True about corticospinal tract:

Correct Answer: D

Rationale: control voluntary movement. The corticospinal tract originatfrom the primary motor cortex (precentral gyrus, not just premotor, making B incomplete), decussatin the medullary pyramids (not midbrain, making A wrong), and terminatin the ventral horn (not posterior, making C incorrect). Its primary function is to control voluntary movements, particularly fine motor skills (e.g., hand movements), via upper motor neurons synapsing on lower motor neurons. Damage, like in stroke, impairs voluntary actions contralaterally. Thus, D accurately reflects the corticospinal tracts role, making it the correct answer.

Correct Answer: D

Rationale: control voluntary movement . The corticospinal tract originatfrom the motor cortex (not cerebellum, making B wrong), decussatin the medullary pyramids (not pons, making A incorrect), and terminatin the ventral horn (not posterior, making C false). It controls voluntary movements, like fine motor skills, via upper motor neurons to spinal motor neurons. This role is critical, as seen in paralysis post-lesion. Thus, D is the true statement.

Correct Answer: C

Rationale: Control voluntary movement of the muscle of the face only , which is false. The corticonuclear tract originatfrom the precentral gyrus (A is true), descends through the internal capsule, and terminatin brainstem cranial nerve nuclei (B is true), such as 5 (jaw), 7 (face), 10 (pharynx), and 12 (tongue). It controls voluntary movements not just of the face, but also head and neck muscl(e.g., tongue, larynx), making C inaccurate. Fibers decussate partially in the brainstem (D is true), with variations e.g., lower facial fibers cross, but upper facial innervation is bilateral. This broader role is evident in deficits like contralateral tongue deviation or dysphagia from lesions, not face-only effects. Thus, C is the exception, as it wrongly limits the tracts function, making it the correct answer.

Correct Answer: C

Rationale: Controls only the musclof the face , which is false. The corticonuclear tract originatfrom the precentral gyrus of the frontal lobe (A is true), descends through the internal capsule, and terminatin brainstem cranial nerve nuclei (B is true), such as 5 (jaw), 7 (face), 10 (pharynx), and 12 (tongue). It donot control only facial muscl(C is incorrect); it also governs voluntary movements of the head (e.g., tongue deviation) and neck (e.g., shrugging shoulders via cranial nerve 11), making its scope broader. Choice D is true; it decussatpartially, with variations e.g., lower facial fibers cross, but upper face innervation is bilateral. This is evident in stroke patients with contralateral tongue weakness or dysphagia, not just facial deficits. Thus, C is the exception due to its inaccurate limitation, making it the correct answer.

Correct Answer: D

Rationale: It receivinput from stretch receptors in the stomach wall . The vomiting reflex is involuntary (A is false), triggered by medullary signals, not cortical control, unlike swallowings voluntary start. The vomiting center is in the medulla oblongata (not hypothalamus, making B wrong), near the area postrema. Choice C is false; cranial nerve 8 (vestibulocochlear) is involved, relaying vestibular input (e.g., motion sickness). Choice D is true; stretch receptors in the stomach wall signal via the vagus nerve (cranial nerve 10) to the vomiting center, as in overdistension-induced vomiting. This medullary integration is evident in emetic responsto gastric irritation, supporting Ds accuracy. Thus, D is the true statement.