Flashcards in Exam 1 Koh- Cornea Biochem 2 Deck (98)
What are the types of collagen in the basal lamina?
4, 7, 9, 16
What 3 things are included in the basal lamina?
Collagen, fibronectin, Heparan sulfate
What proteoglycans are included in the stroma?
Keratan sulfate, dermatan sulfate, chondroitan sulfate
What types of collagen are in the stroma?
1 and 6 (major), 3 and 5 (minor)
What 3 things included in Descemet's membrane?
Collagen, laminin, fibronectin
What types of collagen are in Descemet's membrane?
4 and 8
What are MMPs?
A family of Zn2+ dependent enzymes
What do MMPs do?
Degrade ECM components (proteoglycans/collagens)
How many members of MMPs? What is found in a healthy cornea?
>26 members, only MMP2 found in healthy cornea
What MMPs are synthesized after corneal injury?
MMP1, MMP3 and MMP9
What is the physiological function of MMPs?
Neurite growth, cell migration, would healing, vessel growth, ovulation
What is the pathological function of MMPs?
Tumor growth and migration, fibrosis, glaucoma, arthritis, lupus, etc.
What are MMP substrates?
Most of the ECM components (fibronectin, vitronectin, laminin, entactin, tenascin, aggrecan, myelin, basic protein, etc.) and collagens (1, 2, 3, 4, 5,6, 7, 8, 9, 10, 14)
What are the tissue inhibitors of metallo proteinases?
TIMP 1-4, differentially expressed in tissues, and temporally follow the influx of MMPs, TIMP-2 is constitutively produced as is MMP-2
What are keratocytes?
Major cell type of the stroma and are involved in maintaining the ECM environment
What are some stromal problems?
Granular dystrophy, keratoepithelin (ECM, adhesion differentiation), lattice dystrophy, herpetic stromal keratitis
How think is Descemet's membrane?
~10 micrometers thick
What secreted Descemet's membrane?
What type of collagen is most abundant in Descemet's membrane?
What collagens are included in Descemet's membrane?
4, 5, 8, 9, 12
What is the function of Descemet's membrane?
Provides elasticity and deformability, imparts strength and resilience, the main resistance to normal intraocular pressure
What are 2 Descemet/Endothelial Problems?
Vogt's striae, decreased central corneal thickness
What type of cells are in the endothelium?
Polygonal cells 20 micometers in diameter
What is the cell density in the endothelium?
About 3000/ mm^2
What type of junctions are in the endothelium?
What do the pumps do in the endothelium?
Maintain a partially dehydrated state
What happens to the endothelium in aging?
Endothelial cells decreases with aging, a concomitant spreading and thinning of the remaining cells
Where is water pumped into?
What type of aquaporin is in the epithelium?