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BIOLOGY > The Human Eye > Flashcards

The Human Eye Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

describe the conjunctiva

A

mucous membrane, covering the front of eye 1/5

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2
Q

specifically state the functions of the conjunctiva

A
  1. produces lubrication mucous that prevents drying out.

2. pain receptors that reflexively cause eyelids to close from foreign objects

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3
Q

describe the sclera

A

tough, white inelastic and made of connective tissue and covers posterior 4/5

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4
Q

specifically state the functions of the sclera

A
  1. provides attachment for 6 extrinsic eye muscles,

2. it is inelastic so it keeps the posture right

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5
Q

describe the cornea

A

continuation of sclera in front of eye, transparent, curved to cause refraction

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6
Q

specifically state the functions of the cornea

A

protection of the eye, causes set converging refraction

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7
Q

name the structures of the outer fibrous coat

A

conjunctiva
cornea
sclera

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8
Q

describe the choroid

A

thin and dark straight below the SCELRA filled with blood vessels

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9
Q

functions of the choroid

A

absorbs light to prevent reflection which can cause blurriness and supply eye with nourishments of oxygen and food to retina cells

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10
Q

describe the ciliary body

A

muscular extension of CHOROID used to change the shape of the lens

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11
Q

function of the ciliary

A

controlling bulge of lens during accommodation

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12
Q

describe the iris

A

coloured extension of CHOROID used to adjust the amount of light entering the eye or how large the pupil is

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13
Q

definition of annular

A

ring

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14
Q

state the two involuntary muscles

A
  1. circular

2. radial

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15
Q

why are circular and radial muscles antagonistic

A

because the counteract each other one contracts while the other relaxes

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16
Q

describe the radial muscles

A

straight
contract (pull away) there’s a big pupil in DIM LIGHT
relax (longer) constricted pupil in BRIGHT LIGHT

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17
Q

describe the circular muscles

A

contract (move to the middle) there’s a smaller pupil in BRIGHT LIGHT
relax (they go away leaving a hole) dilated pupil in DIM LIGHT

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18
Q

describe the pupil

A

it is not a structure it is in fact just an opening and looks black because of the dark cavity, it is the point where light enters

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19
Q

how does brown affect the chances of iris colour

A

since brown is such a dominant colour, if you were to get a blue colour that means that there is no presence of brown pigment

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20
Q

function of the iris

A

controls the amount of light entering the eye by pupillary mechanism with the circular and radial muscles

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21
Q

name the structures of the middle vascular layer

A

choroid
iris
ciliary body

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22
Q

what is the pigment layer

A

it is a dark layer in the retina that absorbs light

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23
Q

describe the nervous layer

A

area of the retina that contains the photoreceptors, rods, and cones

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24
Q

function of photoreceptors

A

converts light stimulus into nerve impulses

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25
Q

describe rod cells

A

found in the PERIPHERAL of retina (edge)

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26
Q

function of the rods

A

give peripheral vision and respond to low light/night viand black and white

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27
Q

describe cone cells

A

responds to bright light and colour vision

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28
Q

function of the cones

A

detect colour , sharper and clearer vision

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29
Q

describe the neural layer

A

has photoreceptors synapses and axons of optic nerve

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30
Q

function of the neural layer

A

has neurons that carry impulses to optic nerve and the optic nerve carries it to the occipital lobe to cerebellum where it is interpreted as sight

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31
Q

describe the blind spot

A

no cones or rods, it is the place where the optic nerve and blood vessels and no vision is registered

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32
Q

function of blind spot

A

not sensitive to light

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33
Q

describe the yellow spot

A

centre of retina and it only has cones (macula lutea)

34
Q

function of yellow spot

A

area of greatest clarity

35
Q

name the structures of the retina (4)

A

pigment layer
nervous layer
blind spot
yellow spot

36
Q

name the structures of the nervous layer (2)

A

photoreceptors

neural layer

37
Q

what two cells are in the photoreceptors

A

rods and cones

38
Q

what is the optic nerve

A

a collection of sensory neurons that go to cns

39
Q

describe the lens

A

biconvexed, flexible transparent and refracts light (not set) and is held in place by the suspensory ligaments which are attached to the ciliary body

40
Q

function of the lens

A

can change shape focusing of light on retina

41
Q

describe the suspensory ligaments

A

works with the ciliary body to help lens bend light

42
Q

describe the eye cavities

A

divided by the lens and suspensory ligaments into anterior and posterior

43
Q

describe the anterior cavity

A

constantly refreshing/replenishing with nutrients
front of lens
watery fluid called aqueous humour

44
Q

function of aqueous humour

A

carries away toxins
provides nutrients like oxygen
provides correct pressure in the front of the eye

45
Q

describe the posterior cavity

A

jelly like which is called the vitreous humour

it is also formed when we are embryos and lasts a lifetime

46
Q

functions of the vitreous humour

A

prevents eyeball from collapsing

and is holding retina against choroid

47
Q

what is it when there is a bending of light

A

refraction

48
Q

what is it called when the light rays move apart

A

diverge

49
Q

what is it called when light rays move closer

A

converge

50
Q

explain binocular vision

A

vision with 2 eyes with overlapping fields of view allowing good perception of depth and 3 dimensional images

51
Q

explain pupillary mechanism

A

it is when the circular and radial muscles contract and relax to control the amount of light entering through pupil to retina in response to various light

52
Q

explain accommodation

A

changing the shape of the lens to focus on images from different distances

53
Q

what is myopia

A

short sightedness
condition
where people struggle to focus on object far

54
Q

what hypermetropia

A

long sightedness
condition
where people struggle to see objects from a close to the eye

55
Q

what causes myopia

A

too long eyeball

56
Q

what is going on with the lens and cornea with short sightedness

A

they are TOO CONVEX (too much bulge)

57
Q

remedy for myopia

A

conCAVED lenses! that will DIVERGE the light before the eye

58
Q

what causes hypermetropia

A

too short eyeball

59
Q

what is going on with the lens and cornea withlong sightedness

A

they are too FLAT (little bulge)

60
Q

remedy for hypermetropia

A

conVEXED lenses! that will CONVERGE light before the eye

61
Q

go into detail to explain binocular vision

A

each eye will get a slightly different view of object

as the image enters the posterior cavity it is upside down when it hits the back of the retina then is sent through the optic nerve to the occipital lobe to the cerebellum

then brain combines the 2 views to form a single 3D image

helps with depth perception and size of object

62
Q

hereditary conditions that causes irregularly shaped cornea or lens

A

corneal astigmatism

lenticular astigmatism

63
Q

corneal astigmatism which is bad and which is good

A

rugby ball
soccer ball
respectively

64
Q

lenticular astigmatism which is bad and which is good

A

lens lands on 2 points of retina
one point on retina
respectively

65
Q

what happens if you dont fix it

A

headaches and eye strain

66
Q

what factors could cause it astigmatism

A

scratched, injury or could just be hereditary

67
Q

remedies for astigmatism

A

glasses, contact lenses, or refractive LASER surgery

68
Q

a condition where proteins in lens begin to clumps and clouds the vision and can lead to blindness

A

cataracts

69
Q

what is the lens made of

A

water + protein

70
Q

how can we diagnose cataracts

A

vision tests

check for colour change in the lens might turn yellowish

71
Q

how can we diagnose cataracts

A

vision tests

check for colour change in the lens might turn yellowish

72
Q

In accommodation explain what happens when there is something close

A

It is not natural for the lens to be bulged

Our ciliary contract and suspensory relaxes

73
Q

In accommodation explains what happens when there’s something far

A

It is natural for the lens to be flat because there wouldn’t be a strain
Our ciliary relaxes and suspensory contracts

74
Q

Flat lens + far object

Is it correct? And where does it land

A

Yes and it lands on the retina

75
Q

Flat lens + close object

Is it correct? And where does it land

A

No

It goes past the retina, landing on 2 points making it blurry

76
Q

Bilge lens + far object

Is it correct and where does it land?

A

No

It doesn’t land on the retina

77
Q

state the 3 function of the eye

A

pathway of light rays and image formation
stimulation of photoreceptors
pathways of nerve impulses

78
Q

explain the first step out of 4 for the pathway of light

A

light passes through air and all through the structures of the eye to stimulate photoreceptors

79
Q

explain the second step out of 4 for the pathway of light AND ALSO DISCUSS WHAT HAPPENS DURING REFRACTION

A

refraction when light passes from one substance to another off different density and it’s rays are bent

80
Q

explain the third step out of 4 for the pathway of light

A

the light rays converge to form a focused image on yellow spot of retina

81
Q

explain the fourth step out of 4 for the pathway of light

A

the image shows up smaller than the object and upside down and reversed from left to right all inside the eye then optic nerve send it to the occipital lobe and them cerebellum to fix it, where it is interpreted as sight

BIOLOGY (3 decks)

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