Question 1

Which of the following best describes the role of afferent (sensory) neurons in the nervous system?

Accepted Answer

They send information towards the CNS from sensory receptors.

Question 2

Which glial cell type is responsible for myelinating axons in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes

Question 3

During an excitatory postsynaptic potential (EPSP), which ion movement is most likely to occur?

Accepted Answer

Na+ moves into the cell, causing depolarization.

Question 4

What is the primary function of the axon hillock in a neuron?

Accepted Answer

It is the site where action potentials are initiated if the threshold is reached.

Question 5

Which equation best represents the relationship between membrane potential ($$V_m$$), ion concentration, and permeability?

Accepted Answer

$$V_m = \frac{RT}{F} \ln \left( \frac{P_{K^+}[K^+]_{out} + P_{Na^+}[Na^+]_{out}}{P_{K^+}[K^+]_{in} + P_{Na^+}[Na^+]_{in}} \right)$$

Question 6

A patient with multiple sclerosis experiences muscle weakness and fatigue. Which of the following best explains the underlying neural mechanism?

Accepted Answer

Loss of myelin leads to decreased membrane resistance and current leak, slowing or blocking action potential propagation.

Question 7

Which of the following statements about graded potentials is correct?

Accepted Answer

Graded potentials decrease in strength as they move away from the initial point due to cytoplasmic and membrane resistance.

Question 8

What is the effect of opening Cl- channels in a postsynaptic neuron at rest?

Accepted Answer

The cell hyperpolarizes, leading to an IPSP.

Question 9

Which of the following best describes the 'all-or-none' nature of action potentials?

Accepted Answer

Action potentials only occur if the membrane potential reaches threshold, and all APs in a neuron have the same amplitude.

Question 10

Which phase of the action potential is associated with the closing of the Na+ inactivation gate and the opening of K+ channels?

Accepted Answer

Repolarization

Question 11

Why do action potentials only travel in one direction along the axon?

Accepted Answer

Because the refractory period prevents backward propagation of action potentials.

Question 12

Which of the following would most likely increase the conduction velocity of an action potential in a neuron?

Accepted Answer

Increasing axon diameter and adding myelin.

Question 13

A local anesthetic like lidocaine blocks pain by which mechanism?

Accepted Answer

Blocking voltage-gated Na+ channels, preventing action potential generation.

Question 14

During the relative refractory period, what is required to generate another action potential?

Accepted Answer

An extra large stimulus to reach threshold due to hyperpolarization.

Question 15

Which of the following best describes saltatory conduction?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing conduction speed.

Question 16

Which glial cell type is responsible for forming the blood-brain barrier in the CNS?

Accepted Answer

Astrocytes

Question 17

If a neuron’s resting membrane potential is $$-70\ \mathrm{mV}$$, what happens during depolarization?

Accepted Answer

The membrane potential becomes more positive than $$-70\ \mathrm{mV}.$$

Question 18

Which process is responsible for moving vesicles and organelles from the cell body to the axon terminal?

Accepted Answer

Axonal transport

Question 19

Which of the following is a function of microglia in the CNS?

Accepted Answer

Acting as immune cells and scavengers

Question 20

Which of the following best explains why graded potentials decrease in strength as they travel?

Accepted Answer

Because of cytoplasmic resistance and current leak due to membrane resistance.

Neural Physiology: Organization, Cell Function, and Neural Signaling

Study Guide - Practice Questions