Tuesday, July 26, 2011

Cranial Nerves

The cranial nerves are the twelve pairs of nerves which arise straight from the brain. The first and second cranial nerves (the olfactory and optic nerves) emerge from the cerebrum; the other ten pairs come off the brainstem. They can be observed on the bottom surface of the brain; they are:

I Olfactory nerve: a sensory pair that transmit the sense of smell.
II Optic nerve: sensory; transmits visual information from the eye to the occipital lobe of the brain.
III Oculomotor nerve: motor; innervates the eye muscles (eye movement and pupil constriction).
IV Trochlear nerve: motor; innervates the superior oblique muscle of the eye.
V Trigeminal nerve: sensory and motor; receives sensation from the face and innervates the muscles of mastication.
VI Abducens nerve: motor; innervates the lateral rectus muscle of the eye.
VII Facial nerve: sensory and motor; taste, somatosensory information from ear and innervates muscles used in facial expression.
VIII Vestibulocochlear nerve: sensory; hearing and balance.
IX Glossopharyngeal nerve: sensory and motor; somatosensory information from tongue, tonsil, pharynx; controls some muscles used in swallowing.
X Vagus nerve: sensory and motor; autonomic functions of viscera (glands, digestion, heart rate).
XI Accessory nerve: motor; controls sternocleidomastoid and trapezius muscles.
XII Hypoglossal nerve: motor; provides motor innervation to the muscles of the tongue.

Cranial Nerves (Video)