BIOL:1141 Eye Structures and Functions

cornea

location:

• clear covering at the front of the eye

function:

• protects the eye

• works as a prism and bends light toward the pupil according to its wavelength

sclera

location:

• outer coat of the eyeball and optic nerve

function:

• protection

iris

location:

• colored part of the eye

• behind cornea

function:

• forms pupil

• regulates amount of light coming into the eye

pupil

location:

• aperture of the eye formed by the iris

function:

• changes size to regulate amount of light coming into the eye

vitreous humor

location:

• jelly-like substance between lens and retina

function:

• holds retina in place and maintains shape of the eye

• shock absorption

• clear to allow light to pass through

suspensory ligaments

location:

• black strands radiating from the lens to the ciliary muscle

function:

• connects the ciliary muscle to the lens

• holds lens in place

lens

location:

• transparent, biconvex structure behind the pupil

function:

• focuses on the retina

• shape adjusts for viewing at different distances with ciliary muscle

ciliary body

location:

• between the lens, iris, and choroid

• made up of ciliary muscle and suspensory ligaments

function:

• secretes the aqueous humor

ciliary muscle

location:

• in the ciliary body

function:

• regulates curvature of the lens to focus on far or near objects

choroid and tapetum

location:

• between the sclera and the retina

function:

• layers of blood vessels that bring nutrients and oxygen to the eye

• regulates temperature

• reflects light to aid in night vision

retina

location:

• photoreceptor cell layer

function:

• detects light with photoreceptors and sends this information to the brain as nerve impulses along the optic nerve

fovea

location:

• shallow depression in the retina

function:

• retina point with the highest resolution

rod

location:

• photoreceptor cells of the retina

function:

• black and white vision

• dim light

cones

location:

• photoreceptor cells of the retina

function:

• color vision

• bright light

optic nerve

location:

• behind the optic disc (blind spot) of retina

• protruding from the back of the sclera

function:

• sensory neuron that sends visual information to the brain

extraocular muscles

location:

• around the back of the eye

function:

• move the eye to gaze in different directions

aqueous humor

location:

• clear fluid in the front of the eye between cornea and iris

function:

• produced by ciliary body

• provides nutrients to the cornea and the lens