11/17 Histo of Cartilage Flashcards
(54 cards)
what are the tree types of cartilage
hyalin cartilage; elastic cartilage; fibrocartilage.
How is Cartilage different from CT proper?
Avascular; only one cell type peresent, the chondrocyte. Type II collagen present
Compare the Cells in CT proper and Cartilage
CT: (Fibroblasts, adipocytes, MOs, Mast cells, Lys, Plasma cells, granulocytes. Cartilage (Chondrocytes)
compare the fibers in CT proper and Cartilage
CT Proper ( Type I collagen, some type III, elastic variables) Cartilage (type II collagen, type i varies elastic variable)
Compare the Ground substance of CT proper and cartilage
- Both have lots of GAGs. 2. Both have lots of proteoglycans (Cartilage has lots of aggrecan found in hyaline.) 3. Adhesive glycoproteins: CT proper(fibronectin, laminin). Cartilage (chondronectin, as well as fibronectin and laminin.)
What is the stem cell origin of cartilage.
they are from mesenchymal stem cells.
What is collagen?
it is a family of proteins, ca. 30 different genes with about 25 different types of collagen but 90% of it is Type I
Describe Type I collagen
Helix of 3 alpha chains (alpha 1 and alpha 2): 33% glycine (about every 3rd residue) with proline and lysine that is made into prolyl hydroxylase and lysyl hydroxylase.
What is the neccessary component that is needed to make the hydroxylases out of proline and lysine to make collagen (proline and lysine hydroxylation)?
vitamin C and oxygen in order to perform the hydroxylase reaction with proline and lysine
How does the reaction that is usd to make collagen used to control oxygen?
the reaction with vitamin C to make the hydroxylates also uses oxygen and so it can be a mechanism for sensing normoxia and hypoxia
What is the general chemical reaction that is needed to use amino acids to make collagen?
hydroxylation!
What if I don’t ever eat Vit. C what will happen
scurvy (general weakness, skin lesions, blood vessels fragility) where I can’t do hydroxylation of amin acid and cant make collagen.
Describe the construction of Collagen I fibers..
Tropocollagen is packed into overlaping layers that make alpha chains that are then wrapped together into fibrils, and then these are packed into fibers, and fibers are packed into bundles that make up structures such as tendons
How is Type II collagen structure different from type I?
it has tropocollagen layered into tropocollagen sheets that is wrapped into triples of alpha chains that are packed together to make fibrils (just like type I). Type II then stays as a fine mesh like structure of fibrils
How is type III different from Type I collagen construction
Associates into Fibers but not into bundles.
what gives hyaline cartilage matrix its high tensile strength and resiliency?
huge proteoglycan aggregates bind a considerable amount of water and ions, giving the matrix these properties.
the most widely dist. cartilage in the body
Hyaline cartilage
Hyaline cartilage found in…?
walls of large respiratory passages; larynx; articular surfaces of bones; ventral ends of ribs
Transient location of hyalin cartilage
model of skeleton, epiphyseal growth plate
Why would hyaline cartilage appear glassy and be strong and smooth?
it is type II collegen that is not fibers by a highly hydrated matrix!
Describe the contents of the Hyaline cartilage matrix
The proteoglycan aggregates, GAGs and Proteoglycans (e.g. AGGRECAN) along with: Bound water; and Type II collagen fibrils; and chondronectin that attaches cells to ECM, and finally Chondrocytes that turnover and replace matrix.
how much of the wieght of the hyaline cartilage would be water?
75-80%
What is the main fiber in hyaline cartilage matrix
Type II collagen fibrils (40-70% dry weight)
Attaches the cells to ECM in Hyaline cartilage…?
Chondronectin
