Human Eye

Question 1

What is the conjunctiva

Answer 1

Conjunctiva - a clear membrane that covers the white of the eye and the inside of the eyelids; it lubricates the eye and provides protection from external irritants

Question 2

What is the cornea

Answer 2

Cornea - transparent, curved layer at the front of the eye that refracts light as it enters the eye

Question 3

What is the sclera

Answer 3

Sclera - the strong outer wall of the eyeball that helps to keep the eye in shape and provides a place of attachment for the muscles that move the eye

Question 4

What is the pupil

Answer 4

Pupil - circular opening in the centre of the iris that allows light to enter the eye

Question 5

What is the iris

Answer 5

Iris - controls how much light enters the pupil

Question 6

What is the lens

Answer 6

Lens - transparent disc that can change shape to focus light onto the retina

Question 7

What is the ciliary muscle

Answer 7

Ciliary muscle - a ring of muscle that contracts and relaxes to change the shape of the lens

Question 8

What is the suspensory ligaments

Answer 8

Suspensory ligaments - ligaments that connect the ciliary muscle to the lens

Question 9

What is a retina

Answer 9

Retina - contains receptor cells sensitive to light

Question 10

What is the optic nerve

Answer 10

Optic nerve - carries impulses between the eye and the brain

Question 11

What is the blind spot

Answer 11

Blind spot - the point at which the optic nerve leaves the eye, where there are no light receptor cells

Question 12

What happens to the eyes when an object is close up

Answer 12

When an object is close up:
The ciliary muscles contract (the ring of muscle decreases in diameter)
This causes the suspensory ligaments to loosen
This stops the suspensory ligaments from pulling on the lens, which allows the lens to become thicker
Light is refracted more

Question 13

What happens to the eyes when the object is far away

Answer 13

When an object is far away:
The ciliary muscles relax (the ring of muscle increases in diameter)
This causes the suspensory ligaments to tighten
The suspensory ligaments pull on the lens, causing it to become thinner
Light is refracted less