Definition
Definition
Nerves attached to the brain.
Symptoms
physiology
The word encephalon comes from en, inside, and képhalê, which means head. It is the part of the nervous system contained within the cranium and comprising the cerebrum, the cerebellum, and the brainstem (upper segment of the spinal cord). This organ controls the entire body. There are twelve pairs of cranial nerves (one on each side). They are numbered from I to XII:
I: olfactory nerve (of smell)
II: optic nerve (of sight)
III, IV, VI: motor nerves of the eyes (controlling eye movements)
V: trigeminal nerve (allowing control of jaw movements: chewing and facial sensitivity)
VII: facial nerve (allowing control of facial muscle movements and the secretion of saliva and tears, sensitivity of the ear and that of part of the tongue)
VIII: auditory nerve (hearing and balance)
IX: glossopharyngeal nerve (controls the movements of the pharynx, its sensitivity, another part of the tongue, the secretion of saliva)
X: pneumogastric nerve also called vagus nerve (controls the movements of the soft palate, heart and blood vessels, larynx, lungs, digestive tract)
XI: Spinal nerve (controls movement of the neck and shoulder muscles)
XII: Hypoglossal nerve (controls tongue movements in general) The nerve fibers (nerve threads) constituting the spinal nerves themselves originate in small islands of gray matter scattered throughout the white matter of the brain.
