Question 1

Which of the following best describes the function of the myelin sheath in the central nervous system (CNS)?

Accepted Answer

It increases the speed of nerve impulse transmission by electrically insulating axons.

Question 2

A patient with multiple sclerosis experiences slowed nerve conduction. Which cellular structure is most likely damaged?

Accepted Answer

Myelin sheath

Question 3

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

Accepted Answer

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

Question 4

During the generation of an action potential, which phase is characterized by an increased permeability to sodium ions ($Na^+$)?

Accepted Answer

Depolarization

Question 5

Which type of neuron is typically involved in sensing the smell of perfume?

Accepted Answer

Bipolar sensory neuron

Question 6

What is the main difference between graded potentials and action potentials?

Accepted Answer

Graded potentials decay with distance, while action potentials do not.

Question 7

A neuron receives two stimuli in rapid succession. Only one action potential is generated. What is the most likely explanation?

Accepted Answer

The second stimulus occurred during the absolute refractory period.

Question 8

Which of the following best explains why action potentials do not decrease in size as they propagate along an axon?

Accepted Answer

Action potentials are regenerated at each patch of membrane.

Question 9

Which of the following nerve fibers conducts impulses the fastest?

Accepted Answer

Group A fibers

Question 10

If the resting membrane potential of a neuron is $-70\ \mathrm{mV}$, what does the negative sign indicate?

Accepted Answer

The cytoplasmic side of the membrane is negatively charged relative to the outside.

Question 11

Which of the following changes would most likely result in depolarization of a neuron?

Accepted Answer

An increase in membrane permeability to $Na^+$

Question 12

Which of the following best describes the electrochemical gradient?

Accepted Answer

It is the sum of the concentration gradient and the electrical gradient for an ion.

Question 13

A graded potential is most likely to occur in which part of a neuron?

Accepted Answer

Dendrites or cell body

Question 14

Which of the following is true regarding the absolute refractory period?

Accepted Answer

No action potential can be generated, regardless of stimulus strength.

Question 15

Which process allows action potentials to 'jump' from one node of Ranvier to the next in myelinated axons?

Accepted Answer

Saltatory conduction

Question 16

Which of the following would most likely increase the conduction velocity of a nerve fiber?

Accepted Answer

Increasing myelination

Question 17

Which of the following best describes a postsynaptic potential?

Accepted Answer

A graded potential produced by neurotransmitter release at a synapse

Question 18

A nerve fiber is defined as which part of the neuron?

Accepted Answer

Axon

Question 19

Which of the following best explains how neurons code for stimulus intensity?

Accepted Answer

By increasing the frequency of action potentials

Question 20

Which of the following is a correct statement about the resting membrane potential?

Accepted Answer

It is maintained by differences in ion concentration and membrane permeability.

Neurons and Electrical Signaling in the Nervous System

Study Guide - Practice Questions