The localization of sensation is a function of:

Correct Answer: B

Rationale: The primary sensory cortex (B) localizes sensation via somatotopic mapping. Stimulus (A) and receptors (C) initiate it, and medullary centers (D) relay, but localization is cortical. B is correct.

Correct Answer: A

Rationale: The diencephalon develops into the thalamus, hypothalamus, and parts of the retina (A). Midbrain (B) arises from the mesencephalon, pons and cerebellum (C) from the rhombencephalon (metencephalon), and cerebrum (D) from the telencephalon. A is correct.

Correct Answer: C

Rationale: The internal carotid artery (C) enters the cranium via the carotid canal, supplying the brain. The common carotid (A) branches into it but doesn’t enter, jugular vein (B) drains blood, and aorta (D) is systemic. C is correct.

Correct Answer: A

Rationale: A fascicle (A) is a bundle of axons within a peripheral nerve. Tracts (B) are CNS axon bundles, nerve roots (C) are spinal nerve origins, and epineurium (D) is the nerve’s outer layer. A is correct.

Correct Answer: A

Rationale: Oligodendrocytes provide myelin for axons in the central nervous system (CNS), where tracts are located. Schwann cells myelinate axons in the peripheral nervous system (PNS), astrocytes support neurons, and satellite cells support cell bodies in the PNS.