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Flashcards in B12 Deck (164):
1

For someone with glaucoma, is the AH flow in and out equal?

No

2

Is the uveoscleral pathway the minor or major route /pathway in AH outflow?

Minor

3

Describe how AH flows in the uveoscleral pathway

AH enters the connective tissue between the ciliary muscle bundles, through the suprachoroidal space, and out through the sclera

4

Is the uveoscleral outflow affected by IOP?

Nope

5

The outflow rate through the uveoscleral route tends to ____ with age

Decrease

6

What are the 3 layers of the TM?

-juxtancanalicular
-corneaoscleral
-uveal

7

The corneoscleral pathway is considered the ____ route

Major

8

Describe the flow of AH in the corneoscleral pathway

AH passes through the TM, across SC, into its lumen
and into draining collector channels, aqueous veins and episcleral veins

9

Is the corneoscleral pathway IOP independent or dependent?

dependent

10

An acute rise in EVP results in a ___ ratio of increase IOP

1:1

11

When the aqueous outflow pump receives power from transient increases in IOP such as occur in systole of the cardiac cycle during blinking and during eye movement

Pumping model

12

In the corneoscleral pathway an increase of IOP causes drainage decrease or increase?

Increase

13

What will make schlemm's canal collapse on itself and obstruct into the venous system?

Constant, very high IOP

14

What 2 fluid compartments is the TM suspended between?

And are these at the same or different pressures?

Anterior chamber and schlemms canal

They have different pressures

15

What 5 things can cause AH outflow obstruction through occlusive angles?

-severe diabetes
-uveitis
-hyphema
-pseudoexfoliative glaucoma
-pigment dispersion glaucoma

16

In humans, ___% of the resistance to the AH outflow is localized to the TM, and ___% occurs beyond schlemm's canal

75% to TM
25% to SC

17

Can an injury to the TM cause an obstruction of AH outflow?

It sure can

18

What are the 3 long term influences on IOP?

-genetics
-gender
-refractive error

19

What are the 6 short term influences on IOP?

-diurnal
-postural variation
-lid and eye movement
-systemic conditions
-environmental conditions
-food and drugs

20

T/F: IOP is under hereditary influence

True

21

Are IOP's different between men and women in the ages of 20-40?

Nope, they are equal

22

In older age groups, do men or women have a increase in mean IOP?

Women

23

Myopic people have a ____ incidence of open angle glaucoma

Higher

24

T/F: there is a positive correlation between IOP and both axial length and increasing degrees of myopia

True

25

Does IOP change throughout the day?

Yep

26

When is the peak of IOP?

In the morning

27

T/F: IOP decreases changing from sitting to the supine position

False, it increases

28

Patient with systemic hypertension will have a greater IOP increases after ___ min in supine

15 minutes

29

Does blinking raise IOP?

Yes, by 10mmHg

30

How much does hard lid squeezing raise IOP?

As much as 90mmHg

31

In what gaze is there in increase in IOP in normal individuals?

Up gaze

32

Thicker corneas cause artificially ____ readings

High

33

Thinner corneas cause artificially ___ readings

Low

34

T/F: patients with HIV have lower than normal mean IOPs

True

35

Are IOPs increased or decreased during pregnancy?

Decreased

36

Does exposure to cold air increase or decrease IOP? And why

Decreases, because episcleral venous pressure is decreased

37

Does reduced gravity cause an increase or decrease in IOP?

Increase

38

Does alcohol increase or decrease IOP?

Decrease

39

Does caffeine cause an increase or decrease in IOP?

Slight transient rise

40

Does smoking increase or decrease your IOP?

Increase

41

Do heroin and marijuana increase or decrease IOP?

Decrease

42

Does LSD increase or decrease IOP?

Increase

43

Do corticosteroids increase or decrease IOP?

Increase

44

What it the major pathway of AH outflow?

Corneoscleral pathway

45

What AH pathway is IOP independent?

Uveoscleral pathway

46

Does AH pass through the SC in the uveoscleral pathway?

No

47

An acture increase in EVP by 4mmHg will theoretically cause an increase in IOP by?

4mmHg

48

T/F: thicker cornea can cause an artificially high IOP reading

True

49

What is the largest organ of the eye?

Vitreous

50

The vitreous transmits ____ of light

90%

51

The vitreous is located between the ___ and the _____

Crystalline lens and the retina

52

What are the 3 zones of the vitreous?

Outermost zone (vitreous cortex)
Center zone (cloquets canal)
Intermediate zone (inner to the cortex and surrounds the center canal)

53

The vitreous is attached to what part of the retina?

Inner limiting membrane

54

What attaches the vitreous to the ILM?

Anchoring fibrils and the membrane limitans interna (MLI)

55

What 3 things is the MLI composed of?

-fusing point of the anchoring fibrils
-lamina densa
-lamina Lucida

56

The vitreous base is located at the ____

Ora serrata

57

The vitreous base is ___mm broad annular region

1.5

58

The vitreous base is attached to the ___ and the ____

Nonpigmented epithelium of the ciliary body and the internal limiting membrane of the peripheral retina

59

What is the strongest attachment to the vitreous?

Vitreous base

60

Does the vitreous base decline with age?

No

61

A vitreous attachment that is between the posterior surface and the anterior face of the vitreous

Wiegers ligament

62

Does the wiegers ligament decline with aging?

Yes

63

The vitreous attached around the edge of the optic disc?

Peripapillary adhesion

64

Does wiegers ligament have a firm or medium attachment?

Firm

65

Does the peripapillary adhesion have a firm or medium vitreal attachment?

Medium attachment

66

Is the macular and peripheral retinal attachment firm, medium or weak?

Weak

67

What are the 4 vitreous attachements?

-vitreous base
-wiegers ligament
-peripapillary adhesion
-macular and peripheral retinal attachment

68

The gel structure of the vitreous results from the arrangement of collagen fibrils suspended in a network of ______

Hyaluronic acid

69

What are the 3 vitreal cells?

-hyalocytes
-fibroblasts
-macrophages

70

What 2 things does hyalocytes synthesize?

-HA
-glycoproteins from the collagen fibrils

71

What do fibroblasts synthesize?

Collagen fibrils

72

What are the 4 functions of the vitreous?

-support for retina
-diffusion barrier
-metabolic buffer
-transparency

73

What is the strongest vitreal attachment?

Vitreous base

74

Does the peripapillary adhesion decline with age?

Yes

75

What is the major composition of the vitreous?

Water

76

What are the 5 main vitreous components?

-water
-type 2 collagen
-HA
-vitreal cells
-vitamin C

77

What makes up the majority of the vitreal cells?

Hyalocytes

78

What are the 5 support functions of the vitreous?

-prevents retinal detachment
-reduced mechanical deformation
-supports the lens during trauma
-decreases transmission of light at 300-350nm
-mechanical support of limited significance

79

What is the most common pathological condition of the vitreous?

PVD

80

If you have macular edema will you have increased or decreased osmotic pressure?

Increased

81

____ traction can cause macular edema

Vitreous-retinal

82

T/F: Diffusion is slow and bulk flow is limited across the vitreous

True

83

This prevents topically administered substances from reaching the retina and prevents substances in the blood stream from reaching the vitreous center

Diffusion barrier

84

What vitamin type does the vitreous have a lot of?

Vitamin C

85

In the case of a vitrectomy or full PVD what 3 things could occur?

-nuclear sclerotic cataract (due to oxidative damage)
-reduce neovascularization in the retina (due to reduced VEGF)
-neovascular glaucoma (due to no barrier)

86

Does the vitreous have high or low concentration of structural macromolecules and soluble proteins?

Low

87

What 2 pathologies can block the transparency of the vitreous?

-synchisis scintillations
-asteroid hyalosis

88

What causes gel structure of vitreous?

HA provide spacing and support for the collagen

89

What substance maintains high concentration in vitreous and can be utilized to protect the retina from metabolic and light-induced free radicals?

Vitamin C

90

What substance products the retina from oxidative damage?

Vitamin C

91

What are vitreous functions?
A. Provides a transparent medium
B. Cushion the globe
C. Storage area of ions and nutrients for the retina and lens

All of the above

92

What 4 things make up the transparency of the vitreous?

-Low concentration of structural macromolecules
-Low concentration of soluble proteins
-Specific collagen/HA configuration
-Blood/vitreous barrier

93

A disorder of the tear film caused by tear deficiency
or excessive tear evaporation that causes damage to the interpalpebral ocular surface and is associated with symptoms of ocular discomfort

Dry eye syndrome

94

What are the 3 functions of the tear film?

- Provides a smooth refractive surface for clear vision
- Maintains the health of corneal and conjunctival
epithelia
- Acts as the 1st line of defense against microbial
infections

95

What are the 3 layers of the tear film?

-mucous layer
-aqueous layer
-lipid layer

96

High molecular weight glycoproteins that are heavily glycosylated

Mucin

97

The mucous layer o the tear film is between what 2 layers?

Epithelial layer and aqueous layer

98

The mucus layer of the tear film is composed mostly of what kind of substance?

Mucin

99

What are the 2 different types of mucin?

-membrane associated mucin
-secretory mucins

100

Type of mucin: A dense barrier to pathogen penetrance, at the epithelia cell-tear film interface

Membrane associated mucin

101

Type of mucin: act as “cleaning crew”, moving through the tear fluid and collecting debris that can be removed via the nasolacrimal duct during blinking

Secretory mucins

102

What are the 4 functions of the mucus layer in the tear film?

-Maintain water on the surface of the eye
-Interacts with tear lipids layer to lower surface tension thereby stablizing the tear film
-Provides lubrication for eyelid movement
-Traps exploited surface cell, foreign particles and bacteria

103

What are the 2 sources to the mucus layer?

-goblet cells of conjunctiva
-squamous cells of the cornea and conj

104

What type of neural control of the mucus layer increases the mucus secretion?

Parasympathetic nerve

105

What 3 nerves are sources for the mucus layer of the tear film?

-sensory nerves
-parasympathetic nerves
-sympathetic nerves

106

The aqueous layer of the tear film is composed of what 7 things?

-water
-electrolytes
-proteins
-peptide growth factors
-vitamins
-hormones

107

What are the main contributors to osmolarity of the tear film?

Na and Cl

108

Does osmolarity increase or decrease with dry eye?

Increases

109

What are the 2 ions that are important for maintaining corneal epithelium health?

K and Ca

110

What are the 4 important electrolytes of the tear film?

-Na
-Cl
-K
-Ca

111

What peptide growth factors are in the aqueous layer of the tear film?

-EGF
-TGF-B
-HGF
-Vitamin A

112

What acts as a buffer to maintain constant pH and contributes to maintaining epithelial integrity of the ocular surface?

Electrolytes

113

The buffering system allows the eye to tolerate the ophthalmic solution varying in pH from ___ to ___ in the aqueous layer

3.5 to 10.5

114

During sleep, does pH increase or decrease?

Decreases

115

Does pH increase or decrease in dry eye due to osmolarity increasing

Increases

116

What are the 3 functions of the aqueous layer of the tear film?

-strong defense system protecting it from invaders
-peptide growth factor and vitamin A regulate epithelial proliferation, motility, and differentiation
-buffering

117

What type of tearing does the main lacrimal glands deal with?

Reflex and emotional tearing

118

What type of tearing does accessory lacrimal glands deal with?

Maintenance tearing

119

What types of neural control does the main lacrimal glands receive ?

Parasympathetic, sympathetic, and sensory

120

What type of neural control do the accessory lacrimal glands receive?

Parasympathetic

121

They aqueous layer is between what two layers?

Mucous layer and lipid layer

122

What is the lipid layer of the tear film composed of?

Meibomian oil

123

What are the 2 phases of the lipid layer of the tear film?

1.) polar surfactant phase
2.) nonpolar phase (overlaid polar phase)

124

The polar surfactant phase is primarily composed of what 2 things?

-phospholipids and glycolipids

125

This phase acts as a surfactant between the hydrophilic aqueous mucin layers and the thick, nonpolar lipid layer

Polar surfactant phase

126

What 3 things make up the nonpolar phase of the lipid layer?

-wax
-cholesterol esters
-triglycerides

127

This phase provides the air-tear film interface and is responsible for retarding evaporation

Non-polar phase

128

What are the 4 functions of the lipid layer of the tear film?

-Major barrier to evaporation from the ocular surface (slows evaporation)
-Provides stability to the tear film through interaction with aqueous-mucin phase
-Provides a smooth optical surface for the cornea
-Acts as a barrier against foreign particles

129

What is the main sources to the lipid layer of the tear film?

-meibomian glands

130

What 2 other sebaceous glands assist the meibomian gland in the lipid layer?

Zeis and moll

131

Glycocalyx is produced by what? And what do they do?

Corneal epithelial surface cells

They help bind mucins onto the corneal surface

132

What 4 tests are used to evaluate tear secretion?

-schirmer 1
-schirmer 2
-phenol red thread test
-meinscometry

133

What 4 tests are used to evaluate tear film stability?

-TBUT
-ocular protection index
-videokeratography
-tear turnover

134

What 3 tests are used to evaluate tear film osmolarity?

-tear film osmolarity
-tear ferning
-tear evaporation

135

What 2 tests are used to evaluate the lipid layer of the tear film?

-infererometry
-meibometry

136

What 3 tests are used to evaluate the ocular surface of the tear film?

-fluorescein
-rosa bengal
-lissamine green

137

What is the largest category of dry eye?

Tear deficient dry eye

138

If there is a disorder in lacrimal gland function, what type of dry eye will be induced?

Tear deficient dry eye

139

A type of dry eye that results in either reduced aqueous tear production and tear flow, or a failure to transfer lacrimal fluid into the conjunctival sac

Tear deficient dry eye

140

A type of dry eye where the lacrimal gland function is normal and the volume of lacrimal fluid is sufficient to cover the ocular surface, but another tear abnormality exists that leads to increased tear evaporation.

Evaporation dry eye

141

What is the resource in generating mucins in tear film?

Goblet cells and squamous cells of cornea and conj

142

What electrolytes are the main contributors for osmolarity of tear film?

Na and Cl

143

What is the resource of generating the aqueous layer in the tear film?

Main lacrimal gland and accessory lacrimal gland

144

What later is the major barrier to evaporation from the ocular surface?

Lipid layer

145

Does the anterior chamber depth increase or decreased with age?

Decrease

146

What type of cataract has more of an effect on reducing anterior chamber death?

Cortical cataract

147

Is uveoscleral outflow increased or decreased wth aging?

Reduced but there is an increase in the amount of connective tissue in the ciliary muscle

148

What are the 4 aging changes in the anterior chamber?

- reduced anterior chamber depth
-reduced uveoscleral outflow
-accumulation of extracellular matrix plaque in TM
-increased outflow resistance in the TM and SC

149

T/F: the gel structure becomes more liquefied with aging

True

150

What is the most common cause of a PVD?

Vitreous syneresis

151

The breakdown of the vitreous gel and aggregation of collagen fibrils due to increase of liquid portion

Vitreous syneresis

152

Change of gel structure is most likely to occur in the periphery or the center?

Center

153

Aggregation of collagen fibrils

Floaters

154

What are the 5 aging changes of the lacrimal system?

-goblet cell population may decrease
-reduced tear reflex secretion
-change in composition of the meibomian secretion
-increase of plugged meibomian gland pores
-reduced lacrimal drainage capacity

155

How does B-lysine function to destroy a pathogen?

Acts like a detergent and pokes hole in the cell membrane releasing bacterial cytoplasm to the external environment

156

This enzyme binds to the microbial cell membrane, embeds in the membrane, and forms pore like membrane defects that allow the efflux of ions and nutrients

Defensins

157

Does a Defensin function like a detergent?

No

158

Structurally similar chemicals that have similar activities to defensins

Mimetics

159

What is the type of bacteria does lysozyme play major effect on?

Gram + bacteria

160

This enzyme breaks bonds between peptidoglycan sugar residues and disrupts cell wall integrity promoting membrane rupture

Lysozyme

161

What does lactoferrin bind to?

Iron and other metal ions

162

What does lactoferrin do?

Takes up nutrients needed for bacterial growth

163

Lactoferrin is associated with what type of cancer?

How?

Breast cancer
Because when it is lacking there is an increased risk of infection

164

Lactoferrin is decreased in what type of dry eye disease?

Sjögren’s syndrome