B12 Flashcards
1
Q
For someone with glaucoma, is the AH flow in and out equal?
A
No
2
Q
Is the uveoscleral pathway the minor or major route /pathway in AH outflow?
A
Minor
3
Q
Describe how AH flows in the uveoscleral pathway
A
AH enters the connective tissue between the ciliary muscle bundles, through the suprachoroidal space, and out through the sclera
4
Q
Is the uveoscleral outflow affected by IOP?
A
Nope
5
Q
The outflow rate through the uveoscleral route tends to ____ with age
A
Decrease
6
Q
What are the 3 layers of the TM?
A
- juxtancanalicular
- corneaoscleral
- uveal
7
Q
The corneoscleral pathway is considered the ____ route
A
Major
8
Q
Describe the flow of AH in the corneoscleral pathway
A
AH passes through the TM, across SC, into its lumen
and into draining collector channels, aqueous veins and episcleral veins
9
Q
Is the corneoscleral pathway IOP independent or dependent?
A
dependent
10
Q
An acute rise in EVP results in a ___ ratio of increase IOP
A
1:1
11
Q
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
A
Pumping model
12
Q
In the corneoscleral pathway an increase of IOP causes drainage decrease or increase?
A
Increase
13
Q
What will make schlemm’s canal collapse on itself and obstruct into the venous system?
A
Constant, very high IOP
14
Q
What 2 fluid compartments is the TM suspended between?
And are these at the same or different pressures?
A
Anterior chamber and schlemms canal
They have different pressures
15
Q
What 5 things can cause AH outflow obstruction through occlusive angles?
A
- severe diabetes
- uveitis
- hyphema
- pseudoexfoliative glaucoma
- pigment dispersion glaucoma
16
Q
In humans, ___% of the resistance to the AH outflow is localized to the TM, and ___% occurs beyond schlemm’s canal
A
75% to TM
25% to SC
17
Q
Can an injury to the TM cause an obstruction of AH outflow?
A
It sure can
18
Q
What are the 3 long term influences on IOP?
A
- genetics
- gender
- refractive error
19
Q
What are the 6 short term influences on IOP?
A
- diurnal
- postural variation
- lid and eye movement
- systemic conditions
- environmental conditions
- food and drugs
20
Q
T/F: IOP is under hereditary influence
A
True
21
Q
Are IOP’s different between men and women in the ages of 20-40?
A
Nope, they are equal
22
Q
In older age groups, do men or women have a increase in mean IOP?
A
Women
23
Q
Myopic people have a ____ incidence of open angle glaucoma
A
Higher
24
Q
T/F: there is a positive correlation between IOP and both axial length and increasing degrees of myopia
A
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
