The Eye Flashcards
How does the brain receive messages from the eye?
By impulses from the eye along the optic nerve and interprets the impulses to form a picture
What is the eye?
Sense organ for detecting light
How does the eye work?
Controlled amount of light enters (iris controls this)
Light focused on a light sensitive layer (retina)
Image created by when brain interprets the impulses it recieves
What does the cornea do?
Focuses most of the light, made of transparent tissue
What is the pupil?
Gap between iris muscles
What do the suspensory ligaments do?
Grip onto the lens
What does the ciliary muscle and body do?
Contracts to change the shape of the lens to focus the light
What function is the sclera?
Protects eye
What does the retina do?
Consists of light sensitive neurones, RODS and CONES
Cones sensitive to red green and blue
Rods sensitive to low levels of light
How is the amount of light entered controlled?
By the size of the pupil controlled by iris
Bright light - pupil smaller to stop light, circular muscles contract, radial muscles relax
Dim light - pupil bigger for more light, circus or muscles relax and radial muscles contract
Describe iris reflex…
Stimulus - light intensity Retina - receptor Sensory neurones - in optic nerve Brain Nerve impulses - along motor neurones Iris muscles - circular/radial Response - change in size of pupil
