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Lesson 6. The Cranial Nerves

2-6. THE CRANIAL NERVES

a.   Olfactory Nerve (I).

(1)  Sensory nerve.
(2)  Transmits smell impulses from receptors in the nasal mucosa to the brain.

b. Optic Nerve (II).

(1) Sensory nerve.
(2) Transmits visual impulses from the eye to the brain.

c. Oculomotor Nerve (III).

(1) Motor nerve.
(2) Contracts the eyeball muscles.

d. Trochlear Nerve (IV).

(1) Motor nerve.
(2) Contracts the eyeball muscles.

e. Trigeminal Nerve (V).

(1) Mixed nerve.
(2) Transmits pain, touch, and temperature impulses from the face and head to the brain (sensory function).
(3) Contracts the muscles of chewing (motor function).

f. Abducens Nerve (VI).

(1) Motor nerve.
(2) Contracts eyeball muscles.

g. Facial Nerve (VII).

(1) Mixed nerve.
(2) Transmits taste impulses from the tongue to the brain (sensory function).
(3) Contracts the muscles of facial expression and stimulates secretion of salivary and lacrimal glands (motor function).

h. Vestibulocochlear Nerve (VIII).

(1) Sensory nerve.
(2) Transmits hearing and balance impulses from the inner ear to the brain.

i. Glossopharyngeal Nerve (IX).

(1) Mixed nerve.
(2) Transmits taste impulses and general sensations from the tongue and pharynx (sensory function) to the brain.
(3) Contracts the swallowing muscles in the pharynx and stimulates secretions of the salivary glands.

j. Vagus Nerve (X).

(1) Mixed nerve.
(2) Transmits sensory impulses from the viscera (heart, smooth muscles, abdominal organs), pharynx, and larynx to the brain.
(3) Secrets digestive juices, contracts the swallowing muscles of the pharynx and larynx, slows down the heart rate, and modifies muscular contraction of smooth muscles.

k. Spinal Accessory Nerve (XI).

(1) Mixed nerve.
(2) Transmits sensory impulses from the pharynx and larynx to the brain.
(3) Contracts the muscles of the pharynx, larynx, and the neck.

l. Hypoglossal Nerve (XII).

(1) Motor nerve.
(2) Contracts the muscles of the tongue.

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