Lecture 7: Connective Tissue (Hayward) Flashcards
main type of connective tissue in the MS system*
dense connective tissue (esp. dense REGULAR CT)
2 main classifications of connective tissue*
ordinary and specialized CT
“ordinary” CT consists of what 2 types of CT?*
loose and dense CT
“specialized” CT includes:*
cartilage and bone
2 types of dense CT*
regular and irregular CT
difference b/w loose and dense CT*
dense CT has larger # of fibers compared to # of cells
characteristics of regular dense CT*
parallel bundles of fibers. Present in tendons, ligaments, and aponeurosis
chars. of irregular dense CT*
Allow more stretch and distension than regular dense CT. Present in dermis, submucosa of digestive tract, and fascia.
3 types of fibers secreted by fibroblasts*
collagen, elastic fibers, reticular fibers
role of amorphous ground substance in connective tissue**
imparts “spongyness” and capacity of connective tissue to take on compressive forces. Its negative charge draws Na+ and subsequently H2O towards it, giving it a characteristic gel-like property. Common in loose connective tissue
which are more active: fibroblasts or fibrocytes?*
fibroblasts; they are actively producing intercellular fibers
role of reticular fibers*
act as supportive meshwork/anchoring system between collagen and adjacent cells in the lamina
general role of tendons and ligaments*
absorb stretching forces
why does collagen have a banded appearance at light microscopic lvl?*
due to interconnection of individual filaments
type 1 collagen fibers are present in:*
tendons, ligaments, bone, and fibrocartilage,
type 2 collagen fibers are present in what type of connective tissue?*
Hyaline and elastic cartilage. (i.e. intervertebral discs)
type 3 collagen fibers are present in:*
loose connective tissues, reticular fibers, blood vessels
what are reticular fibers composed of?*
type III collagen with polysaccharide coating in a basal lamina
How are elastic fibers able to undergo expansion and recoil?*
They have strong interfiber crosslinking which is mediated by LYSYL OXIDASE. They also automatically recoil when they don’t have any stretch on them.
what are elastic fibers composed of?*
elastin and fibrillin
role of fibrillin in elastic fiber composition*
help mold elastin molecules into elastic fibers
Marfan’s syndrome*
a deficiency or defect in fibrillin. Leads to underdevelopment of elastin. Patient is predisposed to aortic rupture and joint instability
Composition of amorphous ground substance**
glycosaminoglycans and proteoglycan. Has high neg. charge which attracts Na+ and thus H2O into it. High negative charge of GAGs imparts compressive strength to connective tissue**
what is basal lamina? What is it composed of?
interface between conncective tissue and adjacent layer. Composed of type 4 and 7 collagen, laminin (which binds cell membrane to collagen and proteoglycans of laminae), and fibronectin (which attaches cell to basal laminae)