Question

Describe three kinds of nerves, giving the example of each.

Answer 1

A nerve is formed by a group of nerve fibres (axons) enclosed by the tubular medullary sheath. The medullary sheath acts as insulation and does not allow mixing up of impulses of the neighbouring axons (nerve fibres) We have three kinds of nerves:

1. Sensory nerve:  It brings impulses from sense organs, as these have sensory fibres. These nerves carry the impulses from the sense organs to the brain or to the spinal cord as the optic nerve of the eye.
   Example: The optic nerve is a sensory nerve that transmits visual information from the eyes to the brain.
2. Motor nerves: These carry impulses to muscles or glands from the brain or spinal cord. These nerves have only motor fibres as nerves to the muscles of the eyeball.
   Example: The sciatic nerve is a motor nerve that controls the muscles in the back of the leg and lower limb.
3. Mixed nerve: It has both sensory and motor fibres as nerve going to the tongue.
   Example: The spinal nerves are mixed nerves that carry sensory information to the central nervous system and motor commands to the muscles.