The transparentpart of the sclera at the front of the eye.
Let's light in and bends it towards the retina
Describe the Conjunctiva and its function
Transparentmembrane protecting the cornea
Describe the Choroid and its functions
contains the bloodcapillaries to nourish the eye and melanin (black pigment) to absorb light (no internal reflection of light)
Describe the retina and its function
the innermost layer containing the light receptors (rods and cones)
Describe the rods
contain rhodopsin (vitamin A required to form it)
detect black and white
work in dim light
found all over retina
Describe the cones
Have 3 pigments that detect blue, red and green
detect color
found mostly in the fovea
work in bright light
Blindspot
the area where the optic nerve leaves the eyeball
contains no visual receptors
Fovea (yellow spot)
opposite the centreof the pupil
contains conesonly. Regions of sharpest vision, most images are formed here
Optic nerve
Carries impulses from the retina to the brain.
Iris
coloured part of the eye. Controls size of pupil and amount of light entering the eye (reflex action).
Its circular muscle contract to narrow the pupil in bright light to reduce the amount of light and its radical muscles contact to widen the pupil in dim light enters the eye
Pupil
opening in the iris through which light enters.
Lens
biconvex, transparent and elastic, changes shape to focus light on to the retina. Contains a clear protein which can become cloudy (cataracts).
Ciliary muscle
changes shape of the lens
Suspensory ligament
Attaches the ciliary body to the lens.
Aqueous humor
A watery liquid between cornea and lens, made in ciliary body-maintains eye shape; nourishes cornea and lens (these don't have their own blood supply) and helps to refract light.
Vitreous humor
A jelly-like substance between lens retina, gives shape to the eye
Accommodation
changing the shape of the lens to focus near and distant objects