Core Terminology 6: Eye Flashcards
Sense organ
an organ formed as a result of the concentration of receptors with the same function.
Photoreceptor
receptors in eye; that detect light stimuli.
Conjunctiva
mucous membrane covering the front of eye and eyelid.
Sclera
white, outer layer of eye that makes up the eyeball; maintains shape of eyeball.
Cornea
front transparent part of sclera; helps with refraction.
Iris
pigmented colour part of eye; controls amount of light that enters the eye.
Pupil
opening that allows light to enter.
Refraction
bending of light.
Choroid
dark pigmented vascular layer of eye (middle); provides eye with O2 & nutrients; also prevents reflection of light.
Ciliary body
front part of choroid
Suspensory ligaments
structures that holds lens in position.
Lens
elastic, transparent, biconvex structure that allows light through; changes shape to refract light onto retina.
Retina
inner layer of eye that contains the photoreceptors (rods + cones).
Rods
photoreceptor that reacts when light is low (poor); give rise to black and white vision.
Cones
photoreceptors that reacts to high light intensities; give rise to colour vision
Yellow spot
area in retina; contains the most photoreceptors.
Fovea centralis
area in middle of yellow spot where only cones occur; sharpest vision.
Blind spot
place where optic nerve leaves the eyeball; no rods or cones; no vision.
optic nerve
The nerve that carries impulses from the retina to the brain
Aqueous humour
watery fluid between lens and cornea
Vitreous humour
jelly-like substance filling the posterior cavity behind lens; maintains shape of eyeball.
Pupil mechanism
automatic (reflex) response to regulate amount of light that enters the eye.
Eye accommodation
process where the eye adapts/ adjust for the observation of near or far objects; by changing the shape of the lens.
Binocular vision
type of vision that provide a wider field of vision; creates a perception of depth (3D).
Myopia
short-sightedness; visual defect when a person can see close objects clearly but distant objects are out of focus; corrected with concave lenses.
Hypermetropia
far-sightedness; visual defect where a person can see far objects clearly, but not close objects; needs convex lenses to correct
Cataracts
clouding of lens; affecting vision; corrected with surgery.
Astigmatism
A disorder of the eye caused by the curvature of the lens or cornea being uneven, resulting in distorted images
Colour blindness
condition when certain colours cannot be distinguished
