Question
Question: In a human being, the number of cranial nerves is A. 12 pairs B. 6 pairs C. 20 pairs D. 10 p...
In a human being, the number of cranial nerves is
A. 12 pairs
B. 6 pairs
C. 20 pairs
D. 10 pairs
Solution
Cranial nerves are the nerves that arise from the brain. They have nerves for every sense and some movement controlling nerves. They help in controlling both voluntary and involuntary movement. The first two paired nerves arise from the cerebrum and others emerge from the brain stem. They can be sensory or motor or both.
Complete answer: Cranial nerves help in transferring information from the brain to other parts of the body, mainly to the head and neck. These nerves are paired to control each side and present on both parts of the body. They are mainly responsible for bringing smell, vision, hearing, and movement of muscles. Cranial nerves are a part of the peripheral nervous system, although the sense of smell and sense of vision is considered to be part of the Central nervous system. Some of the cranial nerves are responsible for sensing and motor movement both and they contain only sensory fibres and motor fibres. Some are mixed nerves because they have both sensory and motor fibres.
There are twelve pairs of cranial nerves: The olfactory nerve, optic nerve, facial nerve, oculomotor nerve, vagus nerve, hypoglossal, nerve, vestibulocochlear nerve, accessory nerve, trochlear nerve, glossopharyngeal nerve, trigeminal nerve, and abducens nerve.
| Cranial nerves | Functions |
|---|---|
| Olfactory (I) | Sense of smell |
| Optic (II) | Sense of vision |
| Oculomotor (III) | Eye movement |
| Trochlear (IV) | Eye movement |
| Trigeminal (V) | Facial sensation |
| Abducens (VI) | Eye movement |
| Facial (VII) | Facial expression |
| Vestibulocochlear nerve (VIII) (auditory vestibular nerve) | Hearing and balance |
| Glossopharyngeal (XI) | Oral sensation and taste |
| Vagus (X) | Digestion, heart rate, respiratory rate, etc. |
| Accessory (XI) | Shoulder and head movement |
| Hypoglossal (XII) | Tongue movement |
Hence, the correct option is A.
Note: Spinal nerves and cranial nerves are different. Spinal nerves emerge from the spinal cord while cranial nerves emerge from the brain and brainstem. They control both voluntary and involuntary movements. They connect the brain to every cell of the body actually.