Question 1

Which of the following best describes the role of the sodium-potassium pump ($$\mathrm{Na^+/K^+}$$ ATPase) in maintaining the resting membrane potential of a neuron?

Accepted Answer

It actively transports three $$\mathrm{Na^+}$$ ions out of the cell and two $$\mathrm{K^+}$$ ions in, helping maintain a negative charge inside the cell.

Question 2

A neuron is exposed to a toxin that selectively blocks voltage-gated $$\mathrm{K^+}$$ channels. What is the most likely effect on the action potential?

Accepted Answer

Repolarization will be delayed, causing a prolonged action potential.

Question 3

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

Accepted Answer

$$I = \dfrac{V}{R}$$

Question 4

During the absolute refractory period of a neuron, which of the following is true?

Accepted Answer

Voltage-gated $$\mathrm{Na^+}$$ channels are open or inactivated, preventing another action potential.

Question 5

Which type of neuron is most abundant in the human body and typically found in the central nervous system?

Accepted Answer

Multipolar neuron

Question 6

A patient presents with a loss of rapid reflexes in the limbs. Which type of nerve fiber is most likely affected?

Accepted Answer

Group A fibers: largest diameter, myelinated, fastest conduction

Question 7

Which of the following best explains why action potentials only travel in one direction along an axon?

Accepted Answer

Voltage-gated $$\mathrm{Na^+}$$ channels behind the action potential are inactivated during the refractory period.

Question 8

Which of the following scenarios would most likely result in hyperpolarization of a neuron?

Accepted Answer

Opening of $$\mathrm{K^+}$$ channels, allowing $$\mathrm{K^+} to $$exit the cell

Question 9

A graded potential differs from an action potential in which of the following ways?

Accepted Answer

Graded potentials decay with distance and can be depolarizing or hyperpolarizing.

Question 10

Which type of neural circuit is most likely involved in rhythmic activities such as breathing?

Accepted Answer

Reverberating circuit

Question 11

If the membrane potential of a neuron changes from $$-70\ \mathrm{mV} to$$ $$-55\ \mathrm{mV}$$, which process is occurring?

Accepted Answer

Depolarization

Question 12

Saltatory conduction is faster than continuous conduction because:

Accepted Answer

Myelin sheaths allow the electrical signal to jump between nodes of Ranvier.

Question 13

Which of the following best describes the function of a neuronal pool's discharge zone?

Accepted Answer

Neurons in this zone are more likely to generate an impulse due to proximity to the incoming fiber.

Question 14

A patient has a genetic mutation that causes excessive synaptic pruning during adolescence. Which condition might this predispose them to?

Accepted Answer

Schizophrenia

Question 15

Which of the following is true regarding the propagation of an action potential in a nonmyelinated axon?

Accepted Answer

Each successive segment of membrane depolarizes and repolarizes in sequence.

Question 16

Which of the following best explains how neurons encode stimulus intensity?

Accepted Answer

By increasing the frequency of action potentials.

Question 17

Which of the following is a correct statement about the permeability of the neuronal membrane at rest?

Accepted Answer

It is more permeable to $$\mathrm{K^+}$$ ions than to $$\mathrm{Na^+}$$ ions.

Question 18

Which of the following best describes a parallel after-discharge circuit?

Accepted Answer

A circuit where a single input stimulates neurons arranged in parallel arrays that converge on a single output cell, causing a burst of impulses.

Question 19

Which of the following is NOT a type of gated ion channel found in neuronal membranes?

Accepted Answer

Thermally gated channel

Question 20

Which neuron type is primarily responsible for transmitting sensory information from the skin to the central nervous system?

Accepted Answer

Unipolar (pseudounipolar) neuron

Nervous System – Part 2: Neuron Structure, Electrical Principles, and Signal Transmission

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