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Cell Bio Eye
KYCOM Block 4
171
Biology
Graduate
12/06/2012

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Term
what are the layers of the eye
Definition
coneosclear coat, vascular coat, retina
Term
what is the outer fibrous layer of the eye
Definition
corneoscleral coat
Term
what does the corneoscleral coat ccontain
Definition
sclera 9white0 and cornea (clear)
Term
what is the middle layer of the eye called
Definition
vascular coat or uvea
Term
what does the vascular coat include
Definition
choroid, stroma of the ciliary body and iris
Term
what is the inner layer of the eye called
Definition
retina
Term
what does the retina include
Definition
outer pigment epithelium, inner neural layer, epithelium of the ciliary body and iris
Term
what are the chambers of the eye
Definition
anteriorn, posterior, and vitreous
Term
what forms the anterior chamber of the eye
Definition
space between cornea and iris
Term
what forms the posterior chamber of the eye
Definition
space between the posterior surface of the iris and the anterior surface of the lens
Term
what forms the vitreous chamber of the eye
Definition
space between posterior surface of the lens and the neural retina
Term
what and when does the eye appear as
Definition
shallow grooves called optic sulci or grooves on day 22
Term
what happens to the optic sulci or grooves
Definition
as the neural tube closes, they form outpocketings called optic vesicles
Term
as the optic vesicles form laterally, what is happening at the other end of the developing eye
Definition
connection to the forebrain becomes constricted to form an optic stalk and the overlying ectoderm thickens and forms and lens placode
Term
how is the optic vesicle turned into two eyes
Definition
the lens placode and optic vesicle invaginate forming a double layered optic cup
Term
what does the inner layer of the optic cup become
Definition
neural retinal
Term
what does the outer layer of the optic cup become
Definition
retinal pigment epithelium
Term
where do grooves containing blood vessels for the eye come from, where
Definition
mesenchyme along inferior surface of each optic cup
Term
what are the grooves with vessels in the developing eye called
Definition
choroid fissures
Term
what do choroid fissures function to do
Definition
allow hayloid vessels to reach the inner chamber of the eye
Term
what ultametly happens to the hayloid vessels
Definition
distal part degenerates and proximal part remains as the central vessels of the retina
Term
during the third month of gestation what does the optic cup make
Definition
ciliary body and iris
Term
where do the dilator and sphincter pupillary muscles appear
Definition
month 6
Term
what is hte iris light blue at birth
Definition
because pigment isnt usually present yet
Term
what is the key regulatory gene for eye development
Definition
PAX6
Term
what initiates formation of the ridge on the neural plate that forms a single eye field
Definition
PAX6
Term
what does the single eye field seperate into
Definition
two optic primordia
Term
what signals for seperation of the eye field
Definition
SHH
Term
what in the eye comes from the surface ectoderm
Definition
lens, epithelium of cornea, conjunctiva, lacrimal gland and its drainage system
Term
what in the eye comes from the neural ectoderm
Definition
vitreous body, epithelium of retina iris and ciliary body, sphinctor pupillae, dilatory pupillae, optic nerve
Term
what in the eye comes from the mesoderm
Definition
sclera, stroma of the cornea ciliary body iris and choroid, extraocular muscles, eyelids, hayloid system, coverings of the optic n, ct and vessels of the eye bony orbit and vitreous body
Term
what is coloboma
Definition
cleft in iris
Term
whwhat is congenital cataracts
Definition
lens becomes clouded during intrauterine life
Term
what can cause congenital cataracts
Definition
maternal rubella infection
Term
what is microphthalmia
Definition
the eye is too small
Term
what causes microphthalmia
Definition
cytomegalovirus and toxoplasmosis
Term
what is anophthalmia
Definition
absence of the eye
Term
what is anophthalmia usually accompanied by
Definition
severe cranial abnormailities
Term
what is congential aphakia
Definition
absence of lens
Term
what can cause congenital aphakia
Definition
mutation in PAX6
Term
what is cyclopia or synophthalmia
Definition
fusion of the eyes
Term
what is cyclopia or synophthalmia usually associated with
Definition
holoprosencephaly
Term
why are the eyes fused in cyclopia or synophthalmia
Definition
loss of midline structures prevented the eye fields from seperating
Term
when does loss of midline structures in cyclopia or synophthalmia occur
Definition
19-21 days
Term
what are factors that affet midline structure loss
Definition
alcohol, mutations in SHH, abnormailities in cholesterol metabolism that disrupts SHH
Term
what is aniridia
Definition
absence of iris
Term
what can cause aniridia
Definition
mutations in PAX6
Term
what disease in aniridia a part of
Definition
WAGR syndrome
Term
what does WAGR syndrome consist of
Definition
wilms tumor, aniridia, genitourinary abnormailities, retardation
Term
what is wilms tumor
Definition
can cer of the kidney the usually affects children of 5 years but also in the fetus
Term
what are the layers of the cornea
Definition
corneal epithelium, bowman's membrane, corneal stroma, descemet's membrane, corneal endothelium
Term
what type of tissue is the corneal epithelium
Definition
non keratinized stratified squamous epithelium
Term
what is the corneal epithelium attached to, by what
Definition
bowman's membrane by hemidesmosomes
Term
what is bomans membrane
Definition
anterior basement membrane
Term
where is the bowmans membrane
Definition
between corneal epithelium and underlying corneal strma
Term
where does bowmans membrane end
Definition
abruptly at the corneoscleral limbus.
Term
what is the function of bowmans membrane
Definition
barrier to spread infection
Term
what is another name for the corneal stroma
Definition
substantia propria
Term
what does the corneal stroma consist of
Definition
layers of parallel bundles of collagen, avascular
Term
where is the corneal stroma
Definition
between flattened fibroblasts
Term
what is descemet's membrane
Definition
posterior thick basement membrane
Term
what is the function of the corneal endothelium
Definition
metabolic exchange between cornea and aquous humor
Term
what is the sclera mostly made of
Definition
dense CT
Term
what does the sclera contain
Definition
dense CT, collagen bundles, elastic fibers and ground substance between collagen
Term
how is the collagen of the sclera oriented
Definition
various directions and in pannels to the surface elastic fibers and ground substance between collagen
Term
what pierces the sclera
Definition
blood vessels, nerves, optic nerve
Term
what do the tendons of the extraocular muscles insert into
Definition
sclera
Term
what is the corneoscleral limbus
Definition
transitional zone between cornea and sclera
Term
how does the cornea and sclera combine at the edges
Definition
corneal layers merge with collagen bundles of sclera
Term
describe the transition of the vasculature at the corneoscleral limbus
Definition
abrupt transition from avascular cornea to highly vascularized sclara
Term
where is the outflow apparatus for the aquous humor
Definition
limbus region, iridocorneal angle
Term
what forms the scleral venous sinus
Definition
endothelium lined channels called trabecular network merge
Term
what is another name for scleral venous sinus
Definition
canal of schlemm
Term
where is the canal of schlemm
Definition
encircles the eye
Term
what is the function of the canal of schlemm
Definition
drains squous humor from the anterior chamber
Term
what is the most anterior part of the vascular coat
Definition
itis
Term
where does the iris come from and attach to
Definition
anterior border of ciliary body and is attached to sclera at the corneoscleral junction
Term
what is the central aperature of the iris
Definition
pupil
Term
what does the iris consist of
Definition
highly vascularized CT stroma covered on posterior surface by highly pigmented cells
Term
what are the highly pigmented cells on the posterior iris called
Definition
posterior pigment epithelium
Term
where does color in the eye come from
Definition
light reflected from the pigment present in the cells of the posterior surface of the regina giving it a blue apperance. more pigment leads to a darker color
Term
what is the ciliary body part of
Definition
vascular coat
Term
what is the ciliary body between
Definition
iris and choroid
Term
what are ciliary processes
Definition
ridges with zonular fibers that attach to the lens
Term
what covers the ciliary body
Definition
ciliary epithelium
Term
what type of tissue is ciliary epithelium
Definition
double layer of columnar
Term
what are the functions of ciliary epithelium
Definition
secretes aquous humor, blood aquous barrier, secrete and anchor zonular fibers to form suspensory ligament of the lens
Term
what do the non pigament cells of the ciliary body do
Definition
fluid transport
Term
how are the non pigmented cells of the ciliary body held down
Definition
cell cell junctions with zona occludins and lots of basal and lateral infoldings
Term
how are pigmented cells of the ciliary body held in
Definition
less developed junctions, irregular intercellular spaces
Term
what holds the apical surfaces of ciliary cells togather
Definition
desmosomes and gap junctions
Term
what are the discontinous gaps between ciliary cells called
Definition
ciliary channels
Term
what is the aquous humor a derivative of plasma
Definition
plasma
Term
explain the path of the aquous humor
Definition
passes ciliary body, goes to between iris and lens before the anterior chamber,in chamber it goes from cornea to iris and penetrates tissue of limbus to make the trabecular meshwork which turns into canal of schlemm
Term
what does the canall of schlemm run with
Definition
veins of sclera
Term
in general, what causes glaucoma
Definition
obstruction of the drainage of the aquous humor increasing intraocular pressure causing retina damage and ultametly blindness
Term
what are the symptoms of glaucoma
Definition
pain, nausea, blurred vision, halos
Term
what is the most common form of glaucoma
Definition
open angle
Term
what occurs in open angle glaucoma
Definition
trabecular meshwork drains aquous homor but schlemm is blocked
Term
what occurs in closed angle glaucoma
Definition
aquous humor cant go to trabecular meshwork because of inflammation of uvea. it never gets to the schlemm
Term
how is glaucoma treated
Definition
trabeculoplasty: laser burns holes in trabecular mesh around limbus to restore fluid flow, carbonic anhydrase inhibitors
Term
what do carbonic anhydrase inhibitors do
Definition
stop carbonic anhydrase isomerase which makes aquous humor
Term
what happens in pressure in the eye is not relived
Definition
retinal nerve fiber atrophy
Term
where is the choroid located
Definition
vascular coat, between sclera and retina
Term
what are the layers of the choroid
Definition
choricocapillary and burch's membrane
Term
where is the choricocapillary in the choroid, what is it made of
Definition
inner vascular layer
Term
where is the burch's membrane in the choroid, what is the made of
Definition
outer thin hayline layer
Term
what are the cells of the retina
Definition
photoreceptors, conducting neurons, association/other, supporting
Term
what are the photoreceptor cells
Definition
rods, cones
Term
what are the conduction neuron cells
Definition
bipolar, ganglion
Term
what are the association / other cells of the retina
Definition
horizontal, centrifugal, interplexiform, amacrine
Term
what is another name for the supporting cells of the retina
Definition
neuroglial
Term
what are the supporting cells of the retina
Definition
muller, microglial, astrocytes
Term
what are the 10 layers of the retina
Definition
1. retinal pigmented epithelium
2. rods and cones
3. outer limiting membrane
4. outer nuclear layer
5. outer plexiform layer
6. inner nuclear layer
7. inner plexiform layer
8. ganglion cell layer
9. optic nerve fibers
10. inner limiting membrane
Term
what layer of the retina is not part of the retina
Definition
retinal pigmented epithelium
Term
what does the retinal pigmented epithelium do
Definition
absorb light through neural retina preventing reflection and flare, participate in the blood-retina barrier
Term
what type of cells is the retinal pigmented epithelium
Definition
1 layer of cuboid cells connected by junctions
Term
what does the retinal pigmented epithelium sit on
Definition
birch's membrane of choricoid
Term
what is in the rod and cone layer
Definition
outer and inner photo receptors
Term
what is in the outer limiting membrane
Definition
apical boundry of muller's cells
Term
what is in the outer mouclear layer
Definition
cell bodies of rods and cones
Term
what is in the outer plexiform layer
Definition
processes of rods and cones, processes of horizontal amacrine and bipolar cells
Term
what is in the inner nuclear layer
Definition
cell bodies of horizontal, amacrine bipolar, and muller's cells
Term
what is in the inner plexiform layer
Definition
process of hariz, amacrine, bipolar cells and ganglion cells that connect them
Term
what is in the genglion cell layer
Definition
cell bodies of ganglia
Term
what is in the optic nerve fiber layer
Definition
axons of genglia cells from retina to brain
Term
what is in the inner limiting membrane
Definition
basal lamina and muller cells
Term
which is more sensitive to light rods or cones
Definition
rods
Term
what do rods percieve
Definition
low light, gray tones
Term
what do cones percieve
Definition
reb, gree, blue, or their mixture
Term
what photoreceptors form in development first
Definition
cones
Term
what is the forva centralis
Definition
depression of the retina
Term
what is the foveola
Definition
central part of the forva made of all cones
Term
what is the macula lutea
Definition
region around the foeva
Term
why is the macula lutes yellow
Definition
because of the xanthophyll pigment
Term
where in the retina are there no retina vessels
Definition
macula lutea
Term
what is another name for the optic disc
Definition
papilla
Term
what is in the optic dics
Definition
optic n
Term
what is the blind spot, why
Definition
optic disc because it has no photo receptors
Term
what happens in retinal detachment
Definition
potential space between optic cup layers expands and retina pulls away from retinal pigmented epithelium
Term
what are floaters, why are they there
Definition
in retinal detachment no nutrients get to the photoreceptors from choricocapillary plexus of chorcoid and floaters are released RBC that are injured
Term
if the retina is not re attached what happens after some time
Definition
blindness
Term
define cataracts
Definition
change in solubility of lens protein decreasing opacity
Term
what increases cataract risk
Definition
age, diabetes
Term
how does diabetes cause cataracts
Definition
glucose increases and it is a metabolite for the eye and is turned into sorbitol and it accumulates decreasing solubility of proteins and opacity
Term
what does cataracts do to vision
Definition
scatters light
Term
what is hte vitreous body
Definition
transparent jelly in vitreous chamber posterior part
Term
what is the vitreous body mostly made of
Definition
water
Term
what is the vitreous body made of
Definition
water, collagen, GAGs 9hyaluronan), hyalocytes, macrophages, fibroblasts
Term
what do hyalocytes do
Definition
make collagen fibrils and GAGs
Term
what is the most common cause of blindness in the elderly
Definition
macular degeneration
Term
what causes macular degeneration
Definition
genetics and the enivornment (uv light, drugs)
Term
what is dry macular degeneration
Definition
atrophic, nonexudative
Term
what occurs in dry macular degeneration
Definition
degenerative lesions of macula lutea
Term
what do degenerative lesions cause
Definition
focal thickening of burch's membrane, atrophy and depigmentation of retinal pigment epithelium, destory capillaries in choroid
Term
describe wet macular degeneration
Definition
exudative neurovascular, formation of vessels, a complication of dry macular degeneration
Term
what occurs in wet macular degeneration
Definition
new vessels form and are thin, fragile, and leaky leading to adudate and hemmorage in space between them
Term
how is wet macular degeneration treated
Definition
laser therapy to destory vesses
Term
describe the lens of the eye in general
Definition
avascular, biconvex, transparent
Term
what suspends the lens, what is its other function
Definition
ciliary body gives out sonular fibers that suspend and it it flat
Term
what happens if tension on the lens is released, what is this called
Definition
it plumps to allow for focus and bends light closer to the eye putting the focus on the retina. accumulation
Term
what forms junctional complexes with lens fibers
Definition
subcapsular cells
Term
what is the capsule of the lens made of
Definition
IV collagen and proteoglycans, elastic
Term
where is the capsule of the lens thicker
Definition
zonular fiber attachment and basal lamina
Term
what connects the lens to the subcapsular epithelium
Definition
gap junctions
Term
what makes the basal lamina of the lens
Definition
anterior lens cells
Term
what type of cells is the subcapsular epithelium
Definition
cuboidal
Term
where is the subcapsular epithelium
Definition
only on anterior part of lens
Term
where do lens fibers come from
Definition
subcapsular epithelium
Term
how do lens fibers change over life
Definition
in development they increase in size, as you age new ones appear and they mature
Term
how do lens fibers mature
Definition
they gety thinner, taller, lose nuclei, fill with crystalin (protein)
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