Globe, Ocular tunics, and cornea, limbus and sclera Flashcards
Identify the different layers of the globe and structures that form them
Globe- eye ball Ocular tunics- outer, middle, inner Outer: contains cornea/sclera Middle: uvea (iris, ciliary body, choroid) Inner: retina
Appreciate the purpose and functions of the eye as an organ
Globe of the eye receives light in the cornea, focused on the lens back to the retina, the optic nerve relays the information to the brain
Recognize the different cell and tissue types in the cornea and how they function to maintain clarity and protect the interior structures of the globe.
limbus
highly organized stroma, able to withstand continual insult
avascular
anterior chamber contains the aqueous humor (clear)
eye
organ of sight
fibrous tunic
outer coat of the eye; includes the cornea (transparent) and the sclera (opaque)
Made up of dense CT; Cornea- holds content of eye, allows light to come in & refracts light
uvea
composed of the iris, ciliary body, and the choroid
cornea
transparent structure, bends light rays toward the center of the eye
sclera
opaque area around cornea; “white of the eye”
vascular tunic
Choroid=posterior uvea
i. serves to nourish/remove waste materials from retina and shields light from outside; enhances light through cornea
Iris and ciliary body= anterior uvea
i. both richly vascular; supports inner components of eye
ii. aqueous bathes lens moves through 2 anterior chamber back to ciliary body and builds up a pressure keeping it firmly distended
iii. CB anchors lens & provides blood-aqueous barrier
iv. iris=most anterior part= modified flap of CB -> vascular, has muscle (same in CB)
1. muscle in iris controls amount of light going back
(w/ light pupil closes, dark it opens)
neurosensory tunic
composed of the retina, inner epithelia, optic nerve
a. CNS
b. Firmly establishes eye as anterior extension of CNS
(diencephalon)
epithelium
3 cell types; basement membrane attaches it to the stroma; acts as a barrier to the precorneal tear film
stroma
90% of the corneal thickness, relatively acellular; contains collagen fibers
endothelium
secretes BM
inner part of the cornea, 1 cell layer thick
contains pump to keep cornea dehydrated
edema present if it is damaged
globe
round part of the eye
refraction
aqueous humor allows for light refraction