Questions: Question 25 Which of the following is true of cranial nerves? (A) All have motor functions (B) Some have sensory-only functions (C) All have sensory functions (D) Most have direct influence on visceral homeostasis

The answer is (B): Some have sensory-only functions.

Explanation for each option:

(A) All have motor functions - This is incorrect. Not all cranial nerves have motor functions. Some cranial nerves are purely sensory, such as the olfactory nerve (I) and the optic nerve (II).

(B) Some have sensory-only functions - This is correct. Certain cranial nerves, like the olfactory nerve (I) and the optic nerve (II), are purely sensory and do not have motor functions.

(C) All have sensory functions - This is incorrect. While many cranial nerves have sensory components, not all of them do. For example, the accessory nerve (XI) is primarily motor.

(D) Most have direct influence on visceral homeostasis - This is incorrect. While some cranial nerves, such as the vagus nerve (X), play a significant role in visceral homeostasis, it is not true for most cranial nerves. Many cranial nerves are involved in sensory and motor functions related to the head and neck.

Summary: The correct answer is (B): Some have sensory-only functions. This accurately reflects the nature of certain cranial nerves that are purely sensory.