Question

Which cranial nerves are sensory?
A. 1, 2, 8
B. 3, 4, 6, 11, 12
C. 5, 7, 9, 10
D. None of the above

Answer 1

Hint:- Cranial nerves are a set of nerves that help in connecting the brain to various parts of the head, neck, and trunk. They are twelve in number each having a particular name according to the function they perform.

Complete answer:
Each cranial nerve can be represented in Roman numerals starting from I to XII. The numbering given is based upon their location starting from the front of the head to the back. Their functions are usually sensory or motor. Sensory nerves are concerned with the function of sense, such as touch, hear, and smell. Motor nerves are responsible for controlling the movement of muscles and glands as well as to check their functions. The cranial nerve I (CN I) is the olfactory nerve and is concerned with the smell. CN II also contains sensory neurons and is concerned with the regulation of vision. CN VIII controls the hearing and equilibrium senses and is also known as the vestibulocochlear nerve. Thus, Cranial nerves I, II, and VIII serve the function of sensing and are called pure sensory nerves.
So, the correct option is (A) 1, 2, 8.

Additional information:- Cranial nerves III, IV, VI, XI, and XII functions as motor nerves. CN III and IV function as motor nerves for the various muscles of the eyes. CN VI functions on the rectus muscle of the eyes. CN XI provides the motor functioning to the trapezius and sternocleidomastoid muscles. CN XII is a motor nerve for muscles of the tongue.
Remaining cranial nerves, i.e. V, VII, IX, and X, are mixed sensory and motor nerves performing both the functions.

Note:- Olfactory nerve sends sensory signals to the brain about the smell that we encounter through nerve impulses, and the brain recognizes the smell from previous encounters. Similar steps are followed for the other sensory nerves as well.