Question 1

Which of the following statements best describes the primary function of neuroglia (astrocytes) in the central nervous system?

Accepted Answer

They support, nurture, and protect neurons, and can form scar tissue after injury.

Question 2

Which structural classification of neurons is most commonly found in the human nervous system?

Accepted Answer

Multipolar

Question 3

A patient presents with progressive loss of sensation in both legs, followed by weakness in breathing. Which disease is most likely responsible, and what is its key feature?

Accepted Answer

Guillain-Barré syndrome; reversible demyelination in the PNS

Question 4

Which cell type is responsible for myelination in the peripheral nervous system (PNS)?

Accepted Answer

Schwann cells

Question 5

Why is axonal regeneration possible in the PNS but not in the CNS?

Accepted Answer

CNS axons lack neurolemma and are inhibited by glial signals, while PNS axons have neurolemma and supportive Schwann cells.

Question 6

Which of the following best explains why babies cannot walk at birth?

Accepted Answer

Myelination of motor neurons is incomplete and continues until about age 20.

Question 7

Which process is responsible for the rapid transport of organelles such as mitochondria along the axon, and what is the maximum speed?

Accepted Answer

Anterograde transport by kinesin at up to 400 mm/day

Question 8

Which disease is associated with the destruction of Schwann cells by bacterial toxins, potentially leading to fatal paralysis?

Accepted Answer

Diphtheria

Question 9

What is the main difference between myelination in the CNS and PNS?

Accepted Answer

CNS myelination involves oligodendrocytes with no neurolemma and no regeneration; PNS myelination involves Schwann cells with neurolemma and possible regeneration.

Question 10

Which of the following best describes the role of the node of Ranvier in nerve impulse conduction?

Accepted Answer

It allows saltatory conduction, increasing the speed of nerve impulses.

Question 11

A patient is bitten by a rabid animal. Which axonal transport mechanisms are involved in the progression of the rabies virus from the bite site to the CNS and then to the salivary glands?

Accepted Answer

Retrograde transport by dynein to CNS, anterograde by kinesin to salivary glands

Question 12

Which equation best represents the relationship between the speed of nerve impulse conduction and myelination?

Accepted Answer

$$v_{myelinated} \u003e v_{unmyelinated}$$

Question 13

Which type of neuron is primarily responsible for connecting sensory and motor pathways within the CNS?

Accepted Answer

Association (interneuron)

Question 14

Which of the following is a plausible consequence of heavy metal poisoning (e.g., lead or mercury) in the CNS?

Accepted Answer

Glial cell damage and demyelination, leading to neurological deficits

Question 15

Which of the following best describes the process of Wallerian degeneration in peripheral nerve repair?

Accepted Answer

Degeneration of the distal axon segment followed by regeneration from the proximal stump

Question 16

Which functional classification of neurons is responsible for transmitting impulses from receptors to the CNS?

Accepted Answer

Sensory (afferent) neurons

Question 17

Which of the following is true regarding the composition of myelin sheaths?

Accepted Answer

Myelin sheaths are composed of 80% lipid (e.g., sphingolipids) and 20% protein.

Question 18

Which neuroglial cell type is responsible for producing myelin in the CNS?

Accepted Answer

Oligodendrocytes

Question 19

Which of the following best explains the effect of multiple sclerosis on nerve conduction?

Accepted Answer

It destroys myelin sheaths, leading to scar tissue and impaired nerve conduction.

Neurons and Neuroglia: Structure, Function, and Clinical Relevance

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