The Eye

Question 1

Cornea

Answer 1

Front part of the sclera which is clear, helps to refract and focus light

Question 2

Suspensory ligament

Answer 2

Ligaments connecting the ciliary muscle and the lens hold lens in place

Question 3

In bright light the pupil…

Answer 3

Constricts. Circular muscles contract, radial muscles relax. Prevents too much light entering eye and damaging it.

Question 4

The eye is a

Answer 4

Sense organ

Question 5

Fovea (yellow spot)

Answer 5

Area dense with cones. Produces a detailed image

Question 7

Ciliary muscle

Answer 7

Ring of muscle connected to lens via suspensory ligaments. Helps change the shape of the lens

Question 8

Optic nerve

Answer 8

Part of CNS. Transmits nerve impulses from retina to brain to create image

Question 9

Choroid

Answer 9

Black pigment which absorbs light. Prevents light reflecting inside the eye

Question 10

Rod

Answer 10

Photoreceptor in retina used for dim light vision, only shows black and white. Detects intensity of light.

Question 11

In low light the pupil

Answer 11

Dilates. The circular muscles relax and the radial muscles contract

Question 12

Cone

Answer 12

Photoreceptor in retina. Detects colour. Do not work in low light.

Question 13

There are 3 types of cone cell in the retina. They detect which colours of light?

Answer 13

Red, blue, green

Question 14

2 types of receptor cell

Answer 14

Rods and cones

Question 15

Retina

Answer 15

Light sensitive inner layer of eye which contains photoreceptors

Question 17

Retina

Answer 17

Internal lining at back of eye contains rods and cones which respond to light.

Question 18

Why is the pupil black?

Answer 18

Because there is no light escaping from the inside of the eye

Question 19

What stimulus does the eye detect?

Answer 19

Light

Question 20

Receptor cells in the eye where are they and what do they di

Answer 20

-at the back of the eye in the retina
-sensitive to light and transmit impulses to the CNS
When light falls on these cells they send off nervous impulses

Question 21

2 types of receptor cell in eye

Answer 21

Cones - sensitive in high light intensities and allow us to see in colour (in the fovea)
Rods - sensitive in low light intensities and produce images in black and white

Question 22

Sclera

Answer 22

Tough, white outing coating which protects the eye

Question 23

Iris

Answer 23

Flexible disc of tissue which can change its shape in order to let more light into the pupil
Controls light entering eye

Question 24

Pupil

Answer 24

Hole in centre of iris which lets in light to rest of eye

Question 25

Lens

Answer 25

A transparent structure which is flexible and can change its shape in order to focus on an image

Question 26

Suspensory ligament

Answer 26

A ring of fibres which holds the lens in place

Question 27

Ciliary muscle

Answer 27

``` Ring of muscle connected to lens via suspensory ligament Controls accommodation (focusing) ```

Question 28

Accommodation

Answer 28

The reflex that makes the eye focus on an object by changing the shape of its lens

Question 29

How do we see things?

Answer 29

Light reflected from an object is refracted by the cornea and the lens forming an upside down image on the retina

Question 30

Why can't we see colours so well in the dark

Answer 30

When there is little light, the cones do not work so we find it difficult to tell what colour things are

Question 31

What is the conjunctiva

Answer 31

Layer covering the cornea and sclera that helps to lubricate the eye