EYEBALL Flashcards

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1
Q

what is the outer layer of the eyeball wall called

A

fibrous tunic

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2
Q

what is the function of the sclera

A

white if the eye, protects and gives shape

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3
Q

what is the function of the cornea

A

refract rays of light and focus them onto the retina

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4
Q

what is the middle later of the eye called

A

vascular tunic

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5
Q

what us the function and structure of the choroid

A

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

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6
Q

what is the structure and function of the ciliary body

A

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

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7
Q

what is the function of the iris

A

alters size of pupil

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8
Q

what is the structure and function of the pupil

A

controls the amount of light entering the eye

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9
Q

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

A

circular and radial

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10
Q

what is the inner layer of the eye

A

retina

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11
Q

what is the function of the retina

A

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

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12
Q

what are the two layers of the retina

A

nervous layer and pigmented layer

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13
Q

what are the three parts of the retina

A

macula lutea, fovea and optic disc

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14
Q

what is the macula lutea

A

small area in the centre of the retina

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15
Q

what is the fovea

A

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

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16
Q

what is the optic disc

A

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

17
Q

what is the lens

A

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

18
Q

what is the conjunctiva

A

thin mucous membrane lines eyelids and covers front surface of eyeball

19
Q

what is the function of conjunctiva

A

keeps eyeball moist

20
Q

what is the function of eyebrows and eyelashes

A

prevent debris and perspiration from entering the eye

21
Q

what does the aqueous humour do

A

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

22
Q

where is the anterior cavity

A

between the cornea and lens

23
Q

where is the posterior cavity

A

between the lens and the retina

24
Q

what is the posterior cavity

A

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

25
Q

what are the two types of photoreceptors

A

rods and cones

26
Q

what are rods

A

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

27
Q

what are cones

A

provides high clarity and colour vision

28
Q

what is the pigment in rods

A

rhodopsin. very sensitive to low intensities of light

29
Q

where is light absorbed by photopigments

A

in the dendrites of the rods and cones

30
Q

what causes colour blindness

A

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

31
Q

how is the lens involved in refraction of light rays

A

can curve the lens to get more refraction of light