Which part of the brain has a blood-brain barrier?

Correct Answer: A

Rationale: The blood-brain barrier (BBB) is a protective feature of the CNS, but the anterior pituitary lacks a complete BBB, allowing hormone exchange with the bloodstream. The posterior pituitary, pineal body, and area postrema have weaker or no BBB to facilitate their functions (e.g., hormone secretion or vomiting trigger).

Correct Answer: B

Rationale: The anterior spinal artery (singular) arises from the vertebral arteries, supplying the anterior spinal cord. There are two posterior spinal arteries, typically from the posterior inferior cerebellar arteries, not superior cerebellar.

Correct Answer: C

Rationale: The trochlear nerve (CN IV) innervates only the superior oblique. The trigeminal (V) has motor and sensory roles, abducens (VI) exits via the superior orbital fissure, and hypoglossal (XII) exits via the hypoglossal canal.

Correct Answer: B

Rationale: The vagus nerve (CN X) arises from the medulla, with nucleus ambiguus fibers (shared with CN XI origins) for pharyngeal/laryngeal muscles. It doesn’t supply the diaphragm (phrenic nerve) or face.

Correct Answer: D

Rationale: The auriculotemporal nerve is a mandibular (V3) branch, supplying the scalp and TMJ. Infraorbital (V2), external nasal (V1), and zygomaticofacial (V2) are not V3.