The Eye

Question 1

What type of organ is the eye?

Answer 1

sense organ

Question 2

Lable the diagram

Answer 2

1. cilary muscle
2. suspensory ligament
3. retina
4. fovea
5. optic nerve
6. iris
7. cornea
8. conjuctiva
9. pupil
10. lens

Question 3

What do the ciliary muscles do?

Answer 3

change the thickness of the lens when focusing

Question 4

What is the blind spot?

Answer 4

where blood vesels and nerves join the eyeball

Question 5

What is the optic nerve?

Answer 5

receives nerve impulses from the retina and sends them to the brain

Question 6

What is the retina?

Answer 6

contains light-sensitive cells: rods for dim light, cones for colour.

It sends impulses to the brain

Question 7

What is the cornea?

Answer 7

a transparent window in the front of the eye - it refracts light

Question 8

What are suspensory ligaments?

Answer 8

ligaments that hold the lens in place

Question 9

What is the lens?

Answer 9

helps to focus light on the retina

held in place by the suspensory ligament and ciliary muscle

Question 10

What is the pupil?

Answer 10

A hole that allows light through

Question 11

What is the muscular iris?

Answer 11

controls how much light enters the eye and alters teh size of the pupil

Question 12

What happens to the pupil in bright light?

Answer 12

• circular muscles contract
• radial muscles relax
• iris closes and makes the pupil smaller

Question 13

What happens to the pupil in dim light?

Answer 13

• Radial muscles contract
• circular muscles relax
• iris opens and pupil gets bigger

Question 14

What is it called when light passes through the cornea and lens and an object is focused on the retina?

Answer 14

accommodation

Question 15

What happens when the eye focuses on near objects?

Answer 15

• ciliary muscles contract
• suspensory muscles slacken
• lens shape is fat and round

Question 16

What happens when the eye focuses on far objects?

Answer 16

• ciliary muscles relax
• suspensory muscles contract
• lens shape is thin and flat

Question 17

What type of vision do humans have?

Answer 17

Binocular

Question 18

What advantages are there to having binocular vision?

Answer 18

• able to judge distance
• able to judge depth
• eyes are forward facing (like most predators)

Question 19

Name something that has monocular vision

Answer 19

• horses
• cows
• prey animals

Question 20

What advantages are there to having monocular vision - eyes on the side of the head?

Answer 20

• have a wider field of vision

Question 21

What is short sightedness?

Answer 21

• light is focused too far in front of the retina
• can see near objects but not far

Question 22

What is long-sightedness?

Answer 22

• eyeball is too short
• distant objects can be seen but not close ones

Question 23

What causes red/green colour blindness?

Answer 23

• inherited condition
• affects more males than females
• cones do not function properly