Accepted Answer

It increases the speed of nerve impulse transmission by insulating the axon.

Question 6

Which type of ion channel opens in response to the binding of a neurotransmitter?

Accepted Answer

Chemically gated channel

Question 7

During the absolute refractory period, why can a neuron not trigger another action potential?

Accepted Answer

Voltage-gated $\mathrm{Na^+}$ channels are open and cannot reset.

Question 8

Which equation best represents the relationship between voltage, current, and resistance in neurons?

Accepted Answer

$V = I 	imes R$

Question 9

A patient has a mutation that causes their neurons to be less permeable to $\mathrm{K^+}$ ions. What effect would this have on their resting membrane potential?

Accepted Answer

The resting membrane potential would become less negative (closer to zero).

Question 10

Which of the following is true regarding graded potentials?

Accepted Answer

They decay in amplitude with distance from the stimulus.

Question 11

What is the main difference between continuous and saltatory conduction?

Accepted Answer

Saltatory conduction occurs at the nodes of Ranvier and is much faster.

Question 12

If the extracellular concentration of $\mathrm{Na^+}$ increases, what is the most likely effect on the neuron’s ability to depolarize?

Accepted Answer

Depolarization would be enhanced due to a greater influx of $\mathrm{Na^+}$.

Question 13

Which of the following statements about the axon hillock is correct?

Accepted Answer

It is the region where action potentials are typically initiated.

Question 14

A neuron receives multiple subthreshold stimuli in rapid succession. What phenomenon allows these stimuli to combine and potentially trigger an action potential?

Accepted Answer

Temporal summation

Question 15

Which of the following best explains why action potentials are unidirectional?

Accepted Answer

The refractory period prevents the backward opening of $\mathrm{Na^+}$ channels.

Question 16

During repolarization of the action potential, which ion movement is primarily responsible for returning the membrane potential toward resting values?

Accepted Answer

$\mathrm{K^+}$ efflux

Question 17

Which of the following would most likely increase the conduction velocity of an action potential along an axon?

Accepted Answer

Increasing the thickness of the myelin sheath

Question 18

A neuron’s cytoplasm contains more $\mathrm{K^+}$ and less $\mathrm{Na^+}$ than the extracellular fluid. What does this indicate about the ion distribution across the plasma membrane?

Accepted Answer

There is a charge separation that contributes to the resting membrane potential.

Question 19

Which of the following best describes the role of voltage-gated $\mathrm{Na^+}$ channels during the generation of an action potential?

Accepted Answer

They open rapidly during depolarization, allowing $\mathrm{Na^+}$ influx.

Question 20

A patient presents with symptoms of multiple sclerosis, a disease that damages myelin in the central nervous system. Which of the following would most likely be observed in their neurons?

Accepted Answer

Decreased speed of action potential propagation due to impaired saltatory conduction

Neurophysiology: Structure and Function of Neurons

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