Eye Anatomy Flashcards
Eye
description? how many layers? what are they?
2.5 diameter wall of eyeball consists of 3 layers: -fibrous tunic: outer layer -vascular tunic: middle layer -retina: inner layer
Fibrous Tunic
composed of ? (2)
cornea
sclera
Cornea
description? what does it do?
transparent covering of iris
admits & refracts light into eye- helps focus light onto retina
(bulges out)
Sclera
description? what does it do?
(cornea turns into this)
“white” of the eye- dense connective tissue
provides shape to eyeball (outer layer)
attachment for eye muscles
Vascular Tunic (Uvea) composed of ? (3)
(called Uvea bc of UV light)
choroid
ciliary body
iris
Choroid
function? location? description? contains? which do what?
lines sclera
posterior portion of tunic
vascular
contains melanocytes- appears black/brown
-prevents reflection & scattering of light
Ciliary body
anterior portion of tunic contains melanocytes (dark brown appearance) parts: -ciliary processes -ciliary muscle
ciliary processes definition?
vascular folds of internal surface of ciliary body
- secretes aqueous humor (watery)
ciliary muscle definition ?
(connected to iris)
circular band of smooth muscle
-muscle contraction changes lens shape
-adapts for near or far vision
iris
description? how is color determined? location? made of? function?
colored portion of eyeball -determined by amount of melanin attached to ciliary processes made of melanocytes & smooth muscle fibers regulates amount of light into eyeball
pupil
opening in center of iris\
coloboma
irregular shaped iris
-pupil is NOT circular
(does not affect sight, happens in fetus)
heterochromia iridum
2 different colored iris
EX: blue and green eye
Lens, is it part of vascular tunic?
No, its not a part of the vascular tunic, it only sits in that area
Lens
description?
contains?
function?
(hard & semi-transparent) behind pupil & iris contains proteins - crystallins -arranged in layers lacks blood vessels helps focus images on retina (help focus light on it)
Interior eyeball cavities
whats divided into 2 cavities? what are they?
lens divides eye into 2 cavities : anterior cavity vitreous chamber (posterior cavity)
Anterior cavity
filled with? functions?
(watery)
filled w/ aqueous humor
-maintains shape of eyeball
-supplies oxygen & nutrients to lens & cornea
Posterior cavity aka Vitreous Chamber
(jelly) Large cavity behind lens -filled w/ vitreous body -jelly-like substance -maintain shape of eyeball -keeps retina attached to choroid
how are the cavities held together?
held together by pressure
retina
description? consists of?
inner layer of eyeball, posterior 3/4 of eyeball
Consists of:
-pigmented layer- melanin
-neural (sensory) layer- processes visual data
Pigmented layer
(contains melanin)
helps absorb light rays
Neural (sensory) layer
(processes visual data) 3 layers: -Photoreceptors (rods & cones) -Bipolar cell layer -Ganglion cell layer
Other Areas on Retina (3)
Macula lutea
Fovea centralis
Optic disc
Macula lutea
description? location?
small flat spot
exact center posterior region of retina
visual axis of eye
Macular Degeneration (in macula lutea) where does it occur? what is it? what happens?
Degenerative disorder of retina
- occur in region of macula lutea
- lose acute vision, but have peripheral vision
Fovea centralis
location? contains? known for?
small depression in center of macula lutea
contains ONLY CONES
area of highest visual resolution