Eye Flashcards
What is the function of the cornea?
It refracts light and protects the eye
What is the function of the iris?
To control how much light enters the pupil
What is the function of the lens?
Focuses light onto the retina
What is the function of the optic nerve?
A bundle of sensory neutrons that carry impulses to the brain
What is the function of the retina?
Layers of tissue that contain photoreceptor cells called rods and cones
What is the function of the fovea
Area of the retina with the highest concentration of cone cells that provides sharp vision
What is the function of the aqueous humour
Maintains pressure in the eye and nourishes cornea
What is the function of the vitreous humour
Maintains the shape of the eye and attaches to the retina
What is the function of the ciliary muscles ?
Help change the shape of the lens in accommodation
What is the function of the sclera?
Tough outer layer that extraoculular muscles can attach to
What is the function of the pupil
Hole in centre of eye to let light in
What light do rods work in
Dim light but they can only see black and white
What light can comes work in
Bright light
What are the three types of cone cells
Red green blue
How do we see lol
The image is refracted by the cornea and then the lense
How does the iris change the shape of the pupil?
Using circular and radial muscles
Why does the iris change the shape of the pupil
To control the amount of light entering the eye
What do the circular muscles do in bright light ?
Contract making the pupils constrict
What do the radial muscles do in bright light ?
Relax so the pupils constrict
What do the circular muscles do in dim light?
Relax so the pupils dilate
What do the radial muscles do in dim light ?
Contract so the pupils dilate
How do eyes focus
By accommodation
- changing shape of lens
What controls accommodation,
Ciliary muscles and suspensory ligaments
What happens when focusing on a distant object?
Ciliary muscles relax
Susp ligs tighten
Lens is pulled thin
What happens when focusing on a close object?
Ciliary muscles contract
Susp ligs slacken
Lens becomes fatter
