Term
| Fibrous CT generally contains what type of collagen? |
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Definition
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Term
| What adhesive glycoproteins would you find in Fibrous CT? In cartilage? In basement membrane? |
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Definition
Fibrous CT - Fibronectin
Cartilage- Chondronectin
Basement Memb.- Laminin |
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Term
| What type of collagen fibers would you most likely find in the basement membrane of endothelium? |
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Definition
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Term
| In a typical H&E stain, large areas of white space generally corresponds to what? |
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Definition
| White space corresponds to ground substance, which does not pick up stain (made of GAGs) |
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Term
| Collagen constitutes what percentage of overall body protein? |
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Definition
| Collagen makes up about 25% of total body protein |
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Term
| What is an important primary structural feature of all collagens? |
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Definition
Every third amino acid is a glycine [GLY] (Gly-x-y-Gly-x-y-Gly-x-y...)
Also, there is a high content of Proline and Lysine, which may be hydorxylated (which serve as a point of attachment for sugars) |
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Term
| What enzymes are required for hydroxylation of of collagen peptides? What cofactor do they require? |
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Definition
| Hydroxylation requires Prolylhyroxylase and lysylhydroxylase. They require vitamin C as a cofactor. (Which is why lack of vit. C causes scurvy) |
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Term
| Describe the secondary structure of collagen molecules. |
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Definition
| Collagen molecules are entirely helical, however they do NOT form alpha helixes. |
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Term
| Describe the quaternary structure of collagen. |
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Definition
| Collagen forms a trimer. It is hydroxylated in the ER, and activated when the ends of the procollagen precursors are cleaved off |
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Term
| How are fibrils of collagen molecules stabilized? |
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Definition
| They have lots of H-bonds and are covalently cross-linked |
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Term
| The disease caused by a defective type I collagen, where a single Gly become a Cys, is _________ |
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Definition
| Osteogenesis Imperfecta (causes brittle bones, multiple fractures) |
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Term
| Which disease is characterized by hypermobility of joints, due to poor cross linking of collagen fibers? |
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Definition
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Term
| Which cells create elastic fibers? |
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Definition
| Elastic fibers are created by fibroblasts (in loose CT), by smooth muscle cells of blood vessels, and by chondrocytes of elastic cartilage |
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Term
| Elastic fibers are composed of what three key proteins? |
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Definition
| Elastic fibers are composed of Elastin, Fibrillin and MAGP (microfibril associated glycoprotein) |
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Term
| What genetic disorder is associated with fibrillin protein? |
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Definition
| Marfan syndrome is related to fibrillin |
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Term
| Glycosaminoglycans (GAGs) are polysaccharides with repeating units of ___ and ___. They are all ____ charged. |
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Definition
1. monosaccharide A
2. monosacharide B
3. negatively |
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Term
| Most GAGs exist in the form of _________, in which the GAG is covalently attached to a poplypeptide called the ________ |
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Definition
1. proteoglycan
2. core protein |
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Term
| Proteoglycans form a proteoglycan aggregate by binding to _________ |
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Definition
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Term
| Because of their negative charges proteoglycans hold lots of water. Their ability to regulate fluid by reversable compressability is important for what mechanism? |
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Definition
| It allows for fluid exchange, which is important for allowing avascular tissue to obtain nutrients |
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Term
| Fibronectin is an example of an adhesive glycoprotein. What is its function? |
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Definition
| Fibronectin acts as a glue, linking the ECM to cell components. It has a collagen binding domain and a heparin binding domain |
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Term
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Definition
| Basal Lamina- the interface between a sheet of epithelial cells anchored to the underlying CT |
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Term
| What are 3 components of the Basal Lamina? |
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Definition
1) collagen (mostly type IV)
2) proteoglycans
3) adhesive glycoproteins |
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Term
| What composes the Lamina Reticularis? |
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Definition
| Primarily type III collagen and Fibronectin |
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Term
| What composes the basement membrane? |
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Definition
| Basement membrane is composed of the Lamina Reticularis and the Basal Lamina (it's a LM designation) |
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Term
| The external lamina corresponds to the basal lamina in which structures? |
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Definition
External lamina in:
1) muscle
2) adipose tissue
3) Schwann cells |
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Term
| What are the (3) functions of basal lamina? |
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Definition
1) attachment
2) barrier
3) regulate epithelial migration |
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