The eye (coordination and control) * Flashcards
What is the function of the lens?
it focuses light onto the retina - round when the object is near to the eye and flat when the object is far away
What is the function of the cornea?
it refracts around 75% of the light entering the eye
What is the function of the iris?
it controls the amount of light entering the eye
The iris - fill the gaps :
- under bright conditions, the _______ muscles of the iris ______
- this ______ the size of the pupil
- under dim conditions, the _____ muscles of the iris ____
- this ________ the size of the pupil (dilates)
- under bright conditions, the circular muscles of the iris contract
- this reduces the size of the pupil
- under dim conditions, the radial muscles of the iris relax
- this increases the size of the pupil (dilates)
What is the function of the ciliary muscle?
it controls the shape of the lens - when it contracts the lens is thicker, when it relaxes the lens is thinner
What is the function of the vitreous humour?
a gel like fluid that maintains the shape of the eye
What is the function of the retina?
where light is detected - full of rods and cone cells
What is the function of the pupil?
the whole in the middle of your eye where light enters
What is the function of the conjunctiva?
a barrier between the eye and the outside environment
it contains lysozymes to kill microorganisms that enter the eye
What is the function of the optic nerve?
it carries impulses from the rod and cone cells to the brain
What causes short sightedness?
the lens bends light to much or the eyeball is too long
What causes long sightedness?
the lens doesn’t bend light enough or the eyeball is too short
How can short sightedness be corrected?
with a concave lens
