Question

The number of purely motor pairs of cranial nerves in mammals is

• A. 3
• B. 5
• C. 4
• D. 2

Answer 1

Answer: (B)

5

The following cranial nerves are purely motor neurons, that is, they only carry the impulse to their respective effectors from the brain:

1. Cranial nerve-III or oculomotor which innervates the four eye muscles.
2. Cranial nerve-IV or trochlear which innervates the superior oblique eye muscle.
3. Cranial nerve-VI or abducens which innervates the lateral rectus eye muscle.
4. Cranial nerve-XI or accessory spinal which innervates muscles of pharynx and larynx.
5. Cranial nerve-XII or hypoglossal which innervates the muscles tongue.

Hence, the correct answer is '5'