structures that secrete tears and drain them from the surface of the eyeball
extrinsic eye muscles
skeletal muscles that attach to the outside of the eyeball and bones of the orbit
intrinsic eye muscles
smooth muscles located within the eye
regulates size of pupil; colored part of the eye that consists of smooth muscle fibers that form a doughnut-shaped structure; attaches to the ciliary body
controls shape of lens
outer layer; tough, white, fibrous tissue
outer layer; the transparent anterior portion that lies over the iris; no blood vessels found
middle layer; pigmented membrane lining more than two thirds of the posterior fibrous outer coat
thickening of choroid; fits between the anterior margin of retina and posterior margin
attached to the ciliary processes and blends with the elastic capsule of the lens to hold it in place
second cranial nerve extends from eyeball to brain
retina blood vessels
critical to normal visual function
contains aqueous humor; space anterior to the iris and posterior to the cornea
contains vitreous humor; small space posterior to the iris and anterior to the lens
small depression in the center of a yellowish area
macula (macula lutea)
yellowish area found near center of retina
optic disk (blind spot)
small circular area in the posterior part of the eyeball; light rays striking this area cannot be seen
hole-shaped opening in middle of iris; controlled by the iris to adjust amount of light
helps refract light to be focused on the retina
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