Quiz 2 OP
During blink, when do the puncta start to close? Eyelid downward moving, about 1/3 closed Eyelid downward moving, about 2/3 closed Eyelid totally closed Eyelid upward moving, about 1/3 open Eyelid upward moving, about 2/3 open
Eyelid downward moving, about 1/3 closed As the eyelids close, the tears move in which of the following sequences?
What's the diff btw facility and resistance
Facilty is the capacity to drain fluid out and Resistance is the flow AGAINST outflow.
How is the water binding capacity of GAG's affected with aging
GAG's hold more water as we age causing an increase in resistance to outflow
"the balance btw cells and ECM is critical" When this is out of balance what occurs
Glaucoma
Which of the following statements regarding the aqueous humor is correct a. Is derived from the ciliary body and the iris root b. Total turnover time is 3.5 hours c. Has a low level of protein d. Is exposed to a high ambient oxygen tension relative to the tears e. Leaves the eye largely via uveoscleral flow
Has a low level of protein
How is Aqueous formation affected by dinural cycle (time of day)
Higher in the morning than in the evening
What is the order of structures seen on a nl gonio
I Cant See This Stupid Line Iris->Ciliary body-> S......->Trabecular meshwork->Swab Line
Which of the following immunoglobulins are not usually identified in the tear layer? IgA IgD IgG IgM
IgD
What components are NOT FOUND IN Aqueous
IgD, IgA, IgM (DAM they aren't here
Which immunoglobulin has the largest molecular structure? IgA sIgA IgG IgM
IgM
How does collagen changes affect aquo outflow
In POAG pts there is an accumulation of collagen in the aqueous humor (increase in collagen synthesis and decrease in collagen degradation)
How is Aqueous formation affected by reduced plasma osmolality like from drinking large quanities of water
Increase osmotic force in the ciliary epithelium
Accommodation cause an increase or decrease in outflow?
Increased accommodation=ciliary body muscles contract causes an increase in Trabecular outflow pathway Decrease accommodation= relaxation of the ciliary body muscles increase the UVEOSCLERAL outflow pathway Either way accommodation causes an INCREASE in OUTFLOW
How do glucocorticoids/steroids affect IOP
Increases amount of ECM in meshwork so increases IOP in some pts ie; Steroid responders
How is Aqueous formation affected by adrenaline/epinepherine?
It's treated like it reduces Aqueous production when the real mechanism is to increase outflow...overall it reduces IOP
What components are HIGHER in Aqueous than Plasma
Lactate Chloride Ascorbate Amino Acids Crystallin proteins from lens
A hypertonic tear film in a young adult is usually due to which of the following? Lipid deficiency Aqueous deficiency Excess chloride ions Excess potassium ions
Lipid deficiency
What substances can penetrate the blood aq barrier
Lipid soluble water water soluble (small, large proteins penetrate, regionally diff)
The loss of goblet cells in the bulbar conjunctiva results in which of the following? Increases the mucin layer of the tears Prolonged tear breakup time Normal spread of tears on the cornea Loss of tear film stability
Loss of tear film stability
What is the major and minor outflows of aqueous humor
Major=Trabecular outflow Minor=Uveoscleral outflow
Where does aqueous secretion RESISTANCE exist
Major=within Trab at Cribiform meshwork
What is Active Outward Transport
Movement of ions/molecules out of aqueous or vitreous back into the blood AGAINST a [grad] for example, large ions, iodide injected into eye towards thyroid, Prostaglandins
How does GAG's and Proteoglycans of Trab Meshwork affect aqueous outflow
NL juxtacanalicular tissue has hyaluronic acid as the main GAG. In POAG this tissue NL hyaluronic acid is replaced with ABNL chondroitin sulfate. This change leads to an increase outflow RESISTANCE and increased IOP
What 2 transporters are responsible for regulating pH
Na+/H+ exchangers Cl-/HCO3- exchangers these couple Cl- and Na+ influx
What is the driving force of aqueous production secretion and what enzyme determines its rate
Na+/K+ ATPase actively transporting Na rate dependent on Carbonic Anhydrase
Trabecular Meshwork cell volume in glaucomatous trabecular mesh cells is GREATER than nl cells b/c
Na+/K+/Cl- cotransport activity is REDUCED
What are the 2 components of Blood-Aqueous Barrier
Non-pig Epithelium of the ciliary body Iris Blood vessels (iris BV are sealed) (post., NPE BV are leaky=allow secretion of Aqueous but anterior, PE is less permeable)
Endothelial cells of the Trab Meshwork are phagocytic and help to clean the trabecular meshwork filter where aqueous humor "drains." With age the Trab endo cells decrease which leads to an increase in ECM. Because areas with MORE ECM are LESS PERFUSE (less holes for outflow) What does this Outflow obstruction lead to?
Primary Open Angle Glauc (POAG) caused by the "clogged-filter concept of glaucoma"
Which of the following tear film components does not exhibit antimicrobial properties Lysozyme Lactoferrin Complement Pyruvate
Pyruvate
Once on the surface of the conjunctiva, what is the function of the secretory portion of sIgA? Resists enzymatic degradation Acts as a receptor for helper T cells Binding IgA to the corneal epithelium Binding IgA molecules together
Resists enzymatic degradation
Heart relaxes (diastole)
Trab Mesh moves away from SC and fluid returns=decrease in Aqueous Vein Pressure
Heart contracts (systole)
Trab Mesh moves toward Sch. canal and pushes fluid out=increase Aqueous Vein Pressure
T/F Washout-associated increase in outflow faciltiy (capacity to drain fluid out) is an ACTIVE involvement of the Trab Meshwork in regulating outflow
True-the Trab Mesh is a LIVING, ACTIVE and REACTIVE TISSUE
Which process takes plasma through endothelial lining of the ciliary vasculature
Ultra-filtration
TQ?) Atropine induced ciliary body muscle relaxation causes
Unconventional (uveoscleral) outflow increase
The canal of Schlemm is drained primarily by external collector channels that lead into the a. deep scleral venous plexus b. palisades of Vogt c. superficial marginal plexus of the conjunctiva d. anterior ciliary veins e. central retinal vein
a
The canal of schlemm is drained primarily by external collector channels that lead into the a. Deep scleral venous plexus b. Palisades of vogt c. Superficial marginal plexus of the conjunctiva d. Anterior ciliary veins
a
Name 5 local (in the eye) factors that cause decrease in aqueous secretion
increase IOP by pseudofacility Uvitis Ret Detachment Retrobulbar anesthesia chorodial detachment
Beta 2 agonsit
increase trab outflow by TM disruption
Alpha 2
inhibits B-2 so decreases trab outflow and also reduces aqueous prod
Know 5 systemic factors that cause decrease in aqueous secretion
lower BP blowing nose (diencephalic stimulation) low body temp acidosis/decrease pH general anethesia
Which arm of aqueous production is pressure driven and which is not -diffusion -ultra-filtration -active secretion
pressure related= diffusion and ultra-filtration energy dependent= active secretion
Which of the following acts to limit microbial adherence to mucous membranes? Cysteine Integrons IgG sIgA IgE
sIgA
Which of the following tear film proteins DOES NOT increase secondary to reflex tearing? Lactoferrin Lysozyme sIgA Lipocalin
sIgA
What is the effect of epi on Trab outflow
somehow actin filaments of trab meshwork cells are broken (Beta2 receptors involved) which allows for an increase of outflow
What is the effect of epi on Aqueous Production
stimulates alpha and beta receptors. Beta 2 increases aqueous production while also increasing the outflow by disrupting ECM to increase trab outflow and relax ciliary muscle to increase Uveoscleral flow. But because
How does Epinpherine affect aqueous production
target's both alpha and Beta 2 receptors -Beta 2 causes both increase production and increase outflow *Trab Mesh outflow (disrupts ECM by making hole in it) and *Uveoscleral outflow (relaxing ciliary body muscle opens outflow pathway) alpha 2 inhibits Beta 2 production BUT over-riding effect is outflow is greater than production....therefore overall effect of epi is a decrease in IOP.
Which eye drops are CA inhibators
Dorzolamide and Brinzolamide
How many molecules of each ion is transported in the Na/K/Cl Cotransporter? Where is it located? What is it's function?
-1:1:2 ratio -located PE of ciliary bilayer more than on it's NPE layer -regulates volume of ciliary epithelial cells
Name 4 surgical factors that cause decrease in aqueous secretion
-cyclodialysis cyctocryothermy cyclodiathermy cyclophotocoagulation
Which of the following phrases best describes the energy requiring mechanism of aqueous humor secretion by the ciliary body? a. Pressure independent b. Pressure dependent c. Pressure dependence varies according to the intracellular bicarbonate balance d. Dependent on the intracellular pressure of the NPE cells
. Pressure independent
Name 4 main and 2 minor classes of drugs that cause decrease in aqueous secretion
1. Beta 2 ANTAGonist -olol 2. CA inhibators 3. alpha 2 AGONIST-onidine 4. Cardiac Glycosides 5. Adernergic AGONIST-epinepher 6. HYPERosmotic agents=Mannitol, glycerol and urea
Generally, how do prostaglandins affect aque outflow
1. relaxes ciliary muscle=increase UV outflow 2. Modifies ECM= increases degredation of collagen 3. incereases trab outflow=b/c there is an increase in cAMP
Explain the active involvement of Trab Meshwork in regulating aque. outflow
1.) TM is suspended btw 2 fluid compartments (Ant. Chamber and Schlemm's Canal) 2.) TM can "sense" pressure diff btw the 2 by "monitoring" movements like shear stretch, deformation, etc. 3.) Inside cells; Intergrins throughout the cell membranes connect OUTSIDE FIBRONECTIN of ECM to MICROFILLAMENTS OF CYCTOSKELETON INSIDE CELL. Any movement that causes stretch affecting fibronectin signals ECM to adjust by either relaxing or contracting. Therefore, these cells mediate the regulation of the ECM deposition
What are the 3 ways epinepherine affect outflow?
1.) decreases aqueous production 2. increases Trab outflow 3.) increases Uveoscleral outflow
What 3 factors modulate long-term homeostasis of aqueous secretion (?) in response to physical stress
1.)Cellular constituents 2.)Extracellular load-bearing constituents 3.)Water binding capacity of the GAG's
What is the main function of Aq. humor
1.)deliver O2 and nutrients like glucose and aa and to remove waste like CO2 and lactic acid from K and lens 2.) Maintain IOP 3.) Add to OPTICAL system of the eye 4.) Supply Ascorbic Acid antioxidant, absorb UV, regulate GAG's of Trab Meshwork 5.) Immune response to inflammation and infection
What is the production rate of aqueous formation?
2.5 mircoLiters/Min
What is the effect of epi on uveoscleral outflow
3.) Epi -stimulates prostaglandins synthesis which reduces IOP and -relaxes ciliary muscles to increase uveoscleral outflow
How long does it take for the basal tear to turn over 1-2 minutes 5-6 minutes 15 minutes 1 hour 2 hours
5-6 min
What is pseudofacility
A pressure sensitive decrease in production due to ultrafiltration BUT APPEARS as an increase in outflow Raised IOP may decrease blood flow in the ciliary body which may decrease secretion
Why is Pilocarpine used to treat high IOP
B/C the outflow through conventional, trabecular canal is greater than the resistance created at the unconventional uveoscleral canal. "Pilo=pokes" holes in TM to incease outflow
Drugs are made to address the "washout concept of perfusion-induced resistance" and "clogged-filter concept of glaucoma." What would such a drug target?
Basically, break up ECM to create more drainage holes which will INCREASE washout (increase outflow). ( I think)
Where is Na+/K+ ATPase found in regards to aqueous production
Basolateral side of NPE of ciliary body
Which of the following statements about vitreous are NOT true (pick 2) a. it is a metabolic respiratory center for metabolic waste b. the viscoelastic properties of vitreous makes it a shock absorber c. oxygen tension is highest in the central vitreous d. amino acids are higher in concentration in the anterior vitreous than in the posterior e. proteins are in higher concentration in the anterior vitreous than in the posteriorWhich of the following statements about vitreous are NOT true (pick 2)
C and E
Why is Carbonic Anhydrase improtant in aqueous production?
CA located on basal and lateral side of both PE and NPE. CO2 and H2O form CA, then dissociates into H+ and HCO3-. HCO3- is essential for ACTIVE SECRETION of aqueous humor secretion from NPE. -Inhibiting HCO3- which leads to inhibition of ACTIVE TRANSPORT of Na+ across NPE into first-formed aqueous...therefor reducing ACTIVE aqueous humor formation. -Inhibiting CA leads to decrease of HCO3- available for exchange with Cl- from cytosol of NPE to the aqueous also, decreases availability of H+ which decreases exhange of H+ and Na+ Therefore, inhibiting CA decreases Cl- and Na+ from entering PE and NPE which decreases the overall production of Aqueous production/secretion
What mucous layer can cover the trab meshwork and in narrow angles lead to decrease outflow
CMG=Cameral Mucous Gel which is a layer of glycoprotein-enriched hyaluronic acid
A tear supplement solution should contain all of the following EXCEPT Calcium Potassium Sodium Bicarbonate
Calcium
What is Secondary Aqueous
Change in aqueous composition due to disruption of B-A barrier. Injury=increase [protein]=flare
What is the primary source of IgA in the tear film? Lacrimal gland Accessory lacrimal glands Corneal epithelium Conjunctival vasculature
Conjunctival vasculature
Does aging cause an increase or decrease in outflow?
Decrease, with aging more GAGs of ECM hold onto water, filling in drainage holes of Trab Mesh causing RESISTANCE to outflow
How is Aqueous formation affected by hypothermia
Decreases formation. a drop in 7 degrees leads to about 50% reduction in secretion
What components are EQUAL in Aqueous than Plasma
Sodium=Same
As the eyelids close, the tears move in which of the following sequences? Superior/inferior fornix --> marginal strips --> lateral lacrimal lake --> marginal lacrimal lake Superior/inferior fornix --> lateral lacrimal lake --> marginal strips --> marginal lacrimal lake Superior/inferior fornix --> medial lacrimal lake --> marginal strips --> lateral lacrimal lake
Superior/inferior fornix --> lateral lacrimal lake --> marginal strips --> marginal lacrimal lake
Because ___________ antioxidant is reduced the trabecular meshwork will DECREASE with age.
Superoxide dismutase =antioxidant defense
describe the order of Pulsatile aque outflow
Systole= Left Venticle contracts and blood is pumped to choroid. Choroid volume increases causing IOP to increase as TM moves TOWARDS SC. SC narrow increasing pressure that pushes fluid into episcleral veins creating an Aqueous Pulse Wave that INCREASE Aqueous Vein Pressure during systole Diastole=Choroid volume decreases, IOP decreases TM moves away from SC Pressure falls causing Episcleral Vein Pressure to be higher than Aqueous Vein Pressure
T/F Integrin modulates ECM rigidity which modulates Cytoskeleton structure
T
T/F One possibility for dergangement in gluacoma is that the "set points (ratio of ECM to cellular components) become altered"
T
Which outflow pathway is dependent on pressure and which is independent of pressure/IOP
Uveoscleral outflow is the MINOR outflow and is INDEPENDENT ON IOP Trabecular outflow via Schlemm's Canal is the MAJOR outflow and is DEPENDENT ON IOP ( increase IOP=Increase OUTFLOW)
The progressive decrease in resistance is due to perfusion-induced washing away of extracellular material from the outflow pathway of tissue is known as?
Washout
Specifically, How do Prostaglandins PGF2a affect aqueous outflow
When TM is comprimised by inflammation debris accumulates. Prostaglandins INCREASE UVEOSCLERAL OUTFLOW which removes debris similar to how the lymph system would if the eye had one. reduces aqueous collagen remodels ECM increases UV outflow
How would an increase in episcleral venous pressure affect aqueous humor outflow? a. Resistance would increase b. Facility would increase c. Resistance would decrease d. Facility would be unchanged
a
Which of the following is correct regarding resistance to aqueous outflow? a. Increases with age b. Is a function of aqueous production c. Decreases with age d. Is increased in vascular hypertensives
a
What are the contributing components to the bloodaqueous barrier? (pick 2) a. Endothelial cells of the blood vessel in the iris b. Endothelial cells of the blood vessel in the ciliary process c. Nonpigmented epithelial cells of the ciliary process d. RPE cells e. Pigmented epithelial cells in the iris
a and c
Which of the following will cause an increase in the facility of aqueous outflow through the uveoscleral meshwork? (pick 2) a. Beta 2agonist b. Carbonic Anhydrase Inhibitor c. Hyaluronidase d. Prostaglandin analogue e. Glucocorticoid dexamethasone
a and d
Which of the following phrases correctly describe the active secretion process of aqueous humor production? (pick 2) a. Pressure independent b. Pressure dependent c. Pressure dependence varies according to the intracellular bicarbonate balance d. Dependent on the intracellular pressure of the NPE cells e. Consumes energy
a and e
How would an increase in episcleral venous pressure affect aqueous humor outflow? (pick 2) a. resistance would increase b. facility would increase c. resistance would decrease d. facility would be unchanged e. facility would be decreased
a and e (increase resistance/decrease outflow (facility)
Cholinergic Agonist (pilocarpine) increase aqueous outflow by
activating ciliary muscle contraction allowing for Trabecular outflow increase even though there is closing of the Uveoscleral canal causing increase outflow resistance. Overall outflow is greater than resistance
Name 3 general factors that cause decrease in aqueous secretion
age diurnal cycle exercise
What components are Lower in Aqueous than Plasma
albumin/globulin and other large proteins Lipids Glucose and Lactate (protein, fat, sugar)
Which of the following shortterm effects tend to decrease IOP? (pick 2) a. sitting up position b. brief exercise c. retinal detachment d. smoking marijuana e. supine position
all BUT e ???
Which of the following is needed for tear's proper distribution of wetting? Quality and composition of mucin Adequate fluid volume Sufficient blink frequency Good lid-to-cornea apposition All of the above
all of the above
What percent of aqueous chamber volumes is replaced per min in the -ant chamber -post chamber
ant chamber=1% post. chamber=3%
What effect will an IOP of 35 mmHg have on choroidal blood flow? (pick 1) a. no effect due to autoregulation b. flow will decrease c. flow will increase d. flow will fluctuate depending upon the time of day
b
Which of the following processes is the total production of aqueous humor NOT dependent on? a. The ultrafiltration of blood plasma from the capillaries of the ciliary processes b. Contraction of ciliary muscle fibers c. The osmotic flow of water secondary to the flow of electrolytes into the posterior chamber d. The active secretion from the nonpigmented epithelial cells e. Bicarbonate synthesis mediated by carbonic anhydrase
b
Which of the following will facilitate aqueous humor outflow through the trabecular meshwork? a. Relaxed ciliary muscle b. Contracted ciliary muscle c. Dilated pupil d. Prolonged steroid application
b
Which of the following is NOT true regarding the effect of aging on aqueous outflow and the trabecular meshwork? (pick 2) a. endothelial phagocytotic activity decreases b. the water binding capacity of the glycosaminoglycans decreases c. the facility of aqueous outflow increases d. the level of sulfation in the glycosaminoglycans increases e. the resistance of aqueous outflow decreases
b and c
Which of the following procedures are NOT involved in the production of aqueous humor? (pick 2) a. the ultrafiltration of blood plasma from the capillaries of the ciliary processes b. contraction of ciliary muscle fibers c. the osmotic flow of water secondary to the flow of electrolytes into the posterior chamber d. the active secretion from the pigmented epithelial cells e. bicarbonate synthesis mediated by carbonic anhydrase
b and d
12. Which of the following longterm factors is associated with higher IOP? (pick 2) a. small cuptodisc ratio b. female c. hyperopia d. American Indian e. African American
b and e
Secondary aqueous, compared to normal aqueous, has (pick 2) a. increased level of ascorbic acid b. increased level of protein c. decreased level of protein d. decreased level of lipids e. decreased level of ascorbic acid
b and e
Which of the following regarding the aqueous humor are NOT correct? (pick 2) a. is secreted from the ciliary nonpigmented epithelium in the pars plicata b. total turnover takes about a half hour c. low oxygen levels relative to the tear film d. low protein levels e. trace vitamin C levels
b and e
Which of the following will facilitate aqueous humor outflow through the trabecular meshwork? (pick 2) a. relaxed ciliary muscle b. contracted ciliary muscle c. pupil dilation d. prolonged steroid application e. pupil constriction
b and e (contraction and constriction)
What effect will an IOP of 35 mmHg have on choroidal blood flow? a. No effect due to autoregulation b. Flow will decrease c. Flow will increase d. Flow will fluctuate depending upon the time of day
b. Flow will decrease
In the lens, the concentration of which of the following ions is much higher than that in the aqueous humor? a. sodium b. magnesium c. potassium d. chloride e. calcium
c
Relative to IOP, what is the hydrostatic pressure in the suprachoroidal space? (pick 1) a. 24 mmHg higher than IOP b. equal to IOP c. 24 mmHg less than IOP d. 810 mmHg less than IOP
c
What is the primary source of amino acids and glucose for the cornea? a. limbal vessels b. tear layer c. aqueous humor d. lacrimal gland e. vitamin A
c
TQ?) Cholinergic agonist cause
ciliary muscle contraction leading to Conventional (trabecular) outflow increase
Which of the following is NOT true regarding the effect of aging on aqueous outflow and the trabecular meshwork? a. Endothelial phagocytic activity decreases b. The water binding capacity of the glycosaminoglycans increases c. The facility of aqueous outflow increases d. The level of sulfation in the glycosaminoglycans increases
c
Which of the following statements regarding the aqueous humor are correct? (pick 2) a. it is secreted from the ciliary body and the iris root b. aqueous humor turnover time is 5 hours c. it has a low level of protein d. is exposed to a high ambient oxygen tension relative to the tears e. leaves the eye largely via trabecular meshwork pathway
c and e
Which of the following would be MOST likely to cause an increase in the facility of aqueous outflow through the uveoscleral meshwork? a. Beta-blocker b. Carbonic anhydrase inhibitor c. Hyaluronidase d. Prostaglandin analogue
d. Prostaglandin analogue
How is Aqueous formation affected by age
decreases with age. after the age of 10 decreases by 3.2% every decade
Which process involves molecules that penetrate through PE to ACTIVE SITES on NPE where the ions enter from stromal side either by ______ or through gap junctions or by ________
diffusion through gap junctions or ion transport
Which of the following regarding the aqueous humor is not correct? a. Is secreted from the ciliary epithelium in the pars plicata b. Total turnover takes about 2 hours c. Low oxygen levels relative to the tear film d. Low proteins levels e. Trace vitamin C levels
e
