where is the eye derived from
meso and ectoderm
what is mesodermally derived
fibrous coats
ectoderm creates
lens retina cornea and pigmented layers
how many tunics
3
name the 3 tunics
fibrous, vascular, and nervous/retina
fibrious tunic is composed of
sclera and cornea
what is sclera
white part of eye
what is role of sclera
- maintain shape if inside eye pressure increases
- tiny openings allow structures to pass through
what structures pass through the eye
blood vessels
neurons
what attaches to the sclera
extra ocular muscles
anteriorly: what is sclera lined w/….what are the transitions between
conjunctiva, transition to cornea at limbus
posteriorly: continuous w/ fibrous sheath that covers which cn
2
what part of sclera is opaque
sclera
what is the anterior part called
cornea
describe cornea
clear, transparent
primary role of cornea
refractory
convex anterior or post
ant
list the 5 layers of cornea from ant to post
corneal epithelium, anterior limiting lamina, substantia propria, posterior limiting lamina, endothelium
what part is composed of the choroid, ciliariary body, and iris
vascular tunic
choroid blood supply
rich
where is choroid firmly attached to sclera
where the optic nerve penetrates it
what is special about choroid and light
it is dark pigmented to limit the passage of light
what is the ciliary body continuous with
choroid and iris
what does the ciliary body produce
aqueous fluid and GAGs of vitrous body
contraction of ciliary muscle allows lens to become ____ allow for ________ vision
convex; near
what is the colored part of the eye
iris
which part of eye has cooling effect
choroid : vascular tunic
where is ciliary muscle located
ciliary body
which two muscles are in the iris
sphicter pupillae and dilator pupillae
what suspends the lens
ciliary body
which iris muscle is regulated by para ; symp
sphincter pupillae; dilaror pupillae
retina is the outgrowth of..
diencephelon
what does retina contact internally, externally
vitreous body, choroid
10 layers of retina: external to internal
pigmented layer rods and cones external limiting membrane outer nuclear layer outer plexiform layer inner nuclear layer inner plexiform layer ganglion cell layer nerve fiber layer internal limiting membrane
name 5 cells involved in vision pathway
photoreceptors inner nuclear layer cells ganglionic layer cells lateral geniculate body brodman area 17 of occipital lobe
what structures are available on funduscopic exam
optic disc, macula lutea
t/f optic disc contains no photoreceptors
t
what is the darker area at the center of the fundus
macula lutea
what is the middle of the maculae lutea
fovea centralis
where does the optic nerve attach to the eyeball
optic disc
what are the only photoreceptors in macula lutea
cones
name the refractory components of the eyeball
cornea, aqueous humor, lens, vitreous body
what is the most anterior refractory structure
cornea
what is clear fluid secreted by ciliary process found on the post part of ciliary body
aqueous humor
what is aqueous humor secreted into
posterior chamber
describe path of aqueous humor
passes through pupil into anternior chamber, then laterally, leaving eyeball through scleral venous sinus
what results from inc. pressure from anterior segment of eyeball
glaucoma
describe of lens
transparent, biconvex, avascular
t/f inc. concavity allows for near vision
f: convexity
lens gets harder w/ age->more difficult ___ vision
presbyopia; near
lens becomes less transparent
cataracts
what fills posterior segment
vitreous body
what connects optic n and post aspect of lens
hyaloid canal
what seperates anterior segment from posterior segment
lens
hyaloid canal is fxnal infetuses or adults
fetuses, contained fetal hyaloid artery
accessory structures of the eye
extraocular muscles, lacrimal appararus, tarsal glands
name parts of lacrimal appararus
lacrimal glands, lacrimal ducts, lacrimal sac, nasolacrimal duct
what secretes tears
lacrimal glands
what drains tears and to where
lacrimal ducts; lacrimal sac
lacrimal sac is where
groove between lacrimal bone and maxilla
nascolacrimal duct drains tears to
interior nasal meatus
where are tarsal glands
located in each eyelid
all arteries to eye are branches of
opthalmic artery
what artery runs between sclera and cornea
long posterior ciliary artery, medial and lateral
what is purpose of tarsal glands
reduce evaporation of tears through release of oily substance
how many arteries form a ring around the optic nerve
6-12 short ciliary
which arteries arch over/under eyeball
3-4 over 3-4 under
anterior ciliary arteries
what does the central retinal artery travel w/
optic nerve
name veins that drain the eye
anterior ciliary, long posterior ciliary, central retinal vein
which branch of V supplies the eye
nasociliary of ophthalmic divison
what is sensory for ciliary body, iris, and cornea
long ciliary nerves
what is the only artery that supplies retina
central retinal artery
what nerves are sensory for the eyeball
short ciliary nerves
t/f post para fibers follow a similar path as symp and supply the ciliaris and dilator pupillae
f: sphincter pupillae
post symp fibers from which plexus reach ciliaris and dilator pupillae
cavernous