Q: Which of the following equations correctly represents the movement of ions by the sodium-potassium pump?

$$3 \mathrm{Na}^+_{\text{in}} \rightarrow 3 \mathrm{Na}^+_{\text{out}}$$ and $$2 \mathrm{K}^+_{\text{out}} \rightarrow 2 \mathrm{K}^+_{\text{in}}$$

Question 1

Which of the following best describes the main function of astrocytes in the central nervous system (CNS)?

Accepted Answer

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

Question 2

A patient is diagnosed with multiple sclerosis (MS), which involves demyelination in the CNS. Which neuroglial cell is primarily affected in this disease?

Accepted Answer

Oligodendrocyte

Question 3

Which of the following is TRUE regarding the sodium-potassium pump in neurons?

Accepted Answer

It moves 3 Na+ ions out of the cell and 2 K+ ions into the cell per cycle.

Question 4

Which type of neuron is most commonly found in the central nervous system and is responsible for integrating sensory and motor information?

Accepted Answer

Multipolar neuron

Question 5

If a chemical stimulus opens sodium channels on a neuron's membrane, what is the immediate effect on the transmembrane potential?

Accepted Answer

The membrane depolarizes.

Question 6

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

Accepted Answer

The refractory period prevents reopening of voltage-gated Na+ channels immediately behind the action potential.

Question 7

A person accidentally touches a hot stove and quickly withdraws their hand. Which division of the nervous system is primarily responsible for this reflex action?

Accepted Answer

Somatic nervous system

Question 8

Which of the following would most likely occur if voltage-gated calcium channels at a cholinergic synapse were blocked?

Accepted Answer

Neurotransmitter release into the synaptic cleft would decrease.

Question 9

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 10

Which of the following equations correctly represents the movement of ions by the sodium-potassium pump?

Accepted Answer

$$3 \mathrm{Na}^+_{	ext{in}} ightarrow 3 \mathrm{Na}^+_{	ext{out}}$$ and $$2 \mathrm{K}^+_{	ext{out}} ightarrow 2 \mathrm{K}^+_{	ext{in}}$$

Question 11

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

Accepted Answer

Phagocytosing cellular debris and pathogens

Question 12

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

Accepted Answer

Dendrites or cell body

Question 13

Which of the following best describes the effect of an inhibitory postsynaptic potential (IPSP)?

Accepted Answer

It causes hyperpolarization of the postsynaptic membrane.

Question 14

Which of the following is TRUE about the all-or-none principle of action potentials?

Accepted Answer

If threshold is reached, an action potential of the same size is always produced.

Question 15

Which of the following best explains why myelinated axons conduct action potentials faster than unmyelinated axons?

Accepted Answer

Myelin allows action potentials to jump between nodes of Ranvier, reducing the number of times the membrane must depolarize.

Question 16

Which of the following would most likely be affected in a patient with Guillain-Barré syndrome?

Accepted Answer

Schwann cells in the PNS

Question 17

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

Accepted Answer

Depolarization to threshold → Opening of voltage-gated Na+ channels → Na+ influx → Repolarization by K+ efflux

Question 18

Which of the following best describes the role of interneurons?

Accepted Answer

They integrate sensory and motor information within the CNS.

Question 19

Which of the following is a characteristic of graded potentials but NOT action potentials?

Accepted Answer

They decrease in magnitude with distance from the stimulus.

Question 20

Which of the following best describes the effect of opening chemically gated K+ channels on the postsynaptic membrane?

Accepted Answer

It causes hyperpolarization and decreases the likelihood of an action potential.

Neural Tissue and the Nervous System: Structure, Function, and Physiology

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