The following is true about the vestibular system:

Correct Answer: D

Rationale: Vestibular system affects balance, not muscle tone directly (A). Semicircular canals detect angular acceleration (not linear, B), utricle detects linear (not rotational, C). Damage causes vertigo (D, correct). D is true.

Correct Answer: A

Rationale: The dura mater (A) forms and supports venous sinuses (e.g., superior sagittal) for CNS blood drainage. The arachnoid mater (B) and subarachnoid space (C) handle CSF, and pia mater (D) adheres to the brain. A is correct.

Correct Answer: A

Rationale: The peripheral nervous system (PNS) controls peripheral structures. The trigeminal ganglion (A) is a sensory relay, not directly controlled by PNS motor output. Gastric plexus (B), sympathetic chain (C), and cervical plexus (D) are PNS autonomic/somatic effectors. A is the least directly controlled.

Correct Answer: B

Rationale: The soma, or cell body, of a neuron contains the nucleus, which houses the cell’s genetic material. Dendrites receive signals, axons transmit them, and the synaptic end bulb releases neurotransmitters, but only the soma contains the nucleus.

Correct Answer: B

Rationale: Upper motor neurons (UMNs) in the CNS target lower motor neurons (LMNs) in the spinal cord or brainstem, which then innervate skeletal muscles. UMNs don’t directly target muscles or other brain regions like the cortex or thalamus.