PREVIOUSLY ASKED IN:
WBPSC Miscellaneous Preliminary 2023
Answer
12 pairs
Explanation
Cranial nerves are the nerves that emerge directly from the brain. In humans, there are exactly 12 pairs of cranial nerves. They are responsible for conveying sensory information and controlling muscles in the head, neck, and facial regions. In contrast, there are 31 pairs of spinal nerves that emerge from the spinal cord.
Key Points
- > Cranial Nerves = 12 pairs.
- > Spinal Nerves = 31 pairs.
- > Vagus nerve (X) is the longest cranial nerve.
- > Trigeminal nerve (V) is the largest cranial nerve.
- > Olfactory nerve (I) is responsible for the sense of smell.
- > Optic nerve (II) is responsible for vision.
- > Cranial nerves can be sensory, motor, or mixed.
Additional Information
Human Nervous System
| Nerve Type | Number | Origin | Longest/Largest |
|---|---|---|---|
| Cranial Nerves | 12 pairs | Brain | Vagus (Longest) |
| Spinal Nerves | 31 pairs | Spinal Cord | Sciatic Nerve |
Memory Tips
- Remember the ratio 12 : 31. Brain has 12 months (pairs), Spine has 31 days (pairs).