craninal nerves

Cranial Nerves

There are 12 pairs of cranial nerves (

VI. The abducens nerve

another nerve sending controlling impulses to an eyeball muscle.

VII. The facial nerve

is largely motor. The muscles of facial expression are all supplied by branches from the facial nerve. This nerve also includes special sensory fibers for taste and it contains secretory fibers to the smaller salivary glands (the submandibular and sublingual) and to the lacrimal (tear) gland.

X. The vagus nerve

is the longest cranial nerve. It supplies most of the organs in the thoracic and abdominal cavities. This nerve also contains motor fibers supplying the larynx (voice box) and pharynx and also glands that produce digestive juices and other secretions.

IV. The trochlear nerve

supplies one eye-ball muscle.

V. The trigeminal nerve

the great sensory nerve of the face and head. It has three branches that transport general sense impulses (e.g., pain, touch, temperature) from the eye, the upper jaw, and the lower jaw. Motor fibers to the muscles of mastication (chewing) join the third branch.

four categories of cranial nervers

Special sensory impulses; General sensory impulses, Somatic motor impulses, Visceral motor impulses

They are numbered, usually in Roman numerals, according to their connection with the brain,

Except for the first two pairs, which connect with the cerebrum and diencephalon, respectively, all the cranial nerves connect with the brain stem. A

XII. The hypoglossal nerve,

carries impulses controlling the tongue muscles.

VIII. The vestibulocochlear nerve

carries sensory impulses for hearing and equilibrium from the inner ear. This nerve was formerly called the auditory or acoustic nerve.

I. The olfactory nerve

carries smell impulses from receptors in the nasal mucosa to the brain.

II. The optic nerve

carries visual impulses from the eye to the brain.

III, IV, VI, XI, and XII

contain all or mostly motor fibers.

V, VII, IX, and X)

contain both sensory and motor fibers;

(I, II, and VIII)

contain only sensory fibers;

IX. The glossopharyngeal nerve

contains general sensory fibers from the posterior tongue and the pharynx (throat). This nerve also contains sensory fibers for taste from the posterior third of the tongue, secretory fibers that supply the largest salivary gland (parotid), and motor nerve fibers to control the swallowing muscles in the pharynx.

XI. The accessory nerve aka the spinal accessory nerve

is a motor nerve with two branches. One branch controls two muscles of the neck, the trapezius and sternocleidomastoid; the other supplies muscles of the larynx.

III. The oculomotor nerve

is concerned with the contrac-tion of most of the eye muscles.