B10.5 - The Eye (Finished) Flashcards
What is the sclera?
It is the white outer layer of the eye. It is tough and strong to protect the eye
What is the cornea and what does it do?
It is the transparent area of the sclera at the front of the eye that refracts light into the eye.
What is the iris and what does it do?
Tge iris contains muscles that control the size of the pupil and therefore how much light enters the eye
What is the pupil?
The hole through which light enters the eye
What does the lens do?
It focuses the light onto the retina
What is the retina?
The area at the back of the eye that contains receptor cells sensitive to light
How does the retina cause us to see?
When the light-sensitive cells are stimulated, they send impulses to the brain through the optic nerve
What does the optic nerve do?
Carry impulses from receptors on the retina to the brain
How is the lens held in place?
By the suspensory ligaments
What do the ciliary muscles and suspensory ligaments do?
Control the shape of the lens
What happens when very bright light is shone into the eye?
1) Light receptors detect it
2) A reflex is triggered so:
3) The circular muscles in the iris contract
4) The radial muscles relax
5) Pupil has been made smaller so less light can enter the eye
When ___ receptors in the eye detect ___ light, the ___ muscles in the ___ contract and the ___ ones relax to make the pupil bigger.
Light, dim, radial, iris, circular
Why is there a reflex to make the pupil smaller under very bright light?
Very bright light can damage the retina so by making the pupil smaller less can enter
