Visual System - Lecture 8 Flashcards
eyes are the window to the soul
brain and eye development are closely linked in utero
does the visual system create an exact copy of the external world
yes
what does the visual system create
perception of reality
how do we rely on vision
heavily for balance
–>visual, vestibular, somatosensory
what does vision do overtime
decays over time
gets worse as we get older
what is the primary CN for vision
CN2
CNs for extraocular muscles
3,4,6
binocular disparity
most mammals have 2 eyes on the front of their heads
what does binocular disparity do
cuts down the field of view
insures most of what is seen through both eyes
we can see past midline
what is slightly different b/w both eyes
perspective
difference b/w 2 retinal images
what is binocular disparity greater for
closer things
what is the degree of binocular disparity associated with
particular visual stimulus
helps the brain create 3-D perception from 2-D retinal images
can we still perceive depth with one eye close
yes
depth perception CN
2
what percentage of all sensory receptors are in the eyes
70%
what percentage of the cerebral cortex is involved in processing visual info
40%
external structures of the peripheral NS
orbit
palpebrae
orbit
bony socket
what does the orbit contain
eye
orbital fat
fascia
levator muscle of the upper lid
lacrimal gland
extraocular muscles
nerves and blood vessels
how many bones form the orbit
7
what is the palpbrae
eyelids
what do the palpbrae do
protect the eye and help replenish the tear film
what is in the palpbrae
orbicularis oculi muscle
levator palpebraer superioris muscle
orbicularis oculi muscle
occupies the entire length of the eyelid
responsible for closure
CN7
levator palpebraer superioris muscle
occupies the width of the lid
responsible for opening
CN3 (superior branch)
globe
eyeball
cornea
clear covering in front of the the colored part of the eye
protection
scleara
white of the eyes
cornea limbus
the jxn of the cornea and the sclera
conjunctiva
clear mucous membrane
deepest layer of the eyelid
ptosis
drooping of the eyelid
dz of CN3
dysfunction of the levator
normal with aging if bilateral
what does the lacrimal system do
produces and maintains the tear film
what do tears produce
smooth, optically clear surface for the cornea
helps protect the cornea
what do tears do
wash away debris and cellular waste products
nourish and protect eye from dz
tearing is controlled by
ANS
lacrimal system is innervated by
CN7
