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Connective Tissue
CT
26
Physiology
Graduate
09/25/2008

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Cards

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