Question

Which of the cranial nerves is mixed?
A. Optic
B. Olfactory
C. Vagus
D. Trochlear

Answer 1

Hint: Cranial nerves are the pairs of nerves which connects the brain with different parts of the body i.e. head, neck and trunk. There are 12 pairs of cranial nerves present in our body.

Complete Answer:
The 12 pairs of cranial nerves directly arise from the brain. The name of cranial nerves relate to their function. They are identified by roman numerals (I-XII). The nerves are of two types- Sensory nerves and motor nerves. Sensory nerves function for transmission of impulses related to touch, taste, see, hear, feel. Motor nerves help in transmission of impulses related to movement. Some nerves have both sensory and motor function called the mixed nerves.

 Optic and olfactory arise from the cerebrum. They function for seeing and smell. They come under sensory cranial nerves.
Vagus- It is both sensory and motor cranial nerve. It is responsible for regulation of the functions of the organs like lungs; digestive system and also controls certain reflex actions like sneezing and coughing.
Trochlear- It is a motor cranial nerve which regulates the activity of smooth oblique muscles.

The correct answer is (C), Vagus is a mixed cranial nerve.

Note: Vagus is mixed nerve because it contains both motor and sensory fibres. It has the widest distribution in the body as it stretches from neck and thorax to the abdomen. It is the longest cranial nerve.