Question 1

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

Accepted Answer

They maintain the blood-brain barrier, regulate the interstitial environment, and guide neuron development.

Question 2

A patient presents with muscle weakness and loss of coordination. MRI reveals demyelination in the CNS. Which disease is most likely responsible for these symptoms?

Accepted Answer

Multiple sclerosis (MS)

Question 3

Which equation correctly represents the action of the sodium-potassium exchange pump in maintaining the resting membrane potential?

Accepted Answer

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

Question 4

Which type of neuron is most commonly found in sensory pathways of the peripheral nervous system (PNS)?

Accepted Answer

Unipolar (pseudounipolar) neuron

Question 5

A graded potential that causes the membrane potential to become more negative than the resting potential is called:

Accepted Answer

Hyperpolarization

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 the membrane behind the action potential from being re-excited.

Question 7

Which of the following neurotransmitters is most associated with the regulation of mood and is targeted by SSRI antidepressants?

Accepted Answer

Serotonin

Question 8

A patient is exposed to strychnine, which blocks glycine receptors. What is the most likely effect on the nervous system?

Accepted Answer

Uncontrolled muscle contractions due to loss of inhibition

Question 9

Which of the following best describes saltatory propagation of an action potential?

Accepted Answer

The action potential jumps from one node of Ranvier to the next, increasing speed and efficiency.

Question 10

Which type of axon would transmit a pain signal from the skin to the CNS most slowly?

Accepted Answer

Type C fiber

Question 11

Which of the following is TRUE regarding graded potentials?

Accepted Answer

They diminish in strength as they spread from the site of stimulation.

Question 12

Which of the following best describes the function of microglia in the CNS?

Accepted Answer

They act as immune cells, removing debris and pathogens by phagocytosis.

Question 13

Which of the following events occurs first during the generation of an action potential?

Accepted Answer

Depolarization to threshold

Question 14

A neuron receives simultaneous excitatory and inhibitory inputs at different synapses. What process determines whether an action potential will be generated?

Accepted Answer

Spatial summation

Question 15

Which of the following is a direct (ionotropic) effect of a neurotransmitter?

Accepted Answer

Opening of chemically gated ion channels resulting in immediate changes in membrane potential

Question 16

Which of the following best explains why the resting membrane potential is negative?

Accepted Answer

Potassium ions leak out of the cell more than sodium ions leak in, and negatively charged proteins remain inside.

Question 17

Which of the following is NOT a function of Schwann cells in the peripheral nervous system?

Accepted Answer

Producing scar tissue that inhibits axon regrowth

Question 18

Which of the following best describes the effect of acetylcholine (ACh) at the neuromuscular junction?

Accepted Answer

It opens chemically gated sodium channels, leading to depolarization and possible action potential generation.

Question 19

Which of the following is TRUE regarding the absolute refractory period of an action potential?

Accepted Answer

No stimulus, regardless of strength, can trigger another action potential.

Nervous Tissue: Structure, Function, and Physiology

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