Anatomy and Cell Biology 3319 Chapter 13: reading 13 cranial nerves (431-439)
24 Jan 2019
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Department
Professor
CRANIAL NERVES
cranial nerves: attach to the brain and pass through various foramina in the skull
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nerves are numbered I to XII in rostral to caudal direction
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first 2 pairs attach to forebrain, the rest to the brain stem
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vagus nerve (X) extends to the abdomen but all others innervate only head and
neck
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olfactory: sensory nerves of smell
I.
optic: develops as an outgrowth of the brain, sensory nerve of vision is not a true
nerve; more a nerve tract
II.
oculomotor: innervates 4 of the extrinsic eye muscles (muscles that move the
eyeball in the orbit)
III.
trochelar: innervates an extrinsic eye muscles that hooks through a pulley-shaped
ligament in the orbit
IV.
trigeminal: provides general sensory innervation to the face and motor
innervation to the chewing muscles (has 3 major branches)
V.
abducens: innervates the muscle that abducts the eyeball (turns the eye laterally)
VI.
facial: innervates the muscles of facial expression as well as other structures
VII.
vestibulocochlear: sensory nerve of hearing and equilibrium (once classed
auditory nerve)
VIII.
glossopharyngeal: innervates tongue and pharynx
IX.
vagus: wanders beyond the head into the thorax and abdomen
X.
accessory: originates from the cervical region of the spinal cord, enters the skull
through foramen magnum, exits the skull with vagus nerve; carries motor
innervation to trapezius and sternocleidomastoid muscles
XI.
hypoglossal: runs inferior to the tongue and innervates the tongue muscles
XII.
reading 13: cranial nerves (431-439)
Monday, November 5, 2018
11:16 AM
Oh, Oh, Oh, To Touch And Feel Very Good Velvet, AH
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cranial nerves contain sensory and motor nerve fibers that innervate the head
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cell bodies of the sensory neurons lie either in receptor organs or within cranial
sensory ganglia which lie along some cranial nerves (V, VII-X), external to the
brain
comparable to the dorsal root ganglia on the spinal nerves
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cell bodies of most cranial motor neurons occur in cranial nerve nuclei in the
ventral gray matter of the brain stem
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12 cranial nerves can be classified into 3 functional groups:
primarily or exclusively sensory nerves (I, II, VIII): contain special sensory
fibers for smell (I), vision (II), and hearing and equilibrium (VIII)
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primarily motor nerves (III, IV, VI, XI, XII): contain somatic motor fibers
to skeletal muscles of the eye, neck and tongue
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mixed (motor and sensory) nerves (V, VII, IX, X): supply sensory
innervation to the face (through general somatic sensory fibers) and to the
mouth and viscera (general visceral sensory) including the taste buds for
the sense of taste (special visceral sensory); these nerves also innervate
pharyngeal arch muscles (somatic motor), such as chewing muscles (V)
and muscles of facial expression (VII)
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cranial nerves III, VII, IX, and X contain visceral motor fibers that regulate
visceral muscles and glands throughout the body
these motor fibers belong to parasympathetic division of ANS
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