Eye

Question 1

draw a diagram of the internal structure of an eye

Answer 1

see diagram in manual

Question 2

structure of the sclera

Answer 2

• outer layer of the eye which is opaque

- forms cornea at the front of the eye

Question 3

function of the sclera

Answer 3

-protection and gives shape to the eyeball

Question 4

structure of the choroid

Answer 4

-dark black middle layer with melanin

Question 5

function of the choroid

Answer 5

prevents internal reflection

-i.e. absorbs any light rays that may pass beyond the retina

Question 6

structure of the retina

Answer 6

-innermost layer of the eye with rods and cones which are photoreceptors

Question 7

function of the retina

Answer 7

converts light into nerve impulses so an image forms on the retina

-basically generates impulses

Question 8

structure of the fovea

Answer 8

-part of the retina with cones only

Question 9

function of the fovea

Answer 9

-gives detailed coloured vision in bright light

Question 10

structure of photoreceptors

Answer 10

• they are sensory cells sensitive to light
• called rods and cones
• rods contain the pigment rhodospin which need vitamin A to manufacture

Question 11

function of photoreceptors

Answer 11

• rods provide vision in dim light, but detail is in black, white and grey
• cones give coloured vision in bright light

Question 12

structure of cornea

Answer 12

-is the transparent front of the eye with a curved surface so it can focus light rays

Question 13

function of the cornea

Answer 13

allows light to enter the eye and bends it toward the retina

Question 14

structure of the aqueous humour

Answer 14

-clear liquid with salt

Question 15

function of the aqueous humour

Answer 15

supplies nutrients and oxygen to the cornea and maintains the shape of the cornea

Question 16

structure of the vitreous humour

Answer 16

clear and gel like

Question 17

function of the vitreous humour

Answer 17

maintains the correct shape of the eyeball

Question 18

structure of the pupil

Answer 18

the pupil is the central opening of the iris

Question 19

function of the pupil

Answer 19

is to allow light to enter the eye:
-dilates (widens) is dim light to allow more light to enter the eye

-constricts (gets narrower again) so less light enters and avoids the dazzling effect

Question 20

structure of the iris

Answer 20

-coloured sheath of muscle with melanin

Question 21

what does the iris determine

Answer 21

the iris determines the diameter of the pupil

Question 22

what is the function of the iris

Answer 22

> iris controls the amount of light entering the eye as follows

• iris contracts
• in response to changing light intensity
• therefore changing the size of the pupil so more or less light enters the eye

Question 23

what is the structure of the lens

Answer 23

lens is transparent with a curved surface

biconcave in shape

Question 24

function of the lens

Answer 24

lens focuses light on the retina and carries out fine adjustments to produce sharp image

Question 25

structure of the suspensory ligaments

Answer 25

fibres which connect the the ciliary body to the lens

Question 26

function of the suspensory ligaments

Answer 26

the suspensory ligaments holds the lens in position and are involved in changing the shape of the lens

Question 27

structure of the ciliary body

Answer 27

the ciliary body is a ring of choroid tissue which contains the ciliary muscle

Question 28

function of the ciliary body

Answer 28

the ciliary body secretes the fluid that forms the aqueous humour

Question 29

function of the ciliary body

Answer 29

the ciliary body secretes the fluid which forms the aqueous humour

Question 30

function of the ciliary muscle

Answer 30

the ciliary muscle controls the curvature and focusing strength of the lens

Question 31

structure of the blind spot

Answer 31

part of the retina

Question 32

function of the blind spot

Answer 32

does not generate a visual response as theres no rods and cones here

Question 33

structure of the optic nerve

Answer 33

bundles of nerve fibres

Question 34

function of the optic nerve

Answer 34

the optic nerve carries impulses to the cerebrum of the brain