Eye parts Flashcards
What is the eye
The eye is a sense organ that contains receptor cells that are sensitive to light and colour
What is the sclera
It is a collagen fibrous layer
Protects the eye ball gives it its shape
Chlorid
Black pigmented layer
Absorbs light energy, preventing any reflection of light inside the eye so multiple image formation is prevented
Has blood vessels, which supplies oxygen and glucose for the respiration of photoreceptors
Conjunctiva
Protective layer
Transparent
Retina
Consists of photoreceptors (rod cells and cone cells)
Changes light into an electrical impulse
Has 2 special spots
Fovea- only cone cells with highest visual accuracy
Blindspot- no rod and cone cells and nothing can be seen if eye fells
Photoreceptors
They are transducers as they convert light to electrical impulse
Rod cells
work in dim light
They cannot distinguish between colours so image is black and white
Cone cells
Work in bright light
3 types which respond to different wavelength/colours- red, green and blue. As a result of this we can see all the colours of visible light.
Cone gives a sharper image than rods
Ciliary muscles and suspensory ligaments
Contraction and relaxation of ciliary muscle controls shape of lens
Suspensory ligaments attach lens to ciliary muscle
Lens
Made out of protein fibres in an elastic capsule
Transparent to light
Focus light on retina by refraction of light
Cornea
Transparent lens that refracts light as it enters the eye
Aqueous and vitreous humor
Fluid in the eye that is transparent to light
Useful to maintain the shape of the eye
Tear glands
Secrete tears
Tears are made out of water, sodium chloride, Lysosomes
Tear glands produce and secrete tears which passes across the eyeball and drain to the back of the nose
