CH14: Cranial nerves 1 Flashcards Preview

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Flashcards in CH14: Cranial nerves 1 Deck (38):
1

Cranial nerves exchange info between

PNS CNS

2

types of functions of cranial nerves

sensory
motor
autonomic

3

How do cranial nerves differ from spinal nerves?

specialization
- motor only
- sensory only
- both

4

4 functions of cranial nerves

- supply motor to muscles of face, eyes, tongue, jaw, and 2 neck muscles

- transmit somatosensory info from skin, muscles of face, and from TMJ

- transmit special sensory info

- parasympathetic regulation

5

What special sensory info is transmitted by cranial nerves?

info related to sensations
- visual
- auditory
- vestibular
- gustatory
- olfactory
- visceral

6

What parasympathetic regulation is provided by cranial nerves?

- pupil size
- curvature of lens
- HR
- BP
- breathing
- digestion

7

Which two cranial nerves area actually considered part of the CNS? What are their functions?

- olfactory: smell
- optic: vision

8

Much of info attributed to taste is from here.

olfactory

9

Why is olfactory nerve such a big contributor to taste?

because the information from taste buds is limited to chemoreceptors for

- salty
- sweet
- sour
- umami (i.e., “savory”)
- bitter

10

retina

inner layer of posterior eye

11

What happens to light striking the retina (overall)?

converted into neural signals by photosensitive cells

12

Visual signals sent to the midbrain are involved in

- reflexive responses of the pupil
- awareness of light and dark
- orienting the head and eyes

13

Where are visual signals sent from the retina?

- lateral genticulate body (thalamus)
- nuclei in midbrain

14

Axons in the retina send neural signals through this path

- down optic nerve
- through optic chiasm
- into the optic tract

*synapse in the lateral geniculate body

15

Which CNs are lumped together?

III, IV, VI

16

Why are CNs III, IV, and VI lumped together?

All contain motor neuron axons innervating the six extraocular muscles that move the eye and control reflexive constriction of the pupil

17

rectus muscles attach to

anterior half of eyeball

18

oblique muscles attach to

posterior half of eyeball

19

How many rectus muscles?

4

20

How many oblique muscles?

2

21

CN III controls these eye muscles

- levator palpebrae superioris
- superior rectus
- medial rectus
- inferior rectus
- inferior oblique
- pupillary sphincter
- ciliary

22

CN IV controls these eye muscles

superior oblique

23

CN VI controls these eye muscles

lateral rectus

24

function of levator palpebrae superioris

lifts eyelid

25

function of superior rectus

pupil up

26

function of medial rectus

pupil medial

27

function of inferior rectus

pupil down

28

function of inferior oblique (if eye is adducted)

pupil up

29

function of inferior oblique (if eye abducted)

rotates eye

30

function of pupillary sphincter

constricts pupil

31

function of ciliary

increases lens curvature

32

function of superior oblique (if eye adducted)

pupil down and in

33

function of superior oblique (if eye abducted)

rotates eye

34

function of lateral rectus

pupil lateral

35

Head and eye movements are coordinated by signals in

the medial longitudinal fasciculus

36

When does the ciliary muscle contract? Why?

- when viewing objects closer than 20 cm
- increase curvature of lens

37

What is the action of the ciliary muscle called?

accommodation

38

What is accommodation?

increases refraction of light rays to ensure that the focal point will be maintained on the retina