The Eye Flashcards
Components of the eye
-Cornea
-Iris
-Pupil
-Retina
-Optic nerve
-Fovea
-Lens
Role of the iris
Controls the diameter of the pupil
What allows the cornea to refract light
-Transparent so light can go through
-No blood vessels
Role of the lens
Also refracts light but can change it’s shape so light is perfectly focused onto the fovea.
Role of the retina
-Made up of 2 different types of receptor cells
-Cone cells to allow us to see colour
-Rod cells to allow us to see light
Info about Cone cells
They don’t work well in dim light
Info about Rod cells
They are more sensitive to light but only allow us to see black and white
this is why you can’t see colours when it’s dark as only rod cells working
Info about fovea
Only contains cone cells for colour
Role of the optic nerve
-Takes all of the impulses generated by receptor cells and transmits them to the brain
What happens in the iris reflex?
The pupil becomes constricted or dilated to allow more/less light in
What muscles is the iris made up of?
-Circular muscles
-Radial muscles
What happens to iris when there is bright light
-Circular muscles contract and radial muscles relax to allow less light in to the retina
What happens to iris when there is dim light
-Radial muscles contract and circular muscles relax to allow more light in to retina.
What is accomodation
A reflex that changes the refractive power of the lens.
What parts of the eye are involved in accomodation?
-Lens
-Cornea
-Suspensory ligaments
-Ciliary muscles
