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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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