Basic Science Flashcards
What is the only cell type found in cartilage?
Chondrocytes
What is the most abundant component of articulate cartilage?
Water (60-80% of wet weight)
Collagen is composed of three alpha chains encoded by what gene?
COL2A1
What prevents pathologic degradation of collagen fibrils by collagenases such as MMP-1?
Aggrecan
How do the following change in osteoarthritis? Proteoglycan content | Keratan Sulfate | Chondroitin 4- sulfate?
Proteoglycan decreases
Keratan sulfate decreases
Chondroitin 4-sulfate increases
How do the following change with increasing age? Keratan Sulfate | Chondroitin 4- sulfate | Chondroitin 6-sulfate
Keratan sulfate increases
Chondroitin 4-sulfate decreases
Chondroitin 6 -sulfate remains the same
How does the density of collage, chondrocytes and water change with increasing depths of the articular cartilage zones?
They all decrease
***Proteoglycan content is strange where it is lowest in the superficial zone and highest in the deep zone
The cement line separates calcified cartilage from what?
Subchondral bone
What does BMP-2 do? How about BMP-7?
BMP 2 stimulates ECM synthesis | BMP-7 potentiates chondrogenic differentiation and decreases catabolic activity of IL-1 and MMP-1
How does water content change with aging and osteoarthritis in cartilage?
Water content decreases with age and increases with ostearthritis
Chondrocyte size increases and number decreases with what?
Increasing age, there is NO change with osteoarthritis
What is the normal coefficient of friction for a joint?
0.002-0.04
During routine knee arthroscopic procedures, what percentage of patients have evidence of articular cartilage injury?
60-65%
What size is considered a small cartilage defect that you can try with microfracture, OC autograft, or ACI?
< 2-4 cm 2
What cells produce hyaluronan and lubricin components in synovial fluid?
Type B Synovial cells (Fibroblast-like synoviocytes)
Viscosupplementation aims to temporarily replace what molecule in the joint?
Hyaluronic acid - provides shock absorbing effect in the joint and gives fluid non-newtonian properities
What is Hilton’s law?
joints are innervated by branches of the same nerves that supply muscles responsible for moving the joint
Further expanded by the Gardner observation that states the portion of the joint capsule that is tightened by a specific muscle group receives innervation from the same nerves that supply the antagonizing muscle group
All nerves are myelinated for what type and what is it for?
Type C and it is important for cutaneous pain, sympathic postganglionic, as a result conduction is the slowest
True or False: Spinal nerve roots have less perineurium than peripheral nerves and as a result are more susceptible to stretch and compression injuries?
True
What is the MOA of aspirin?
Cox inhibitor
What is the MOA of Warfarin?
Blocks vitamin K carboxylation in the liver so that factors 2, 7, 9, 10, protein C and S cannot be made. Stop 5 days preop
Antidote for warfarin?
Vitamin K and FFP
What is MOA of hepain?
Antithrombin III to inhibit Xa
Long tail binds plasma proteins and inhibits thombin IIa, IXa, XIa, XIIa
What is the antidote for heparin?
Protamin Sulfate
LMWH blocks what?
Xa and IIa
Antidote is protamine sulfate
What is the antidote for RIbaroxaban?
Andexanet (decody recominant factor Xa factor)
What is the antidote for Hirudins (Desirudin, Dabgitran)?
Idarucizumab (Praxbind)
aPCC
Vanadium is found in what metal alloy?
Titanium (Titanium 64 means 6% aluminum, 4% vanadium)
Nickel is found in what metals?
Cobalt-Chrome & Stainless Steel
Bacteria is most adherent to what metal? What about least adherent?
Most to titanium
Least to Tantalum
What corrosion happens at modular head neck junction?
Fretting
