2.86 describe the structure and function of the eye as a receptor.
Sclera - is the tough outer coat, which is the visible white part of the eye.
Cornea - found at the front of the eye - it is convex + transparent - it lets light into the eye.
Iris - found behind the cornea - it is a colored ring of tissue and it is pigmented (decided the color of your eye) - its muscles contract and relax to alter the size of its pupil (controlling how much light enters the eye)
Pupil - found in the middle of the iris hole - it lets the light through - it is black because there is no light escaping from the inside of the eye.
Choroid - is a dark layer found underneath the sclera - it is dark because it contains many pigment cells + blood vessels - the pigment stops light being reflected around inside the eye.
Retina - is the innermost layer (found underneath the Choroid - this is where light energy is transduces into electrical energy of nerve impulses - the retina contains 2 types of photo-receptor cells,
a) Rods - sensitive to dim light + black and white
b) Cones - sensitive to colour
Fovea - found in the middle of the retina - is a small area concentrated with Cones ( cones give sharper images than rods)
Optic nerve - is a bundle of sensory nerves found at the back of the eye - they carry impulses from the eye to the brain.
Blind spot - located where the optic nerve leaves the eye at the back of the Retina - an image cannot be formed here because there are no Rods or Cones here.