MUSCOLOSKELETAL SYSTEM: 38

Question 1

Where postnatal hematopoiesis predominantly takes place?

Answer 1

Long bones medullary cavity

Question 2

describe connective tissue

Answer 2

cells + fibers (hypocellular tissue), suspended in specialized extracellular matrix

Question 3

Why regenerated tendons and ligaments after rupture are inferior in mechanical strength?

Answer 3

Because regional connectiviy between cells is not effectively reestablished but only fibrosis between ends happen

Question 4

describe collagen structure (common tertiary structure)

Answer 4

triple helix made of three separate polypeptide molecules called alpha chains

Question 5

name factors contributing to collagen-rich tissues strength

Answer 5

-intrinsic mechanical properties of collagen

-orientation
-packing
-diameters of fibers

Question 6

name collagen arrangement in tendons and cartilage

Answer 6

tendons: parallel arrangement, dense packing

cartilage: web-like arrangement, smaller diameter

Question 7

proteoglycans structure

Answer 7

core protein with one or more glycosaminoclycan side-chain

Question 8

Matrix metallo proteinases:
a) cleave the intercellular bond?
b) cleave the extracellular matrix proteins

Answer 8

B

Question 9

formation of elastin require: …

Answer 9

presence of both FIBRILLINS and FIBRONECTIN

Question 10

elastic fibers yield point and rupture

Answer 10

70% until plastic deformation, 220% loss of strength

Question 11

what are the main substances present in the extracellular matrix of connective tissue?

Answer 11

nonfibrillary proteins, glycoproteins, proteoglycans, proteolipids (collagen)

Question 12

main collagen contained in extracellular matrix of periosteum

Answer 12

collagen tye 1, along with proteoglycans and appreciable quantity of elastin

Question 13

bone percentage composition

Answer 13

70% mineral
5-10% water
Collagen is 90% of organic percentage

Question 14

common collagen in bones

Answer 14

type 1

Question 15

name the law that dictates that bone remodel adaptively in response to mechanical load

Answer 15

wolff’s law

Question 16

name the law for growth cartilage grow related to load

Answer 16

heuter-volkmann law

Question 17

cartilage percentage composition

Answer 17

70% water

Question 18

most common collagen in articular cartilage

Answer 18

type 2

Question 19

how many zones can be identified in articular cartilage?

Answer 19

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

Question 20

What is the main material that forms following heal of degenerated bones, ligament, cartilage…

Answer 20

fibrocartilage

Question 21

name 3 differences between fibrocartilage and cartilage

Answer 21

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)

Question 22

main collagen in tendons

Answer 22

type 1

Question 23

what is the viscoelastic property of a tendon or ligament

Answer 23

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

Question 24

name the dense bands of collagen of a tendon that merges with the periosteal membrane

Answer 24

Sharpey’s fibers

Question 25

differences between fibrous and fibrocartilaginous enthuses

Answer 25

fibrous: predominate between tendon and diaphyseal bone
fibrocartilagineous: between tendons and apophyseal or metaphyseal

Question 26

after avulsion of a fibrocartilagineous enthuses, reattaching a tendon results in:
a) fibrous entheses only
b) reestablishment of a fibrouscartilagineous entheses

Answer 26

B