Flashcards in Exam 1 Koh- Aqueous Humor 2 Deck (61)
What are the 3 outflow systems of the AH?
Corneoscleral meshwork, uveoscleral meshwork and episcleral vessels
What is the conventional outflow of the AH?
(65-90%) trabecular meshwork, Schlemm canal, collector vessels, intrascleral plexus, episcleral venous system
What is the uveoscleral outflow of the AH?
(Pressure insensitive) Pass across the face of ciliary muscle, into suprachoroid, and through scleral coat to end in the vortex system
What is the trabecular meshwork?
A specialized tissue at the chamber angle, is the major site for regulation of the normal bulk flow of the aqueous humor; superficial uveal meshwork, the deeper corneoscleral meshwork, and the juxtacanalicular connective tissue (JCT) adjacent to Schlemm's canal
How does the trabecular meshwork function?
Self-cleaning, unidirectional, pressure-sensitive, low- flow (2 micoliters/min/mmHg) biologic filter for the AH, and contributes thereby to control of the IOP
What is the trabecular meshwork outflow pathway?
Trabecular meshwork, Schlemm's canal, and the collector channels/aqueous veins
What is Schlemm's canal?
The inner wall endothelium, its basement membrane and the canal lumen
What are collector channels?
Collector channels and aqueous veins connect the canal lumen to the episcleral veins on the surface of the eye
How many collector channels are along the outerwall of Schlemm's canal?
What is the trabecular meshwork structure?
A lattice of connective tissue and endothelial cells embedded in GAG-like ground substance, then into the Schlemm canal and general venous circulation (episcleral vessels)
Why is there resistance in the trabecular meshwork?
In the vicinity of the inner wall endothelium of Schlemm's canal, its basement membrane, and the juxtacanalicular connective tissue
What are the tissue beams in the trabecular meshwork?
Or lamellae that have a core of collagenous and elastic fibers, and care covered by flat cells which rest on a basal lamina. The beams attach to one another in several layers and form a porous filter-like structure
What are the properties of the trabecular meshwork cells?
Have active phagocytic properties, high levels of cytoskeletal actin, lower levels of microtubules also contain vimetin and desmin = smooth muscle
Trabecular meshwork cells are specialized both for ______ transport of water and solutes and ______
Most of the matrix component in trabecular meshwork are synthesized and degraded by _______ cells
The phagocytic activity of TM cells is associated with what two things?
GAG-degrading enzymes and acid phosphatase
Each lamella or beam mostly contains what types of collagen?
1 and 3
The fine fibril contain what type of collagen?
The cells covering the trabecular meshwork beams is rich in collagen type ____ and ___
4 and laminin
The elastic fibers in collagen have a considerable amount of ____ ____ material
The spaces between the juxtaglomerular cells and extracellular maxtrix fibers contains what?
Ground substance, consisting of various proteoglycans and hyaluronan
What types of glycosaminoglycans (GAGs) are in the AH?
Hyaluronic acid, dermatan sulfate, and chondroitin sulfate
What are plaques?
Accumulation of extracellular matrix structures with age
What contributes to interstitial flow resistance?
Proteoglycans and GAGs
AH outflow resistance may be decreased by nearly 50% in bovine eyes after perfusion with _________
Secreted ECM proteins influence cell function by modulating ______ ______
What are the matrix proteins?
Elastin, fibronectin, versican, laminin, thrombospondin-1, SPARC (secreted protein, acidic and rich in cysteine), myocilin, optineurin
What 2 things are active in handling H2O2 and free radicals?
Catalase and a glutathione-dependent system
What is TGFb?
A member of a family of dimeric polypeptide growth factors