The eye Flashcards
How is dirt stopped from landing on the surface of your eye?
Eyelids, eylashes and eyebrows protect it
Function of retina?
Contains light receptors , some sensitive to light of different colours
What is the function of the optic nerve?
Carries impulses to the brain
What are rod cells?
Receptor cells that are sensitive to dim light but do not respond to colour
What are cone cells?
Receptor cells that respond to colour(red, blue, green)but only when the light is quite bright
What is the fovea?
Has lots of cones.
The part of the eye where receptor cells are closest together.
It is the part of the retina where light is focused when you look at an object
How does the fovea produce a sharp coloured image?
It has mostly cones packed tightly together to produce a sharp coloured image.
What is the blind spot?
The place where the optic nerve leaves the retina. There are no receptor cells here
Function of the iris?
Controls how much light enters the pupil
What is the pupil?
A gap in the middle of the iris. Lets light into the eye
What adjusts pupil size?
Radial and circular muscles in the iris
What happens when the light is too bright?
Radial muscles relax , circular muscles contract. Pupil constricts
What happens when there is too little light?
Radial muscles contract , circular muscles relax , pupils dilate
Sense organs
Groups of receptor cells responding responding to specific stimuli : light, sound , touch, temperature and chemicals
