Eye Anatomy Flashcards

1
Q

Eye

description? how many layers? what are they?

A
2.5 diameter
wall of eyeball consists of 3 layers:
-fibrous tunic: outer layer 
-vascular tunic: middle layer 
-retina: inner layer
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2
Q

Fibrous Tunic

composed of ? (2)

A

cornea

sclera

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3
Q

Cornea

description? what does it do?

A

transparent covering of iris
admits & refracts light into eye- helps focus light onto retina
(bulges out)

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4
Q

Sclera

description? what does it do?

A

(cornea turns into this)
“white” of the eye- dense connective tissue
provides shape to eyeball (outer layer)
attachment for eye muscles

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5
Q
Vascular Tunic (Uvea) 
composed of ? (3)
A

(called Uvea bc of UV light)
choroid
ciliary body
iris

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6
Q

Choroid

function? location? description? contains? which do what?

A

lines sclera
posterior portion of tunic
vascular
contains melanocytes- appears black/brown
-prevents reflection & scattering of light

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7
Q

Ciliary body

A
anterior portion of tunic
contains melanocytes (dark brown appearance)
parts:
 -ciliary processes
 -ciliary muscle
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8
Q

ciliary processes definition?

A

vascular folds of internal surface of ciliary body

- secretes aqueous humor (watery)

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9
Q

ciliary muscle definition ?

A

(connected to iris)
circular band of smooth muscle
-muscle contraction changes lens shape
-adapts for near or far vision

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10
Q

iris

description? how is color determined? location? made of? function?

A
colored portion of eyeball 
 -determined by amount of melanin 
attached to ciliary processes
made of melanocytes & smooth muscle fibers
regulates amount of light into eyeball
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11
Q

pupil

A

opening in center of iris\

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12
Q

coloboma

A

irregular shaped iris
-pupil is NOT circular
(does not affect sight, happens in fetus)

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13
Q

heterochromia iridum

A

2 different colored iris

EX: blue and green eye

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14
Q

Lens, is it part of vascular tunic?

A

No, its not a part of the vascular tunic, it only sits in that area

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15
Q

Lens
description?
contains?
function?

A
(hard & semi-transparent)
behind pupil & iris
contains proteins - crystallins
    -arranged in layers
lacks blood vessels
helps focus images on retina (help focus light on it)
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16
Q

Interior eyeball cavities

whats divided into 2 cavities? what are they?

A
lens divides eye into 2 cavities :
anterior cavity
vitreous chamber (posterior cavity)
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17
Q

Anterior cavity

filled with? functions?

A

(watery)
filled w/ aqueous humor
-maintains shape of eyeball
-supplies oxygen & nutrients to lens & cornea

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18
Q

Posterior cavity aka Vitreous Chamber

A
(jelly)
Large cavity behind lens
-filled w/ vitreous body
    -jelly-like substance
    -maintain shape of eyeball
    -keeps retina attached to choroid
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19
Q

how are the cavities held together?

A

held together by pressure

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20
Q

retina

description? consists of?

A

inner layer of eyeball, posterior 3/4 of eyeball
Consists of:
-pigmented layer- melanin
-neural (sensory) layer- processes visual data

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21
Q

Pigmented layer

A

(contains melanin)

helps absorb light rays

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22
Q

Neural (sensory) layer

A
(processes visual data)
3 layers:
-Photoreceptors (rods & cones)
-Bipolar cell layer 
-Ganglion cell layer
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23
Q

Other Areas on Retina (3)

A

Macula lutea
Fovea centralis
Optic disc

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24
Q

Macula lutea

description? location?

A

small flat spot
exact center posterior region of retina
visual axis of eye

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25
Q
Macular Degeneration (in macula lutea)
where does it occur? what is it? what happens?
A

Degenerative disorder of retina

  • occur in region of macula lutea
  • lose acute vision, but have peripheral vision
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26
Q

Fovea centralis

location? contains? known for?

A

small depression in center of macula lutea
contains ONLY CONES
area of highest visual resolution

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27
Q

Optic disc

location? also known as?

A

where ganglion axons collect & exit eyeball as optic nerve 1 (joins which is why its #1)
AKA ‘blind spot’ - no rods & cones

28
Q

Photoreceptors of Retina

function? what are the photoreceptors of retina? (2)

A

convert high rays to nerve impulse

  • rods
  • cones
29
Q

rods

how many? allows/ does not allow?

A

120 million
enables to see dim light
does NOT provide color vision (dark & light adjustments)

30
Q

cones

how many? types?

A

6 million
stimulated by bright light
3 types: blue (blue light), Green (green light), Red (right light)
-color vision results from combinations of the 3 types of cones being stimulated

31
Q

Image Formation (3)

A

1) Refraction (bending) of light rays
2) Accommodation
3) Constriction (narrowing) of Pupil

32
Q

Refraction (bending) of light rays

A

75% refraction through cornea
25% refraction through lens
image is inverted on retina

33
Q

Accommodation

what is it? depends on? what controls it?

A
change in shape of lens
depends on distance of object
-distance objects: lens is flatter (ciliary muscles pull)
-close objects: lens is more spherical 
ciliary muscle controls lens shape
34
Q

Constriction (narrowing) of Pupil

A

circular muscles of iris control pupil diameter

35
Q

Photopigments & vision

function? description? contain?

A
absorb light
colored protein molecules 
initiates events for nerve potentials
rods contain rhodosin
-purplish color
cones contains 3 different types of pigments
photopigments contain:
-opsin 
-retinal
36
Q

opsin

A

protein molecule (photopigment contains this)

37
Q

retinal

A

(photopigment contains this)
vitamin A derivative
-light absorbing part of photopigment

38
Q

Brain pathway & visual fields

types of visual fields? binocular vision?

A

binocular vision- both eyes focus on 1 set of objects
Each eye visual field:
Nasal (Central) half
Temporal (Peripheral) half

39
Q

Nasal (Central) half

A

light rays from nasal half will fall on the temporal half of the retina

40
Q

Temporal (Peripheral) half

A

light rays from temporal half will fall on the nasal half of the retina

41
Q

how is visual info conveyed ?

A

visual info from the RIGHT half of each visual field is conveyed to the LEFT side of the brain and vice versa

42
Q

nearsighted/ farsightedness

another name for each?

A

nearsightedness - myopia

farsightedness - hyperopia

43
Q

nearsightedness (myopia)

corrected with? what is it? where?

A

see close objects
focal point in front of retina
corrected w/ concave lens

44
Q

farsightedness (hyperopia)

what is it? where? corrected with?

A

see far objects
focal point behind retina
corrected w/ convex lens

45
Q

Astigmatism

definition?

A

either cornea or lens has irregular curvature

get multiple focal points- parts of image is unfocused or distorted

46
Q

choroid , choroid coat

A

posterior 5/6 of middle (vascular) layer loosely joined to sclera

47
Q

sclera

A

white part of outer (fibrous) layer

48
Q

cornea

A

transparent anterior portion of outer layer

49
Q

conjunctiva

A

inner lining of eyelid

50
Q

lacrimal gland

A

secretes tears

51
Q

vitreous humor

A

fills posterior cavity

52
Q

optic disc

A

area where optic nerve exits eye

53
Q

iris

A

smooth muscle that controls light entering the eye

54
Q

aqueous humor

A

fills anterior and posterior chambers of anterior cavity of the eye

55
Q

retina

A

contains visual receptors called rods & cones

56
Q

suspensory ligaments, zonula fibers

A

connects lens to ciliary body

57
Q

ciliary muscle

A

cause lens to change shape

58
Q

structures & fluids through which light passes as it travels from the cornea to retina

A
cornea
aqueous humor
pupil of iris
lens
vitreous humor
retina
59
Q

what tissue is responsible for the toughness in the eye?

A

dense connective tissue

60
Q

where’s aqueous humor in the eye?

A

anterior cavity (btwn cornea and lens)

61
Q

function of dark pigment in choroid coat?

A

absorbs excess light

62
Q

Extrinsic eye muscle: superior rectus

A

up and in

63
Q

Extrinsic eye muscle: medial rectus

A

inward

64
Q

Extrinsic eye muscle: inferior oblique

A

up and out

65
Q

Extrinsic eye muscle: inferior rectus

A

down and in

66
Q

Extrinsic eye muscle: lateral rectus

A

outward

67
Q

Extrinsic eye muscle: superior oblique

A

Down and out