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Histo Exam 4 > Eye > Flashcards

Eye Flashcards

1
Q

the wall of the eye has how many layers?

A

3

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2
Q

the outer fibrous coat of the eye is composed of what structures

A

cornea and sclera

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3
Q

the middle layer of the eye is also called the

A

vascular (uveal) coat

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4
Q

the middle layer is composed of what structures

A

iris ciliary body, choroid

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5
Q

the inner layer of the eye is also called the

A

retinal coat

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6
Q

the inner layer is composed of what structures

A

retinal pigmented epithelium (RPE) & neural retina

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7
Q

the eye contains how many chambers

A

3 chambers: anterior, posterior and vitreous cavity

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8
Q

the anterior chamber’s boundaries are

A

between cornea and iris

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9
Q

the posterior chamber’s boundaries are

A

between back of iris and lens with attached fibers

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10
Q

vitreous cavity is defined by what structures

A

lens to retina

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11
Q

the portion of exposed surface of the eye which is continuous onto the inner surface of the eyelid is called

A

conjunctiva

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12
Q

the cornea is (transparent/translucent/opaque) and has a (convex/concave) shape that aids in focusing light & images on retina

A

transparent

convex

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13
Q

(t/f) the cornea is avascular

A

true

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14
Q

where does the cornea get its nutrients from?

A

central part of the cornea gets nutrients by diffusion from the aqueous humor, & peripheral part supplied by blood from limbus vessels

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15
Q

the cornea has how many layers?

A 
5 different layers:
epithelium
bowman's layer
stroma
decemet's membrane
corneal endothelium
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16
Q

because the cornea has no blood flow, what is something unique to the cornea

A

it can be transplanted without rejection

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17
Q

corneal epithelium has what type of epithelium

A

anterior layer

non-keratinized strat. squam. epithelium with small microvilli

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18
Q

can corneal epithelium regenerate

A

yes

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19
Q

can corneal epithelium feel pain? and if yes, through what nerves

A

yes, through trigeminal and oculomotor nerves

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20
Q

bowman’s layer is composed of what structures

A

type 1 collagen

part of stroma

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21
Q

can bowman’s layer regenerate

A

no

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22
Q

stroma is a lattice of what collagen fibers

A

type 1 and type 4 collagen fibers

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23
Q

stroma’s ECM is rich in what compounds?

A

chondroitin and keratan sulfate

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24
Q

what is so special about Decemet’s membrane?

A

**Thick basement membrane (contains type VII collagen)

produced by corneal endothelium

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25
Q

corneal endothelium’s surface faces which direction?

A

surface faces anterior eye chamber

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26
Q

what is unique to the corneal endothelium

A

impermeable intercellular spaces prevent leakage of fluid into corneal stroma

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27
Q

sclera is composed of what type of tissue

A

dense irregular connective tissue (opaque)

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28
Q

what is the generic function of sclera

A

provides protection and structural support & insertion point for extraocular muscles

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29
Q

where is the limbus

A

its at the corneoscleral junction

adjacent to trabecular meshwork & canal of Schlemm

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30
Q

the aqueous humor resembles what bodily fluid

A

resembles plasma - less protein

31
Q

aqueous humor is produced by what structure

A

ciliary body

32
Q

how does aqueous humor flow

A

from ciliary body > anterior chamber > trabecular network > canal of Schlemm > aqueous veins > episcleral veins

33
Q

obstruction of aqueous humor flow leads to what condition

A

glaucoma

34
Q

the middle (vascular) coat contains what structures

A

choroid, ciliary body, and iris

35
Q

choroid is a (avascular/highly vascular) structure

A

choroid is a highly vascular nutrient supplier to all eye layers

36
Q

choroid also contains what compound

A

melanin

37
Q

ciliary body contains what two portions

A

uveal & neuroepithelial portion

38
Q

so what is the uveal layer mean?

A

it’s the outer layer of choroid (supraciliaris) and ciiliary muscle attached to suspensory ligament and layer of fenestrated capillaries

39
Q

neuroepithelial has two layers composed of

A

2 layers of ciliary epithelium consisting of outer pigmented layer continuous with retinal pigmented epithelium and inner nonpigmented layer

40
Q

the anterior portion of the ciliary body epithelium is folded to form what structure

A

ciliary processes

41
Q

epithelium in the region containing ciliary processes produce what structure

A

aqueous humor

42
Q

the iris is a continuation of what structure

A

iris is a continuation of the ciliary body

43
Q

what controls the size of the pupil?

A

anterior part of middle coat (uvea) has smooth muscle

44
Q

the two smooth muscle layers in the iris

what are they innervated by

A

circular and radial
circular = pupil constrictor = psy
radial = pupil dilator = symp

45
Q

characteristics of the lens

A

avascular
transparent
elastic
biconvex in shape

46
Q

the lens is enclosed in what structure

A

capsule = thick basement membrane like material

47
Q

what helps the lens change shape

A

change of tension on suspensory ligament fibers (zonular fibers)

48
Q

what are the components of vitreous humor

A

water + hyaluronic acid

49
Q

characteristics of vitreous humor

A

gel-like, transparent fluid
fills vitreous chamber
function is to keep lens and retina in place

50
Q

what is a cataract

A

opacity of lens associated with aging

51
Q

what layer of the eye absorbs scattered light rays

A

retinal pigmented epithelium

52
Q

what are the three functions of retinal pigmented epithelium

A

absorbs scattered light rays
phagocytosis of worn out discs shed from rods
stores & releases vitamin A to photoreceptors

53
Q

RPE closely adheres to what structure

A

to choroid

54
Q

trauma to the retina could be dangerous because

A

it could dislodge the retina at its space between RPE and rest of retina

55
Q

general description of rods

A 
tall cylindrical cells 
function in low light & peripheral vision
outer segments = modified cilia
have discs derived from plasma membrane containing rhodopsin pigment
56
Q

what is the function of rhodopsin pigment

A

tranducer of light energy

57
Q

general description of cones

A 
shortern cone-shaped cells
color vision & bright light
outer segments = modified cilia
have discs and pigments sensitive to red, green, & blue light
located more centrally
58
Q

what structure has only cones

A

fovea contains only cones

59
Q

describe renewal of photoreceptors

A

outer discs of old rods shed into space between outer segements & RPE which phagocytize them

new discs made from below & move upward replacing the old

cones shed & replace more slowly

60
Q

what are the macula lutea & optic disc

A

posterior retinal landmarks that are viewed through pupil by a scope

61
Q

optic disc

A

papilla where optic nerve fibers exit retina, no photoreceptors

62
Q

fovea and its importance

A

pit in the center of macula
important for visual acuity
cones highly represented in optic nerve & visual cortex = “macular vision”

63
Q

does the macula have any retinal vessels

A

no, but choroid vessel are abundant on the outside

64
Q

detached retina is a separation of what

A

neural retina separates from RPE & from choroidal capillaries which feed photoreceptors, especially in fovea

65
Q

age related macular degeneration is a leading cause of

A

blindness

66
Q

what happens in macular degeneration

A

macular area & fovea lose function due to pigment epithelium behind the retina degenerating & forming drusen -> allows fluid leakage behind fovea

67
Q

what is drusen

A

white spots seen with macular degeneration

68
Q

what happens when fovea cones die?

happens in macular degeneration

A

central vision loss, cannot read or see fine detail

69
Q

glaucoma

A

elevated pressure in eye, common problem in aging
pressure rises because failure of anterior chamber to exchange fluid properly
compromises blood vessels of optic nerve & also axons of ganglion cells

70
Q

retinitis pigmentosa

A

hereditary disease - no cure, multiple forms
rods of peripheral retina degen. in early stages
night blindness and then development of tunnel vision - only fovea spared
black pigment in peripheral retina & thinned blood vessels @ optic nerve head

71
Q

first sign of retinitis pigmentosa

A

night blindness

72
Q

diabetic retinopathy

A

eye blood vessels become distorted & multiply

tx: laser treatment to stop blood vessel proliferation & fluid leakage

73
Q

hereditary retinal dystrophy

A

inability of RPE to phagocytize worn out discs from rods

74
Q

what is the structure and function of the lacrimal gland

A

compound tubuloalveolar gland
secretes tears which drain by ducts into conjunctival region
tears contain lysozyme

Histo Exam 4 (3 decks)

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