Eye

Question 1

parts of the eye that alters the direction of the light rays?

Answer 1

Lens/ Cornea/ aqueous humour/ vitreous humour/ conjunctiva

Question 2

parts of the eye where light ray forms an image?

Answer 2

retina/ fovea

Question 3

Outline how humans are able to see in colour?

Answer 3

cones are light sensitive
3 different types of cones
respond to, different wavelengths of red, green and blue light
convert light into electrical impulses
passed along the optic nerve
brain interprets impulses in terms of, colours /red, green and blue ;

Question 4

Part of tissue with cones but no rods?

Answer 4

Fovea

Question 5

Part of tissue with no rods and no cones?

Answer 5

Blind spot

Question 6

distribution of rods and the type of light detected?

Answer 6

to shades of grey
dim light/black and white/
low light intensity;

spread over (retina);
more concentrated on
margins

Question 7

distribution of cones and the type of light detected?

Answer 7

colour/bright light/
high light intensity/day(light);

in fovea/yellow spot;

Question 8

How do rods and cones function?

Answer 8

light is absorbed (by a pigment) ;
rods detect low light (intensity) ;
do not detect colour ;
provide night vision.
cones detect high light (intensity) ;
cones detect colour ;
three different types of cone ;
convert light into (electrical) impulses ;
impulses sent to brain ;
via, optic nerve ;

Question 9

How do rods and cones differ from each other?

Question 10

Why are shapes visible in dark but not colours?

Answer 10

Light absorbed by pigment.
Rods detect low light intensity. Not colour. Provide night vision.
Cones detect high light intensity. Yes colour
3 different types of cones
Light is converted into electrical impulse
Impulse is sent to the brain via the optic nerve.

Question 11

the correct
order that the light passes through the eye?

Answer 11

cornea
aqueous humour
pupil
lens
vitreous humour
retina

Question 12

Changes in eye to focus on a distant object?

Answer 12

ciliary muscles relax
suspensory ligament(s) becomes taut
lens is made thinner
less convex
lens becomes flat
less refraction of light

Question 13

Changes in eye to focus on a near object?

Answer 13

ciliary muscles contract
suspensory ligaments slack
lens is made thicker
more convex
lens becomes round
more refraction of light

Question 14

Changes in eye in bright light?

Question 15

Changes in eye in dim light?

Answer 15

pupil small
iris circular muscle contract
radial muscle relax

Question 16

Role of ciliary muscles?

Question 17

Role of iris circular muscles?

Answer 17

controls the amount of light entering the eye

Question 18

How is an image formed on the retina?

Question 19

Type of lens used for old people?

Answer 19

convex
will increase the refraction of light
converge them so they fall on the retina
clear image formed