MUSCOLOSKELETAL SYSTEM: 38 Flashcards
Where postnatal hematopoiesis predominantly takes place?
Long bones medullary cavity
describe connective tissue
cells + fibers (hypocellular tissue), suspended in specialized extracellular matrix
Why regenerated tendons and ligaments after rupture are inferior in mechanical strength?
Because regional connectiviy between cells is not effectively reestablished but only fibrosis between ends happen
describe collagen structure (common tertiary structure)
triple helix made of three separate polypeptide molecules called alpha chains
name factors contributing to collagen-rich tissues strength
-intrinsic mechanical properties of collagen
-orientation
-packing
-diameters of fibers
name collagen arrangement in tendons and cartilage
tendons: parallel arrangement, dense packing
cartilage: web-like arrangement, smaller diameter
proteoglycans structure
core protein with one or more glycosaminoclycan side-chain
Matrix metallo proteinases:
a) cleave the intercellular bond?
b) cleave the extracellular matrix proteins
B
formation of elastin require: …
presence of both FIBRILLINS and FIBRONECTIN
elastic fibers yield point and rupture
70% until plastic deformation, 220% loss of strength
what are the main substances present in the extracellular matrix of connective tissue?
nonfibrillary proteins, glycoproteins, proteoglycans, proteolipids (collagen)
main collagen contained in extracellular matrix of periosteum
collagen tye 1, along with proteoglycans and appreciable quantity of elastin
bone percentage composition
70% mineral
5-10% water
Collagen is 90% of organic percentage
common collagen in bones
type 1
name the law that dictates that bone remodel adaptively in response to mechanical load
wolff’s law
name the law for growth cartilage grow related to load
heuter-volkmann law
cartilage percentage composition
70% water
most common collagen in articular cartilage
type 2
how many zones can be identified in articular cartilage?
1) superficial zone: collagen fibrils parallel to joint
2) transitional zone: three dimensional ortientation, larger fibers perpendicular to surface
3) radiate zone, larger cells, perpendicular, some are mineralized
What is the main material that forms following heal of degenerated bones, ligament, cartilage…
fibrocartilage
name 3 differences between fibrocartilage and cartilage
1) majority of collagen type 1 in fibrocartilage
2) collagen fibers oriented largely on load direction
3) fibrocartilage has small quantities of proteoglicans (cartilage 35% of organic matter)
main collagen in tendons
type 1
what is the viscoelastic property of a tendon or ligament
the rate of loading affects the response:
-STRESS RELAXATION (decrease in stress under long period of strain) and -CREEP (slow deformation while maintaining stress for long periods) can occur at low load over long periods of time
name the dense bands of collagen of a tendon that merges with the periosteal membrane
Sharpey’s fibers
differences between fibrous and fibrocartilaginous enthuses
fibrous: predominate between tendon and diaphyseal bone
fibrocartilagineous: between tendons and apophyseal or metaphyseal
after avulsion of a fibrocartilagineous enthuses, reattaching a tendon results in:
a) fibrous entheses only
b) reestablishment of a fibrouscartilagineous entheses
B
