The terminal portion of the spinal cord is known as the:

Correct Answer: B

Rationale: The conus medullaris is the tapered, terminal end of the spinal cord (around L1-L2). The cauda equina is nerve roots below it, and the filum terminale is a fibrous extension.

Correct Answer: D

Rationale: Individual nerve fibers (axons) are covered by endoneurium, not listed here. Perineurium (A) surrounds fascicles, epineurium (C) encases the entire nerve, and pericardium (B) is unrelated (heart tissue). Thus, 'none of the above' (D) is correct.

Correct Answer: D

Rationale: Pain receptors (nociceptors) are slowly adapting (not rapidly, ruling out A), pressure receptors (e.g., Pacinian corpuscles) are rapidly adapting (not slowly, ruling out B), and touch receptors (e.g., Meissner’s) are rapidly adapting (not non-adaptive, ruling out C). Receptors can indeed be stimulated by chemical changes (D), as seen in chemoreceptors and nociceptors.

Correct Answer: B

Rationale: Pain is transmitted via the lateral spinothalamic tract (B), not posterior columns (A, which carry vibration/position), nor the 9th cranial nerve (C, glossopharyngeal, mainly taste/pharynx). Perception involves the cortex, but not 'only' there (D). B is correct.

Correct Answer: C

Rationale: Bitemporal hemianopia results from optic chiasm compression, commonly by pituitary tumors (C). Optic nerve lesions (A) cause unilateral loss, optic tract (B) causes homonymous hemianopia, and occipital lesions (D) affect cortical vision. C is correct.