A&p Ch 13 Pt 2

Front 1

–Mixed nerves

Back 1

– both sensory and motor fibers; impulses both to and from CNS

Front 2

Sensory (afferent) nerves

Back 2

– impulses only toward CNS

Front 3

Motor (efferent) nerves

Back 3

– impulses only away from CNS

Front 4

Somatic afferent:

Back 4

from skin, skeletal muscles or joints

Front 5

Visceral afferent:

Back 5

from organs within ventral body cavity (stomach, bladder, etc.)

Front 6

Somatic efferent:

Back 6

voluntary, skeletal muscle

Front 7

–Visceral efferent:

Back 7

involuntary, cardiac muscle, smooth muscle, or glands

Front 8

Crainial Nerve I

Back 8

• I. Olfactory – if damaged, loss of smell

Front 9

Crainial Nerve II

Back 9

• II. Optic – if severed, blindness in eye

served by that nerve

Front 10

Crainial Nerve III

Back 10

III. Oculomotor –if damaged: eye cannot

move up, down, or inward & at rest, eye

will rotate laterally

Front 11

Crainial nerve IV

Back 11

IV. Trochlear – controls superior oblique

muscle; if damaged results in double

vision & reduced ability to rotate eye

inferior & lateral

Front 12

Cranial nerve V

Back 12

V. Trigeminal – sensory fibers to face &

motor fiber to chewing muscles;

inflammation results in most excruciating

pain known; relentless; in extreme cases,

nerve will be severed resulting in loss of

sensation to that side of face

Front 13

Cranial nerve VI

Back 13

VI. Abducens - supplies lateral rectus; if

damaged eyeball cannot be moved

laterally, at rest, eye will rotate medially

Front 14

Cranial nerve VII

Back 14

VII. Facial – supplies nerves of facial

expression; if damaged paralyze facial

muscles on affected side (Bell’s palsy,

caused by herpes simplex I virus)

Front 15

Cranial nerve VIII

Back 15

VIII. Vestibulocochlear – sensory nerve for

hearing & equilibrium;

– Cochlear damaged then nerve deafness;

– Vestibular damaged produces dizziness, loss

of balance, nausea, vomiting

Front 16

Cranial nerve IX

Back 16

IX. Glossopharyngeal –supplies nerves for

tongue (taste) & pharynx; if damaged,

impairs swallowing & taste

Front 17

Cranial nerve X

Back 17

X. Vagus – mixed only nerve to extend

beyond head & neck to supply the thorax

& abdomen;

• if damaged, loss of voice or hoarseness;

• if both vagus nerves severed, fatal

because parasympathetic shut down

Front 18

Cranial nerve XI

Back 18

XI. Accessory – supplies trapezius and

sternocleidomastoid; if damaged causes

head to turn toward injury side as result of

sternocleidomastoid muscle paralysis; also

difficult to shrug shoulders (trapezius

Front 19

Cranial nerve XII

Back 19

XII. Hypoglossal – supplies some tonguemoving

muscles: if damaged difficult to

swallowing & impairs speech; if both nerves

damaged, cannot protrude tongue

Front 20

– Neuron cell bodies within special sense organs

Back 20

Olfactory and optic nerves

Front 21

Distribution of the 31 pairs of cranial nerves

Back 21

– 8 cervical (C1–C8)

– 12 thoracic (T1–T12)

– 5 Lumbar (L1–L5)

– 5 Sacral (S1–S5)

– 1 Coccygeal (C0)

Front 22

Ventral roots

Back 22

– Contain motor (efferent) fibers from ventral

horn motor neurons

– Fibers innervate skeletal muscles

Front 23

Dorsal roots

Back 23

– Contain sensory (afferent) fibers from sensory

neurons in dorsal root ganglia and conduct

impulses from peripheral receptors

Front 24

Dorsal & ventral roots unite

Back 24

= spinal nerves

Front 25

Rami:

Back 25

contain both sensory & motor fibers

Front 26

Rami communicantes:

Back 26

contains autonomic (visceral) nerve fibers that allow communication of adjoining spinal nerves

Front 27

Plexuses

Back 27

• Network of nerves that join together; form

from ventral rami only

Front 28

4 major spinal plexuses:

Back 28

cervical, brachial, lumbar, and sacral regions, but

no thoracic!

Front 29

– This is why damage to one spinal segment

cannot completely paralyze a limb muscle

Back 29

Each muscle in a limb receives a nerve

supply from more than one spinal nerve

Front 30

Phrenic nerve

Back 30

– Responsible for contraction in breathing

• irritation of phrenic causes “diaphragm

spasms” or hiccups

• paralysis of phrenic causes respiratory

arrest

Front 31

Median—

Back 31

innervates the skin, most flexors

and pronators in forearm, and some

intrinsic muscles of the hand, damage

makes it hard to use pincer grasp frequent

casualty of suicide attempt; compressed in

carpel tunnel

Front 32

Ulnar—

Back 32

supplies forearm flexors; trauma to

ulnar damages “funny bone” results in

tingling

Front 33

Radial—

Back 33

innervates essentially all extensor

muscles, supinators, and posterior skin of

limb; trauma results in wrist drop (can’t

extend hand at the wrist

Front 34

Axillary—

Back 34

innervates the deltoid, teres

minor, and skin and joint capsule of the

shoulder

Front 35

Lumbar Plexus

Back 35

• Innervates thigh, abdominal wall, and

psoas muscle

Front 36

Femoral nerve

Back 36

—innervates quadriceps

and skin of anterior thigh and medial

surface of leg; controls muscles of hip

flexion & knee extension

Front 37

Obturator nerve

Back 37

—passes through obturator foramen to innervate adductor muscles; pain in medial thigh if nerve impaired

Front 38

Sacral Plexus

Back 38

• Serves the buttock, lower limb, pelvic

structures, and perineum

Front 39

Sciatic nerve

Back 39

– Longest and thickest nerve of body

– Innervates hamstring muscles, adductor

magnus, and most muscles in leg and foot

– Composed of two nerves: tibial and common

fibular

– if severed, cannot flex, foot drops into plantar

flexion, leg is nearly useless

Front 40

Pudendal:

Back 40

serves perineum region

(external genitalia & anus) & anal &

bladder sphincters,

– Helps stimulate erections

– Aids voluntary control of urination

Front 41

Reflexes

• Inborn (intrinsic) reflex

Back 41

- rapid, involuntary,

unlearned, unpremeditated predictable

motor response to stimulus

– Example – you splash hot water & drop the

pot before you even feel pain

– Can be modified by learning and conscious

effort

Front 42

Learned (acquired) reflexes

Back 42

result from practice or repetition,

– Example – driving skills