Where are collagen fibers located? What gives a collagen fiber it's characteristics?
Collagen fibers are dispersed in the ECM. The amount of fibers present and the proportions of fibers specialize CT
what are collagen fibers made of?
polymer of collagen fiber bundles. Each individual fiber in the bundle is made of collagen fibrils, each fibril is a sequence of tropocollagen molecules bound together. Tropocollagen is produced from procollagen
what kind of types of collagen fibers are there and what type of resistance do they provide?
more than 25 types, type I, II, III, IV are most common
provides resistance to tensile forces
type I collagen
strongest, largest, most abundant type
type II collagen fibers
found in articular cartilage and fibrocartilage
type III collagen fibers
synonymous with reticular fibers, found in skin, artery wall, initially scar tissue
Type IV collagen
major filament of basement membranes (basal lamina)
type III collagen, small diameter and loosely arranged (flexible for volume changing organs)
smooth muscle, endoneurium, hematopoietic organs, papillary layer of dermis
where do elastin polymers aggregate in the elastin fiber?
in the center, with oxytalan and elaunin on the outside
what is elaunin?
Elaunin is a mixture of elastin protein and oxytalan fibers (a component of elastin fibers)
what is oxytalan?
oxytalan is a component of elastin fibers. It is the non-elastic component that is situated on the outside of the fiber
what are glycoproteins? what are their function?
Proteins that adhere to cell membranes that, along with proteoglycans, make ECM more rigid and structural. Laminin and fibronectin are examples
What are glycosaminoglycans? What are their function?
they are polysaccharide chains containing amino sugars that are a branching component of proteoglycans. They help to give the ECM more structure/make it more viscous
loose CT: what does it support?
tissues that are not subjected to much friction, under low pressure
flexible well vascularized, not resistant to tensile forces, many fibroblasts and collagen
resistance to tensile forces and protection of tissues
fewer cells, more fibers
arranged into regular (unidirectional) and irregular types (multidirectional)
ligaments of spinal column, contains parallel elastic fibers with collagen interspersed
loose CT built by specialized fibroblasts, spongy so as to allow passage of materials/cells