Ch 19 ID Terms

Secretes matrix macromolecules in most connective tissues

• In connective tissue, they form a hydrated, gel-like “ground substance” in which the fibrous proteins are embedded; the polysaccharide gel resists compressive forces on the matrix while permitting the rapid diffusion of nutrients, metabolites, and hormones between the blood and the tissue cells
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• They can be huge.

strengthen and help organize the matrix

ex: elastin--give resilience

• Unbranched polysaccharide chains composed of repeating disaccharide units; GAGs: one of the two sugars in the repeating disaccharide is always an amino sugar (N-acetylglucosamine or N-acetylgalactosamne); the second sugar is usually a uronic acid (glucuronic or iduronic)
• Highly negatively charged; they are the most anionic molecules produced by animal cells

Simplest of the GAGs, consisting o fa regular repeating sequence of up to 25,000 disaccharide units; found in variable amounts in all tissues and fluids in adult tissues, and is especially abundant in early embryos

Stimulate a variety of cell types to proliferate; this interaction oligomerizes the growth factor molecules, enabling them to crosss-link and activate their cell-surface receptors, which are transmembrane tyrosine kinases; heparin sulfate chains of proteoglycans bind to it

Heparin sulfate proteoglycans immobilize secreted chemotactic attractants called these on the endothelial surface of a blood vessel at an inflammatory site, allwing chemokines ot remain there for a long period, stimulating white blood cells to leave the bloodstream and migrate into the inflamed tissue

Membrane-spanning core protein whose intracellular domain is thought to interact with the actin cytoskeleton and with signaling molecules int eh cell cortex; located on the surface of many types of cells, including fibroblasts and epithelial cells

syndecans can be found in cell-matrix adhesions, where they modulate integrin function by interacting with fibronectin on the cell surface and with cytoskeletal and signaling proteins inside the cell; also bind FGFs and present them to FGF receptor proteins on the same cell.

A family of fibrous proteins found in all multicellular animals; secreted in large quantities by connective tissue cells, and in smaller quantities by many other cell types; most abundant protiens in mammals

Type I; long ropelike structures with few or no interruptions; after being secreted into the ECS, these collagen molecules assemble into higher-order polymers called collagen fibrils, which are thin structures many hundreds of micrometers long in mature tissues

Types IX and XII; decorate the surface of collagen fibrils; link fibrils to one another and to other components of the ECM

A network of these in the ECM gives tissues the required resilience so that they can recoil after transient stretch

A highly hydrophobic protein which is unusually rich in proline and glycine but, unlike collagen, is not glycosylated and contains some hydroxyproline but no hydroxylysine.

inactive protease precursor that is abundant in the blood

cleave plasminogen locally to yield the active serine protease plasmin, which helps break up blood clots