Trabecular meshwork and aqueous outflow Flashcards
AC mean depth is? horizontal diameter of AC? Vertical diameter was?
3.64mm
12.20mm
vertical larger than horizontal by about 100 um
aqueous humor fills what part of the eye? supports metabolic needs of avascular tissues such as?
anterior segment (clear nutritive fluid) lens, cornea and TM
aqueous humor is secreted by what? at what rate?
ciliary body at a rate of 2.5ul per min. amount produced must equal amount drained.
pathway of aqueous humor from schawlbes line to ciliary body band?
schawlbes line (where decemets ends and TM starts) -> schlemms canal ->TM ->sceral spur (posterior region of TM) ->ciliary body band
What is the conventional outflow pathway of aqueous humor starting with aqueous humor and ending with venous system?
aqueous humor, uveal meshwork, corneoscleral meshwork (anterior TM), juxtacanalicular meshwork (JCT), schlemms canal, collector channels, deep scleral plexus, intrascleral plexus, episcleral veins and then venous system.
in the aqueous outflow pathway what two types of regions are there?
non filtering (anterior) and filtering (posterior, lots of pigment here compared to anterior).
the five layers found in a normal open angle in goniophotograph view are?
- schawlbes line
2/3. two layers of TM - scleral spur
- ciliary body band
scleral spur is a point of attachment for which muscles?
longitudinal bundle of CM
schawlbes line is a peripheral terminus of which corneal layer?
decemets.
what percent of aqueous humor flows out through TM path? what does other percent do?
80% out of TM path
other 20% goes through uveal path or non conventional
What is the issue with the spacing between the uveal meshwork and cornealscleral meshwork? however as we get closer to what, what happens?
interlamellar spaces are too large to generate significant resistance.
as we get closer to schlemms canal, spacing becomes smaller therefore generating resistance.
Principle pressure drop is what and occurs where? therefore, this indicates that the most probable location of the majority of outflow resistance in the normal eye is where?
7-14um of inner wall of schlemms canal.
JCT region and/or inner wall of schlemms canal.
when the CM contracts, what does this cause?
opening of TM and schlemms canal to allow outflow.
On the inner wall endothelial cells of schlemms canal what are two unique aspects?
giant vacoules (outpouchings) and pores. there are two types of pores which are intracellular (I pores) and paracellular or border pores (B pores)
the giant vacoules in the inner wall of schlemms can form how? these vacoules are dependent on what?
by one cell or two cells fusing together.
pressure (not found unless inner wall is fixed under conditions of flow).
How does the aqueous humor pass through the inner wall of schlemms?
JCT, giant vacoule, pore then canal.
In the inner wall of schlemms, where are b pores found? i pores?
B pores always found between two cells
I pores found in just one cell.
In glaucoma, how does this affect the number of pores found in inner wall of schlemms?
in glaucoma, we see that the pores are reduced allowing for pressure build up.
is aqueous outflow uniform?
NO, only a fraction of JCT TM and inner wall of schlemms are active in filtration at any given time.
normal pressure in an anucleate eye? what was found with increasing IOP?
7mmHg
schelmms canal became narrower, JCT and inner wall were pushed into collector channels therefore confining flow to a smaller area.
how many collector channels per eye? where and how are they distributed?
+/- 30
unevenly distrbuted throughout schlemms.
which TM is closest to AC?
uveal TM