The eye

Question 1

eyelid

Answer 1

fold of skin which covers the eye. It cleaning and protecting the eye

Question 2

pupil

Answer 2

hole in the middle of the iris. it allows light to enter the eye

Question 3

sclera

Answer 3

white part of the eye made of tough collagen fibres. it provides protection and support

Question 4

iris

Answer 4

ring of muscles around the pupil coloured which provides eye colour. controlling the amount of light entering the eye

Question 5

ciliary body

Answer 5

attached to the underside of the lens. producing aqueous humour and helping with focusing by altering the shape of lens

Question 6

cornea

Answer 6

the transparent covering on the eye. protecting the eye; helping converge bend and join light rays that enter the eye

Question 7

lens

Answer 7

transparent, flexible, and can change shape due to the ciliary muscles. focusing the light onto the retina and focusing on objects

Question 8

aqueous humour

Answer 8

found behind the cornea. helping to keep its round shape; providing nutrients to the cornea and lens

Question 9

media rectus muscles

Answer 9

found on the medial side of the eye. helping orientate the pupil towards the centre of the body

Question 10

choroid

Answer 10

a layer of blood vessels with a black pigment. nourishing the eye and absorbing light

Question 11

optic nerve

Answer 11

bundle of fibres. relaying information from the retina and fovea to the brain

Question 12

microscopy

Answer 12

light - a light microscope uses light and different lenses to magnify objects to allow the image to be seen through an eyepiece
electron-electron microscopes use electrons instead of light to produce detailed images with a high magnification

Question 13

magnification

Answer 13

image size/actual size

Question 14

staining a sample

Answer 14

chemical = gram = different types of bacteria = +red -violet
chemical = eosin = red blood cells and cell membrane pink
chemical = iodine = starch -blue black
chemical = methylene = nuclei and chromosomes - blue

Question 15

the vision process

Answer 15

Light rays are reflected and focused on the pupil as the enter through the cornea. Muscles in the iris contract or relax to control the amount of light passing through the pupil

Behind the pupil in the lens which reflects the light more so it is focused on the retina

The photoreceptors in the retina respond to the energy from the light and generate action potentials which are sent along the optic nerve to the brain for processing

Question 16

predators

Answer 16

binocular vision this creates a 3D image because of the overlap
eyes are on the front of the face narrow field of vision
have better depth perception than prey

Question 17

prey

Answer 17

monocular vision each eye works independently and only overlaps a small area
the eyes are positioned on the front of the head wider field of vision - good for detecting predators
poor depth perception

Question 18

photoreceptors in the eye

Answer 18

rods - seeing in low light
cons - seeing in a lot of light

Question 19

adaptations to see in the dark

Answer 19

tapetum lucidum - a layer that contains reflective pigment which helps animals see in low light

slit pupil as they are easier to contract than round

a much higher concentration of rod cells in the retina

much larger eyes which have wider pupils this allows them to capture more light

Question 20

vitreous humour

Answer 20

located behind the lens. giving the eyeball its shape

Question 21

lateral rectus muscle

Answer 21

found on the lateral side of the eye. helping orientate the pupil away from the centre of the body

Question 22

optic disc

Answer 22

a blind spot where there are on photoreceptors. where the optic nerves leave the eye

Question 23

tapetum lucidum

Answer 23

is layers of extra tissue behind the retina. reflects light back through the retina.
reflects light back through the retina
therefore increases light for photoreceptors

Question 24

fovea

Answer 24

spot located in the macula which has a high density of cone cells

• giving sharp central vision light is focused onto this spot by the lens