The Cranial Nerves



Cranial nerves are pairs of nerves that connect the brain to different parts of the head, neck, and trunk. There are 12 of them, each named for their function or structure and numbered in Roman numbers.

Cranial nerve I: The olfactory nerve

 This is for the sense of smell, it is one of the few nerves that are capable of regeneration.

Cranial nerve II: The optic nerve

This nerve carries visual information from the retina of the eye to the brain.

Cranial nerve III: The oculomotor nerve

This controls most of the eye’s movements, the constriction of the pupil, and maintains an open eyelid.

Cranial nerve IV: The trochlear nerve

A motor nerve that innervates the superior oblique muscle of the eye, which controls rotational movement.

Cranial nerve V: The trigeminal nerve

This is responsible for sensation and motor function in the face and mouth.

Cranial nerve VI: The abducens nerve  

A motor nerve that innervates the lateral rectus muscle of the eye, which controls lateral movement.

Cranial nerve VII: The facial nerve

This controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity.

Cranial nerve VIII: The vestibulocochlear nerve

This is responsible for transmitting sound and equilibrium (balance) information from the inner ear to the brain.

Cranial nerve IX: The glossopharyngeal nerve

This nerve receives sensory information from the tonsils, the pharynx, the middle ear, and the rest of the tongue.

Cranial nerve X: The vagus nerve

This is responsible for many tasks, including heart rate, gastrointestinal peristalsis, sweating, and muscle movements in the mouth, including speech and keeping the larynx open for breathing.

Cranial nerve XI: The spinal accessory

This nerve controls the specific muscles of the shoulder and neck.

Cranial nerve XII: The hypoglossal nerve

This nerve controls the tongue movements of speech, food manipulation, and swallowing.


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