B3.1.3- the eye

what are the features that make up the eye- A,B,C,D,E,F,H,L 7

E. lens- focuses light onto retina

B. suspensory ligaments- connects ciliary muscle to lens

A. ciliary muscle- alters shape of lens

C. iris- alters pupil size by contracting or relaxing

D. pupil- allows light to enter eye

H. optic nerve

F. cornea- protects eye

L. retina- light receptor

what is the process of you creating an image to your eyes 3

1. light comes through pupil

2. it then goes into the retina and produces a nerve impulse

3. this goes down the optic nerve to the brain where it produces a visual image.

what happens when your ciliary muscle CONTRACTS

your lens becomes fatter and MORE convex.

what happens when the ciliary muscle RELAXES

your lens becomes thinner and LESS convex

when your at a short sight where does the light go

in front of the retina

what do you need when you are short sighted and how does it help

a CONCAVE lens and it bends light outwards

when your sight is long where does the light go

behind the retina

what do you need when you are long sighted and how does it help

you need a convex lens which bends light inwards

what are the retinas 2 type of photoreceptors cells

Rod cells and Cone cells

what do Rod cells do

they respond to light and allow you to see in low light levels. they are NOT responsive to different colours

what do cone cells do

they respond to different colours. different Cone cells respond to red, blue, and green light