Question 1

Which neuroglial cell in the CNS is primarily responsible for forming the myelin sheath around axons, as shown in the first image?

Accepted Answer

Oligodendrocyte

Question 2

Refer to the action potential graph (second image). At which point does the steep phase of depolarization occur, and which ion is primarily responsible for this phase?

Accepted Answer

At the second dot; $$\mathrm{Na^+}$$ influx

Question 3

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

Accepted Answer

Create the blood-brain barrier and regulate the extracellular environment

Question 4

Which part of the neuron is the primary site for receiving synaptic input from other neurons?

Accepted Answer

Dendrites

Question 5

What is the approximate value of the resting membrane potential in a typical neuron?

Accepted Answer

$$-70\ \mathrm{mV}$$

Question 6

Which neuroglial cell is responsible for producing cerebrospinal fluid in the CNS?

Accepted Answer

Ependymal cell

Question 7

During which phase of the action potential (see second image) do potassium channels open, and what is the result?

Accepted Answer

During repolarization; $$\mathrm{K^+}$$ leaves the cell

Question 8

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

Accepted Answer

Myelin allows for saltatory conduction, where action potentials jump between nodes of Ranvier

Question 9

Which neurotransmitter is most directly associated with stimulating skeletal muscle contraction?

Accepted Answer

Acetylcholine

Question 10

A patient with multiple sclerosis experiences muscle weakness. Which of the following best explains this symptom?

Accepted Answer

Loss of oligodendrocytes leads to demyelination, slowing or blocking nerve impulse conduction

Question 11

Which of the following is a characteristic of the absolute refractory period during an action potential?

Accepted Answer

No action potential can be triggered, regardless of stimulus strength

Question 12

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

Accepted Answer

Engulf pathogens and remove debris

Question 13

Which of the following is true regarding the propagation of an action potential in a myelinated axon?

Accepted Answer

Depolarization occurs only at the nodes of Ranvier

Question 14

Which division of the nervous system is responsible for voluntary control of skeletal muscles?

Accepted Answer

Somatic nervous system

Question 15

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

Accepted Answer

All stimuli above threshold produce identical action potentials

Question 16

Which of the following is a function of the efferent division of the peripheral nervous system?

Accepted Answer

Carrying motor commands from the CNS to muscles and glands

Question 17

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

Accepted Answer

Gray matter contains neuron cell bodies; white matter contains myelinated axons

Question 18

Which of the following is true about graded potentials?

Accepted Answer

They decrease in magnitude as they spread from the site of stimulation

Question 19

Which type of summation occurs when multiple presynaptic neurons stimulate a postsynaptic neuron at the same time?

Accepted Answer

Spatial summation

Question 20

Which of the following best describes the role of gated sodium and potassium channels in the generation of an action potential?

Accepted Answer

They allow for rapid changes in membrane potential by opening and closing in response to voltage changes

Chapter 12

Study Guide - Practice Questions

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