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Honors Anatomy & Physiology > Eye Anatomy > Flashcards

Flashcards in Eye Anatomy Deck (67):
1

Eye
description? how many layers? what are they?

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

2

Fibrous Tunic
composed of ? (2)

cornea
sclera

3

Cornea
description? what does it do?

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

4

Sclera
description? what does it do?

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

5

Vascular Tunic (Uvea)
composed of ? (3)

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

6

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

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

7

Ciliary body

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

8

ciliary processes definition?

vascular folds of internal surface of ciliary body
- secretes aqueous humor (watery)

9

ciliary muscle definition ?

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

10

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

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

11

pupil

opening in center of iris\

12

coloboma

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

13

heterochromia iridum

2 different colored iris
(EX: blue and green eye)

14

Lens, is it part of vascular tunic?

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

15

Lens
description?
contains?
function?

(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)

16

Interior eyeball cavities
whats divided into 2 cavities? what are they?

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

17

Anterior cavity
filled with? functions?

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

18

Posterior cavity aka Vitreous Chamber

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

19

how are the cavities held together?

held together by pressure

20

retina
description? consists of?

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

21

Pigmented layer

(contains melanin)
helps absorb light rays

22

Neural (sensory) layer

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

23

Other Areas on Retina (3)

Macula lutea
Fovea centralis
Optic disc

24

Macula lutea
description? location?

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

25

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

Degenerative disorder of retina
-occur in region of macula lutea
-lose acute vision, but have peripheral vision

26

Fovea centralis
location? contains? known for?

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

27

Optic disc
location? also known as?

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

28

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

convert high rays to nerve impulse
-rods
-cones

29

rods
how many? allows/ does not allow?

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

30

cones
how many? types?

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

Image Formation (3)

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

32

Refraction (bending) of light rays

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

33

Accommodation
what is it? depends on? what controls it?

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

Constriction (narrowing) of Pupil

circular muscles of iris control pupil diameter

35

Photopigments & vision
function? description? contain?

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

opsin

protein molecule (photopigment contains this)

37

retinal

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

38

Brain pathway & visual fields
types of visual fields? binocular vision?

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

39

Nasal (Central) half

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

40

Temporal (Peripheral) half

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

41

how is visual info conveyed ?

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

42

nearsighted/ farsightedness
another name for each?

nearsightedness - myopia
farsightedness - hyperopia

43

nearsightedness (myopia)
corrected with? what is it? where?

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

44

farsightedness (hyperopia)
what is it? where? corrected with?

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

45

Astigmatism
definition?

either cornea or lens has irregular curvature
get multiple focal points- parts of image is unfocused or distorted

46

choroid , choroid coat

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

47

sclera

white part of outer (fibrous) layer

48

cornea

transparent anterior portion of outer layer

49

conjunctiva

inner lining of eyelid

50

lacrimal gland

secretes tears

51

vitreous humor

fills posterior cavity

52

optic disc

area where optic nerve exits eye

53

iris

smooth muscle that controls light entering the eye

54

aqueous humor

fills anterior and posterior chambers of anterior cavity of the eye

55

retina

contains visual receptors called rods & cones

56

suspensory ligaments, zonula fibers

connects lens to ciliary body

57

ciliary muscle

cause lens to change shape

58

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

cornea
aqueous humor
pupil of iris
lens
vitreous humor
retina

59

what tissue is responsible for the toughness in the eye?

dense connective tissue

60

where's aqueous humor in the eye?

anterior cavity (btwn cornea and lens)

61

function of dark pigment in choroid coat?

absorbs excess light

62

Extrinsic eye muscle: superior rectus

up and in

63

Extrinsic eye muscle: medial rectus

inward

64

Extrinsic eye muscle: inferior oblique

up and out

65

Extrinsic eye muscle: inferior rectus

down and in

66

Extrinsic eye muscle: lateral rectus

outward

67

Extrinsic eye muscle: superior oblique

Down and out