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60 terms

Orbit and Eye part 2

gray's chapter 8 Ross histology chapter
STUDY
PLAY
where in the eye is the highest visual acuity
fovea centralis
eye development
optic vessels from evagination of forebrain-> contact surface ectoderm-> induction of lens placodes->lens vesicle
optic cup from optic vesicle->choroid fissure (pigmented layer of retina)
fissure allows hyaloid artery
the developing retina is part of
CNS
where is site of future retinal detachment in developing eye
intrretinal space
which artery becomes the central artery of the retina
hyaloid
what induces the formation of corneal epithelium
developing lens tells the overlying ectoderm
origin of most of the cornea
mesoderm
what forms from the loose mesenchyme around the eye primordium
inner choroid-contin with pia & arachnoid of optic nerve
outer scleral- contin w/dura of optic nerve
what layer forms the extraocular eye muscles
mesoderm
outermost layer of eye
fibrous coat
sclera
cornea
sclera
dense ct
bundes of collagen parallel to eye
cornea
transparent, avascular
middle layer of eye
vasular coat or uveal tract
choroid, ciliary body, iris
innermost layer of eye
retina
limbus cornea
area betw cornea and sclera
vascular
neuroretina
cns
10 layers
ora serrata
transition from 10 layer to 2 layered nonsensory retina
5 layers of cornea
corneal epithelium
Bowman's layer (basal lamina)
stroma (thick!)
Descemet's membrane
corneal endothelium (no bv)
nutrients to cornea come from
tear layer
aqueous humor
transition of myelinated to unmyelinated neurons in cornea
stroma->unmy as they cross bowman's layer
composition of cornea stroma
collagen lamellae wtih fibroblasts/ecm
what does the transparency of the cornes depend on
arrangement of collagen and ecm affinity for water
opaque without water
cornea endothelium permeable to
air/O2
uses 30% glucose
choroid
spongy, brownish
4 layers
4 layers of choroid
Bruch's membrane (lamina elastica)-5 layers
choriocapillaris-capillaries to nourish outer retina
vessel layer-larger vessels
epichoroid- near sclera
5 layers of Bruch's membrane
basal lamina of pigmented ep of retina
collagen
elastic
collagen
basal lamina of choroidal capillaries
what produces aqueous humor
ciliary processes of bodies
inner layer of ciliary process
nonpigmented
faces post chamber
outer layer of ciliary process
pigmented
faces stroma of ciliary body
2 surfaces of iris
ant- no epithelium
post- 2 layers of pigmented ep continuous with retina- contains melanocytes, myoepithelial cells (dilator pupillae)
fixed/dilated pupils
do not respond to light
unopp action of dilator pupillae(symp)
brainstem damage in edinger westfall nucleus
features of Horner's syndrome
ptosis- droop from denervated Muller's muscle
anhidrosis
miosis
innervation path of dilator pupillae
postgang symp from superior cervical ganglion- pregang in interomedial cell column of T1 spinal cord (uncrossed)
myoepithelial cells in indeterminant layer ant to pigmented layer
presbyopia
lens loses flexibility, can't thicken
farsightedness (older ppl)
3 parts of lens
capsule
subcapsular epithelium
lens substance
10 layers of neuroretina outside-in
1 pigmented epithelium
2 rods/cones
3 external limiting membrane (Muller cells)
4 external nuclear layer
5 external plexiform layer
6 internal nuclear (synapse Muller nucei)
7 internal plexiform
8 ganglion layer
9 optic nerve fiber layer
10 inner limiting membrane
which neuroretina layer can have astrocytes
9-optic nerve layer
functions of pigmented epithelium of retina
absorb light/prevent reflection
store/release Vit A
phago membrane from photoreceptor lamellae
what is indicated in retinitis pigmentosa
failure of phago of photoreceptor membrane, build up of debris
rods
more
all over neuroretina
low light
cylindrical outer segments-lamellae w/disc of rhodopsin, embedded in pigment epithelium, constantly being turned over
thin neck to inner, mito
what phagocytoses the old lamellae at rod tip
pigment epithelial cells
cones
fewer
most in fovea centralis
visual acuity and color
tapered outer segments- infoldings of plasma mem
what inhibits the migration of oligodendroglial cells in eye
lamina cribosa
bs to outer retina
pigmented ep and receptors supplied by choriocapillaries of choroid layer
bs to inner retina
central retinal artery
wet age related mac degeneration
10%
severe- most vision loss
0.2mill in US
sep photoreceptors from bs
dry age related mac degeneration
90%
1.8mil in us
drusen
accumulation of material between Bruch's membrane and pigmented epithelium
DRY ARMD
in wet, bv grow up and cause further sep
test for armd
amsler grid
detached retina
betw pigmented ep and photoreceptors
photo have no bs, die
papilledema
inc intracranial pressure cause optic disc/papilla to bulge into eye
anterior chamber of eye
cornea to lens
lateral border is trabecular meshwork (pectinate ligament) leading to canal of Sclemm
posterior chamber of eye
iris to lens
lateral by zonule/ciliary processes
open angle glaucoma
major cause of blindness
myopia and diabetes inc risk
angle of ant appears normal
blocked canal of Schlemm
gradual
closed angle glaucoma
rarer
ant angle blocked by iris
constricted pupil-angle is open
dilat pupil- angle closed
sudden emergency
ocular pain, blurred vision, hlos or rings around lights
optic cupping
inc intraocular pressure from glaucoma
pale optic disc
disc enlarged
retinal atrphy/neuronal death
vitreal body
transparent, jelly fills vitreous chamber
99%water
collagen, glycosaminoglycans
hyalocytes make coll and glycosamino
keeps retina in proper position
floaters
deposits in vitreous
prob vitreal proteins
benign
sudden app = serious disease
loss of vitreous humor
replace with saline to keep retina in place and maintain eyeball shape
vitrectomy
removal of cloudy/bloody vitreous