The nurse is explaining the pathophysiology of multiple sclerosis to a client just diagnosed with this condition. As part of this explanation, the nurse teaches the client that the function of the myelin sheath is to:

Correct Answer: C

Rationale: Myelin insulates axons, enabling rapid, smooth impulse transmission via saltatory conduction. It doesn’t nourish cells, connect brain to periphery, or protect dendrites specifically.

Correct Answer: B

Rationale: The triceps reflex is a somatic reflex (skeletal muscle response) via spinal cord (C6-C7), not autonomic, cranial nerve, or brainstem-mediated.

Correct Answer: B

Rationale: The cerebrum does comprise ~80% of brain mass, has a convoluted gray matter cortex, and is the telencephalon. However, it has four lobes per hemisphere (frontal, parietal, temporal, occipital), not 'four paired lobes' as a distinct entity, making B false.

Correct Answer: B

Rationale: Parkinson’s disease results from basal ganglia dysfunction (e.g., dopamine loss in substantia nigra), affecting motor control. The pons, parietal lobe, and thalamus have other roles; 'corpus striatum' is part of basal ganglia but less specific.

Correct Answer: B

Rationale: The corpus callosum connects cerebral hemispheres and has no autonomic role like blood pressure regulation. Pons and medulla regulate respiration, thalamus relays pain, and hypothalamus controls temperature.