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 actively transports three $$\mathrm{Na^+}$$ ions out of the cell and two $$\mathrm{K^+}$$ ions into the cell.

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 (more positive) relative to the outside.

Question 5

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

Accepted Answer

Chemically gated channel

Question 6

During the generation of an action potential, what event occurs at the threshold potential (approximately $$-55 to$$ $$-50 mV$$)?

Accepted Answer

All voltage-gated $$\mathrm{Na^+}$$ channels open due to positive feedback.

Question 7

Which statement about graded potentials is correct?

Accepted Answer

They decay in amplitude with distance from the stimulus.

Question 8

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 9

Which of the following best explains why the inside of a resting neuron is negative relative to the outside?

Accepted Answer

Large anionic proteins are trapped inside the cell and the membrane is more permeable to $$\mathrm{K^+}$$ than to $$\mathrm{Na^+}.$$

Question 10

A patient presents with a genetic disorder that affects the voltage-gated $$\mathrm{Na^+}$$ channels in neurons, causing them to remain open longer than normal. What is the most likely effect on the action potential?

Accepted Answer

The neuron will be unable to repolarize, leading to prolonged depolarization.

Question 11

Which equation correctly represents Ohm's Law as applied to neuronal membranes?

Accepted Answer

$$V = I 	imes R$$

Question 12

During the absolute refractory period, why can't a neuron generate another action potential?

Accepted Answer

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

Question 13

Which of the following is a correct sequence of events during an action potential?

Accepted Answer

Depolarization → Repolarization → Hyperpolarization

Question 14

If the frequency of action potentials increases in a sensory neuron, what does this indicate about the stimulus?

Accepted Answer

The stimulus intensity is stronger.

Question 15

Which of the following best describes saltatory conduction?

Accepted Answer

Action potentials jump from one node of Ranvier to the next in myelinated axons.

Question 16

A neuron has a resting membrane potential of $$-70 mV. If $$the membrane potential changes to $$-80 mV$$, what has occurred?

Accepted Answer

Hyperpolarization

Question 17

Which of the following is NOT a function of the neuronal cell body (soma)?

Accepted Answer

Receiving incoming signals from other neurons

Question 18

Which of the following would most likely increase the speed of action potential propagation along an axon?

Accepted Answer

Increasing the amount of myelin

Question 19

Which statement about the propagation of an action potential is correct?

Accepted Answer

It is self-propagating and moves only in one direction due to refractory periods.

Question 20

A patient is exposed to a neurotoxin that blocks all $$\mathrm{K^+}$$ channels in neurons. What is the most immediate effect on the action potential?

Accepted Answer

The neuron will be unable to repolarize after the action potential spike.

Neurophysiology: Structure and Function of Neurons

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