Question

Which of the following pairs of cranial nerves is/are of a mixed category?
(A) Glossopharyngeal and hypoglossal
(B) Glossopharyngeal and vagus
(C) Trigeminal and facial
(D) Both B and C

Answer 1

Hint: Cranial nerves arise from the brain and it occurs in 12 pairs. Cranial nerves containing both sensory fibres and motor fibres are called mixed nerves which are 4 in pairs. Mixed nerves mainly present on the surface of mucus containing internal organs.

Complete answer:
Peripheral nerves consist of cranial nerves which arise from the brain and spinal nerves which arise from the spinal cord. A total of 12 pairs of cranial nerves are present from which 10 are obtained from the brain stem and all 12 pairs of cranial nerves pass through the skull foramina. Out of the 12 pairs of nerves, four pairs are of a mixed type like trigeminal, facial, glossopharyngeal and vagus which consists of both motor nerve fibre and sensory nerve fibre.

Additional information:
-The trigeminal nerve is the fifth cranial nerve present on the ventral side of pons responsible for sensation in the face.
-The facial nerve is the seventh cranial nerve emerging out from the pons of the brain stem. It controls facial expression, saliva secretion, neck movement, etc.
-Glossopharyngeal is the ninth cranial nerve which lies on the side of the medulla and controls taste bud, pharyngeal contraction, saliva secretion etc.
-Vagus is the tenth cranial nerve lying on the side of the medulla and controls heart, lungs and stomach sensation and movement.

So, the correct answer is 'Both B and C'.

Note:
The trigeminal nerve is divided into ophthalmic, maxillary and mandibular. The ophthalmic and maxillary nerve is sensory which is present in the skin of nose, eyelids, forehead and on the mucous membrane of cheeks, upper lips and lower eyelids. The mandibular is the mixed type which presents on the lower jaw, lower lip, pinna and tongue.