B14. Coordination & Response

Question 1

Cornea

Answer 1

Refracts light

Question 2

Iris

Answer 2

Controls how much light enters pupil

Question 3

Lens

Answer 3

Focuses light onto retina

Question 4

Retina

Answer 4

Contains light receptors, some sensitive to light of different colours

Question 5

Optic nerve

Answer 5

Carries impulses to brain

Question 6

Blind spot

Answer 6

The area where the optic nerve leaves the retina; it has no receptor cells

Question 7

Fovea

Answer 7

The central part of the retina where light is focused when you look straight at an object

Question 8

Ciliary muscle

Answer 8

Controls the thickness of eye lens

Question 9

Suspensory ligament

Answer 9

Holds the eye lens

Question 10

How does the eye function to produce a focused image?

Answer 10

Light passes through cornea and then into the pupil. The eye lens focuses light onto the retina, specifically the fovea.

Question 11

Pupil reflex - in bright light

Answer 11

1. Circular muscles contract
2. Radial muscles relax
3. Pupil constricts, less light enters

Question 12

Pupil reflex - in dim light

Answer 12

1. Circular muscles relax
2. Radial muscles contract
3. Pupil dilates, more light enters

Question 13

Accommodation process - focusing on near objects

Answer 13

1. Ciliary muscles contract
2. Suspensory ligaments relax/loosen
3. Eye lens gets thicker (more convex), bends light rays more

Question 14

Accommodation process - focusing on distant objects

Answer 14

1. Ciliary muscles relax
2. Suspensory ligaments become taut/tighten
3. Eye lens gets thinner (less convex), bends light rays less

Question 15

Negative feedback

Answer 15

A mechanism that brings about actions to bring values of the internal environment back to normal

Question 16

Role of auxin in controlling shoot growth

Answer 16

1. Auxin is made in shoot tip
2. Auxin spreads through the plant from the shoot tip
3. Auxin is unequally distributed in response to light and gravity
4. Auxin stimulates cell elongation