Eye

Question 1

What is the cornea and where is it located?

Answer 1

It is the bulged part of the sclera. It is tough and transparent.
It is the outer-most part of the eye apart from the conjunctiva.

Question 2

What is the function of the cornea?

Answer 2

Refracts light and bends it as it enters the eye

Question 3

What is the iris and where is it located?

Answer 3

A pigmented section, so that light can’t pass through it.

It has the pupil in the middle of it, and the lens behind the pupil.

Question 4

What is the function of the iris?

Answer 4

Its muscles contract and relax to change the size of the pupil.
This controls the amount of light entering the pupil.

Question 5

What is the lens and where was it located?

Answer 5

It is a transparent, flexible disc behind the iris.

It is attached to the ciliary muscles by the suspensory ligaments.

Question 6

What is the function of the lens?

Answer 6

It focuses light onto the retina

Question 7

What is the retina and where is it located?

Answer 7

It is the lining of the back of the eye, which contains two types of photoreceptor cells, rods (black and white) and cones (colour)

Question 8

What is the function of the retina?

Answer 8

It contains light receptors

Question 9

What is the optic nerve and where is it located?

Answer 9

It is a bundle of sensory neurones at the back of the eye

Question 10

What is the function of the optic nerve?

Answer 10

It carries impulses from the eye to the brain

Question 11

What is the fovea and where is it located?

Answer 11

It is a small area in the middle of the retina that contains many more cones than rods

Question 12

What is Myopia?

Answer 12

Short-sightedness

Question 13

What is Hypermetropia?

Answer 13

Long-sightedness

Question 14

How is Mytopia caused?

Answer 14

When the lens focuses the sharpest image in front of the retina (short-sight)

Question 15

How is Hypermetropia caused?

Answer 15

When the lens focuses the sharpest image behind the retina (long-sight)

Question 16

What is the aqueous humour and what does it do?

Answer 16

It is a transparent watery fluid located in the front of the eye (between the lens and the cornea)
It maintains the shape of the eyeball

Question 17

What is the vitreous humour and what does it do?

Answer 17

It is the transparent jelly which fills the large space behind the lens.
It holds the lens and retina in place and it helps bend light

Question 18

What is the ciliary muscle and what does it do?

Answer 18

It is a ring of muscle which is attached to the lens by the suspensory ligaments.
It changes the thickness of the lens so light rays can be focused on the retina.

Question 19

What happens when the ciliary muscle contracts?

Answer 19

The suspensory ligaments slacken and the lens thickens

Question 20

What happens when the ciliary muscle relaxes?

Answer 20

The suspensory ligaments pull on the lens and the lens becomes thinner

Question 21

What is the choroid layer?

Answer 21

It is the thin black middle layer which contains the main blood vessels and blood supply to the eye.
Its black pigment prevents reflection of light within the eyeball.

Question 22

What is the sclera?

Answer 22

It is the tough, white outer layer which protects the delicate parts in the eye

Question 23

What is the function of the suspensory ligaments?

Answer 23

They hold the lens in place and change the shape of the lens in conjunction with the ciliary muscle

Question 24

Where is the blind spot?

Answer 24

The point at which the optic nerve leaves the eye

Question 25

What happens to the eye when exposed to bright light?

Answer 25

The radial muscles of the iris relax
The circular muscles contract
Less light enters the eye through the contracted (smaller) pupil

Question 26

What happens to the eye when exposed to less/dim light?

Answer 26

The radial muscles of the iris contract
The circular muscles relax
More light enters the eye through the dilated (larger) pupil