Structure and function: eye

accommodation

process that allows the shape of the lens to change for near and far vision

aqueous humor

watery substance filling that space between the lens and the cornea

canthus

angle where the upper and lower eyelids meet

choroid

opaque middle layer of the eyeball

ciliary body

set of muscles and suspensory ligaments that adjust the shape of lens

cones

color receptors on the retina that have high visual acuity

conjunctiva

mucous membrane covering the anterior of the eyeball and inner eyelid

cornea

transparent shield of tissue forming the outer wall of the eyeball

dacryocyst

dilated upper portion of nasolacrimal duct; tear sac, lacrimal sac

extraocular muscles

muscles within the orbit but outside the eyeball

eyebrows

arched line of hairs on the superior edge of the orbit

eyelashes

stiff hairs projecting from the margins of the eyelids

eyelids

moveable folds that cover the front of the eyes when they close

fovea centralis

a depression in the middle of the retina that is the area of sharpest vision

iris

anterior part of the vascular tunic (colored)

lacrimal apparatus

lacrimal gland, lacrimal lake, lacrimal canaliculi, lacrimal duct, nasolacrimal duct

lacrimal ducts

channels that carry tears to the eyes

lacrimal glands

glands that secrete tears

lacrimal fluid

a watery, physiologic saline (tears)

lateral angle of eye

angle formed by the union of the lateral parts of the upper eyelid and lower eyelid (lateral canthus)

lens

refractive structure of the eye, between iris and the vitreous humor

medial angle of eye

angle formed by the union of the upper eyelid and lower eyelid (medial canthus)

nasolacrimal ducts

ducts that carry tears form the lacrimal glands to the nose

optic disc

oval area in eye without light receptors (blind spot)

optic nerve

the cranial nerve responsible fo rvision

orbit

bony depression in the skull that houses the eyeball

palpebra

eyelid

photoreceptors

retinal cones and rods

pupil

dark part in the center of the iris through which light enters the eye

retina

light-sensitive membrane forming the innermost layer of the eyeball

rods

black and white receptors on the retina that responds to dim light

sclera, plural, sclerae

the outer surface of the eye; part of the fibrous tunic; white part of the eye

uvea

vascular layer of the eye

vitreous body

a transparent jellylike substance filling the interior of the eyeball

vitreous humor

fluid component of the vitreous body