The Eye Flashcards
What does the eyelid do?
Protects the eye.
What is the job of the eyelashes?
Stops dust etc. Getting into the eye.
What is the job of the pupil
Controls the amount of light entering the eye.
What does the iris do?
Controls the size of the pupil.
What does the sclera do?
It is the tough layer that gives the eye protection.
What does the conjunctiva do?
A protective transparent covering that stops dust and dirt damaging the eye.
It also keeps the cornea moist.
What does the cornea do?
Transparent part of the sclera that allows light to enter. It is convex refracting (bending) the light as it enters the eye.
What is the function of the lens?
It is transparent, flexible disc behind the iris; that bends (refracts)light and focuses the light rays onto the retina.
What is the function of the retina?
Contains receptor cells that are sensitive to light.
What is the function of the fovea?
The central part of the retina contains a lot of light sensitive receptors and it particularly sensitive.
Function of optic nerve?
Contains sensory neurones that link the retina to the brain. Carries electrical impulses from the retina to the brain.
Aqueous humour function?
Maintains the correct pressure at the front part of the eye and it nourishes the cornea which has no blood vessels.
Vitreous humour function?
A jelly-like fluid which presses on the inner wall of the eyeball keeping it spherical.
Ciliary muscle function?
Circular muscles that contract and relax to control the shape of the lens.
Suspensory ligaments.
A series of fibres that connect the ciliary body of the eye with the lens holding it in place.
