Tissues of MS system Flashcards
Glycoproteins are polypeptides that contain covalently linked \_\_\_\_\_\_? • Carbohydrates • Proteins • Proteoglycans • Collagen
Carbs
Which is true? The cells of the musculoskeletal system are predominantly of \_\_\_\_\_\_ origin? An exception to this is \_\_\_\_\_\_? • Mesoderm; nuchal ligament • Mesoderm; nucleus pulposus • Endoderm; nuchal ligament • Endoderm; nucleus pulposus
B Mesoderm, Nucleus pulposus (which is neuroectoderm/notochordal)
Which is true about collagen?
• Comprises 40% of the dry weight.
• The fibril-associated collagens assume a fibrillar structure.
• All collagens share a common tertiary structure, consisting of a triple helix made up of three separate polypeptide molecules called beta chains.
• Proline hydroxylation is an essential and primary rate-limiting step in collagen biosynthesis.
D is correct
A (90%)
B (do not - help fibrillar collagen form into 3D shapes)
C (alpha chains)
Which of the following statements is false?
• Aggrecan is a large proteoglycan that can be proteolytic enzyme aggrecanase
• Coacervation refers to the temperature-dependent alignment and macromolecule assembly of tropoelastin monomers
• Fibrillins are large, zinc-binding proteins that serve a structural role
• Elastin fibers can undergo deformation of approximately 70% of their resting length with a maximum extension of 220% before loss of strength
C (CALCIUM) binding proteins = fibrillins
Which of the following statements is true?
• Calciotropic hormones such as PTH and PTH-rp have largely indirect effects on the mobilization of Ca++ from bone
• The majority of collagen in bone is type III
• The organic component of bone is to resist compressive forces and the mineral component if to bear tensile stresses
• M-CSF and RANKL are major mediators of osteoblastic differentiation
A is true
B (wrong- type I)
C The organic component of bone is to bear tensile stresses and the mineral component is to resist compressive forces
D OSTEOCLASTIC differentiation for M-CSF and RANKL
Which of the following is true regarding articular cartilage?
A. The translucent appearance is due to the high water content of approximately 80%
B. Chondrocytes make up approximately 2 to 10% of articular cartilage by volume
C. Cartilage is subdivided into 3 unmineralized zones. The chondrocyte cell density increases going from Zone 1 to 3
D. Most of the collagen in articular cartilage is Type II, making up approximately 60-70% of the collagen content
B is true
What is the name of the line which delineates the unmineralized zones from the calcified cartilage?
Tidemark
Which of the following is false regarding the fibril architecture of articular cartilage?
A. The superficial zone undergoes tension parallel to the surface during joint compression
B. The deep and calcified zones a compressive state dominates, and the fibrils are perpendicular to the joint surface
C. The deep and calcified zones form a pre-stressed layer
D. The proteoglycan concentration increases with increasing depth and the collagen fibrils are more concentrated at the surface
C. FALSE
The superficial layer forms a pre-stressed, wear resistant protective diaphragm, with parallel/tangential to surface
The fibrils in the middle and deep zones are organized to withstand compressive loading
True/False
Fibrocartilage is rich in type 1 collagen with relatively small quantities of proteoglycans, compared to articular cartilage
True
_____ are a large and important class of ____ in which the CHO conjugates are unbranched polysaccharides containing amino sugars (glycosaminoglycans)
Proteoglycans
Glycoproteins
Define stress in regards to mechanical stimuli
force per unit area
Define strain in regards to mechanical stimuli
deformation in a given direction
Why is healing of tendon and ligament not effective?
fibrosis –> lack of adaptability of scar
inferior mechanical properties
Which of the following is not a function group for collagen classification?
a. fibril- forming
b. Heterotypic
c. Networking
d. Transmembrane
e. fibril-associated
B. Heterotypic is a structural grouping (V), along with homotypic (II, III) which has the same polypeptide alpha chains
Which of the following is NOT a step in collagen biopsynthesis?
a. Assembly of tropocollagen into macromolecular fibrillary complexes
b. O-linked glycosylation
c. Coacervation
d. Proline hydroxylation
C (coacervation for elastin and elastic fiber biosynth)
A = fibrillogenesis
