14a – Cranial Nerve Part I

Question 1

Cranial nerves and anatomical knowledge:

Answer 1

-involved in a variety of functions/systems within and outside head
-key for clinical exam and surgery of head and neck

Question 2

Peripheral nervous system (PNS) divided functionally into:

Answer 2

-afferent=sensory=impulses TOWARD brain
-efferent=MOTOR=impulses away from brain
*further divided into somatic and visceral

Question 3

Somatic (voluntary):

Answer 3

-both sensory and motor functions related to outside world
>detection of stimuli in skin and tissues
>locomotion
>behaviour
>expressions

Question 4

Visceral:

Answer 4

-both sensory and motor functions related to internal visceral
>regulation of BP, HR, glands, digestion, etc.
-motor component=ANS

Question 5

Afferent or sensory systems are divided into:

Answer 5

-general sensory
-special senses

Question 6

General sensory:

Answer 6

General sensory:
-senses of:
>PRESSURE
>stretch
>T
>noxious stimuli from tissues in body and head

Question 7

General sensory divided into:

Answer 7

-general somatic afferent/sensory (GSA)
-general visceral afferent/sensory (GVA)

Question 8

General somatic afferent/sensory (GSA):

Answer 8

-receptors in skin informing stimuli from outside
-deeper somatic tissues informing movements of muscles and body parts relative to one another
*found in all spinal nerves and CN V

Question 9

General visceral afferent/sensory (GVA):

Answer 9

-receptors in vessels, glands and viscera of head and trunk
>informing stretch and chemical stimuli
*found in all spinal nerves and CN III, IV, VII, IX, X

Question 10

Special senses:

Answer 10

-senses ONLY found in head
>vision
>audition
>TASTE
>smell
Balance

Question 11

Special senses divided into:

Answer 11

-special somatic afferent/sensory (SSA)
-special visceral afferent/sensory (SVA)

Question 12

Special somatic afferent/sensory (SSA):

Answer 12

-more restricted origin within certain special sense organs of head:
>retina of eye
>cochlear and vestibular of inner ear
*found only within CN II and VII

Question 13

Special visceral afferent/sensory (SVA):

Answer 13

-includes special senses of small and taste
-found in CN I for smell
-found in CN VII and IX for taste

Question 14

Efferent or motor systems are divided into:

Answer 14

-somatic efferent/motor
-visceral efferent/motor (aka ANS)

Question 15

Somatic efferent/motor:

Answer 15

-supply striated muscles
-found in all SN and ALL CN except those exclusively sensory nerves (I, II, VIII)

Question 16

Somatic efferent/motor in body and limbs arise from:

Answer 16

-SOMITES

Question 17

Somatic efferent/motor in head arise from:

Answer 17

-pharyngeal or brachial arches

Question 18

Visceral efferent/motor (aka. ANS):

Answer 18

-supply SMOOTH muscle of blood vessels, viscera, heart muscle and glands
-S and PS components
-many ANS fibers travel to target organs by joining other nerves

Question 19

Sympathetic fibers leave SN in:

Answer 19

-thoracolumbar regions of spinal cord

Question 20

Parasympathetic fibers found in:

Answer 20

-small group of cranial nerves (III, VII, IX, X)
-spinal nerves in sacral region of spinal cord

Question 21

Cranial nerve numbers:

Answer 21

-12 pairs of cranial nerves
-numbered ROSTROCAUDALLY
-originate from different regions of encephalon

Question 22

Where does CN I originate from?

Answer 22

-CEREBRUM

Question 23

Where does CN II originate from?

Answer 23

-diencephalon

Question 24

Where does CN III and IV originate from?

Answer 24

-mesencephalon

Question 25

Where does CN V originate from?

Answer 25

-pons

Question 26

Where does CV VI thru XII originate from?

Answer 26

-m. oblongata

Question 27

Cranial nerve names: acronym

Answer 27

-Oh
-Once
-One
-Takes
-The
-Anatomy
-Final
-Very
-Good
-Vacations
-Sound
-Heavenly

Question 28

CN I name:

Answer 28

-olfactory

Question 29

CN II name:

Answer 29

-optic

Question 30

CN III name:

Answer 30

-oculomotor

Question 31

CN IV name:

Answer 31

-trochlear

Question 32

CN V name:

Answer 32

-trigeminal

Question 33

CN VI name:

Answer 33

-abducent

Question 34

CN VII name:

Answer 34

-facial

Question 35

CN VIII name:

Answer 35

-vestibulocochlear

Question 36

CN IX name:

Answer 36

-glossopharyngeal

Question 37

CN X name:

Answer 37

-vagus

Question 38

CN XI name:

Answer 38

-spinal accessory

Question 39

CN XII name:

Answer 39

-hypoglossal

Question 40

Analogy of spinal nerve:

Answer 40

-dorsal root: only contains sensory fibers
-ventral root: only contains motor
*dorsal and ventral roots combine to form a single mixed spinal nerve

Question 41

Analogy of cranial nerves:

Answer 41

-dorsal root EQUIVALENTS also contain some motor fibers
*dorsal and ventral root equivalents remain as separate cranial nerves

Question 42

CN can be divided into:

Answer 42

-nerves of special senses
-VENTRAL root equivalents
-dorsal root equivalents

Question 43

Nerves of special sense: CNs

Answer 43

-exclusively concerned with special senses
-I, II, VIII

Question 44

Ventral root equivalents: CNs

Answer 44

-homologous with ventral spinal roots
-consists almost entirely of motor fibers
-supply striated head muscles of somatic origin
-move eye or tongue

Question 45

Number of CNs that are ventral root equivalents:

Answer 45

-III
-IV
-VI
-XII

Question 46

Dorsal root equivalents:

Answer 46

-homologous with dorsal spinal roots
-consist primarily of MIXED fibers
-supply structures of pharyngeal arch origin

Question 47

Number of CNs that are dorsal root equivalents:

Answer 47

-V
-VII
-IX
-X
-XI