EYEBALL

Question 1

what is the outer layer of the eyeball wall called

Answer 1

fibrous tunic

Question 2

what is the function of the sclera

Answer 2

white if the eye, protects and gives shape

Question 3

what is the function of the cornea

Answer 3

refract rays of light and focus them onto the retina

Question 4

what is the middle later of the eye called

Answer 4

vascular tunic

Question 5

what us the function and structure of the choroid

Answer 5

dark brown membrane lining sclera. nourishes retina and absorbs light rays

Question 6

what is the structure and function of the ciliary body

Answer 6

extends from retina to base of iris. alters shape of lens for focusing. also secretes aqueous humour

Question 7

what is the function of the iris

Answer 7

alters size of pupil

Question 8

what is the structure and function of the pupil

Answer 8

controls the amount of light entering the eye

Question 9

what are the two muscles that are involved in constructing the pupil

Answer 9

circular and radial

Question 10

what is the inner layer of the eye

Answer 10

retina

Question 11

what is the function of the retina

Answer 11

lines posterior side of eyeball, involved in image formation and stores vitamin A

Question 12

what are the two layers of the retina

Answer 12

nervous layer and pigmented layer

Question 13

what are the three parts of the retina

Answer 13

macula lutea, fovea and optic disc

Question 14

what is the macula lutea

Answer 14

small area in the centre of the retina

Question 15

what is the fovea

Answer 15

in centre of macula, highest concentration of cones (photoreceptors)

Question 16

what is the optic disc

Answer 16

where ganglion neurons bend posteriorly to form optic nerve, (blind spot)

Question 17

what is the lens

Answer 17

flexible connective tissue, focuses light rays on the retina, attatched to sphincter muscles and divides the eye into posterior and anterior cavities

Question 18

what is the conjunctiva

Answer 18

thin mucous membrane lines eyelids and covers front surface of eyeball

Question 19

what is the function of conjunctiva

Answer 19

keeps eyeball moist

Question 20

what is the function of eyebrows and eyelashes

Answer 20

prevent debris and perspiration from entering the eye

Question 21

what does the aqueous humour do

Answer 21

maintains pressure on the eyeball, supplies lens and cornea with nutrients

Question 22

where is the anterior cavity

Answer 22

between the cornea and lens

Question 23

where is the posterior cavity

Answer 23

between the lens and the retina

Question 24

what is the posterior cavity

Answer 24

filled wot vitreous humour and prevents eyeball from collapsing, holds the retina against the choroid

Question 25

what are the two types of photoreceptors

Answer 25

rods and cones

Question 26

what are rods

Answer 26

dim light and peripheral vision receptors but don't provide sharp images

Question 27

what are cones

Answer 27

provides high clarity and colour vision

Question 28

what is the pigment in rods

Answer 28

rhodopsin. very sensitive to low intensities of light

Question 29

where is light absorbed by photopigments

Answer 29

in the dendrites of the rods and cones

Question 30

what causes colour blindness

Answer 30

absense or deficiency of one of the 3 types of cones (red, green or blue)

Question 31

how is the lens involved in refraction of light rays

Answer 31

can curve the lens to get more refraction of light