Question 1

Which of the following best describes the main function of the sodium-potassium exchange pump in neurons?

Accepted Answer

It uses ATP to move 3 sodium ions out of the cell and 2 potassium ions into the cell, maintaining the resting membrane potential.

Question 2

A patient suffers a spinal cord injury that disrupts the myelin sheath in the CNS. Which neuroglial cell type is most likely affected, and what is a direct consequence?

Accepted Answer

Oligodendrocytes; decreased speed of action potential propagation

Question 3

Which of the following scenarios best illustrates the 'all-or-none' principle of action potentials?

Accepted Answer

A neuron fires an action potential only if the membrane potential reaches threshold, and the action potential is always the same size.

Question 4

Which of the following best explains why the resting membrane potential of a neuron is closer to $$-90\ \mathrm{mV} ($$the equilibrium potential for potassium) than to $$+66\ \mathrm{mV} ($$the equilibrium potential for sodium)?

Accepted Answer

There are more potassium leak channels than sodium leak channels, making the membrane more permeable to potassium.

Question 5

A patient is prescribed a drug that blocks voltage-gated sodium channels. What is the most immediate effect on neuronal signaling?

Accepted Answer

Action potentials cannot be initiated, preventing nerve impulse transmission.

Question 6

Which of the following is TRUE regarding the propagation of action potentials in myelinated versus unmyelinated axons?

Accepted Answer

Saltatory propagation allows the action potential to 'jump' from node to node, increasing speed and energy efficiency.

Question 7

A neuron receives multiple excitatory postsynaptic potentials (EPSPs) at different locations on its dendrites at the same time. This is an example of:

Accepted Answer

Spatial summation

Question 8

Which of the following best describes the role of astrocytes in the central nervous system?

Accepted Answer

They maintain the blood-brain barrier and regulate the interstitial environment.

Question 9

Which neurotransmitter is most directly associated with the 'runner's high' and pain relief, and what is its classification?

Accepted Answer

Endorphin; neuropeptide (opioid)

Question 10

A patient is experiencing muscle weakness due to demyelination in the peripheral nervous system. Which cell type is most likely affected?

Accepted Answer

Schwann cells

Question 11

Which of the following best explains why Type A fibers conduct action potentials faster than Type C fibers?

Accepted Answer

Type A fibers are myelinated and have a large diameter, reducing resistance to ion flow.

Question 12

Which of the following is a correct sequence of events at a chemical synapse?

Accepted Answer

Action potential arrives at axon terminal → voltage-gated calcium channels open → neurotransmitter is released into synaptic cleft

Question 13

Which of the following statements about graded potentials is TRUE?

Accepted Answer

They are localized changes in membrane potential that decrease in strength with distance from the stimulus.

Question 14

A neuron is exposed to a drug that increases the number of open potassium channels at rest. What is the most likely effect on the neuron's membrane potential?

Accepted Answer

The membrane potential will become more negative (hyperpolarize).

Question 15

Which of the following best describes the difference between white matter and gray matter in the CNS?

Accepted Answer

White matter contains many myelinated axons; gray matter contains neuron cell bodies, unmyelinated axons, and dendrites.

Question 16

Which of the following is a function of the enteric nervous system?

Accepted Answer

It independently regulates digestive functions, but can be influenced by the CNS.

Question 17

A neuron receives both EPSPs and IPSPs simultaneously. What determines whether an action potential will be generated?

Accepted Answer

The net effect of all EPSPs and IPSPs at the axon hillock reaching threshold.

Question 18

Which of the following is TRUE about the absolute refractory period?

Accepted Answer

No action potential can be generated, regardless of stimulus strength, because voltage-gated sodium channels are already open or inactivated.

Question 19

Which of the following neurotransmitters is classified as a biogenic amine and is associated with mood regulation and the digestive system?

Accepted Answer

Serotonin

Question 20

Which of the following best describes the effect of an inhibitory neurotransmitter on the postsynaptic membrane?

Accepted Answer

It causes hyperpolarization, making the neuron less likely to reach threshold.

Chapter 12: Nervous Tissue and the Nervous System – Mini-Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards