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27 Cards in this Set
- Front
- Back
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where is hyaline cartilage?
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- AC
- RT - physis - costal C - fetal skeleton |
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why is AC hyaline cartilage special?
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- it has lacunae that house chondrocytes
- superficial are flat w/ 1 chondrocyte - deep are round w/ at least 2 |
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elastic cartilage
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- Permeated with elastin fibers - Confers resiliency
- External Ear, Walls of EAM and auditory tube - Arytnoid cartilages and epiglottis |
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fibrocartilage
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- no perichondrium
- thick collagenous fibers w/ limited matrix - Ligaments, Certain tendons - Symphyseal joints: IV dick - Articular discs: Meniscus - hyaline cartilage turns into this w/ aging |
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when do superficial zones of AC calcify?
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only in pseudogout
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where does AC get its nourishment?
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synovium
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whats the deal w/ cartilage and the TMJ?
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- TMJ has is formed by intermembranous ossification
- so its AC is made of fibrocartilage |
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Type A synovial cells
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- resemble macrophages
- prominent surface ruffling w/ lysosomes & smooth-walled vesicles |
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Type B synovial cells
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- secretory (fibroblast-like) cells w/ abundant RER
- likely source of lubricin and hyaluronic acid in synovial fluid |
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fibrous synovial membrane
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- lies right on capsular ligament
- over intraarticular ligament and tendons - where synovium subject to pressure |
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areolar synovial membrane
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- loosely bound to capsular ligament
- places where it must move freely, lik suprapatellar pouch of the knee joint |
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adipose synovial membrane
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- covers intrarticular fat pads
- olecrenon fossa |
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Pericellular Matrix
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- Thin rim surrounding the cell (varies with disease)
- Fewer type II fibrils, mostly type VI and proteoglycans - Transmembrane proteins for mechanical signals |
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Territorial Matrix
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- Envelops the cell and the pericellular matrix
- More collagen fibrils, mostly small diameter - Protects the cell from injury? |
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Interterritorial Matrix
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- Largest matrix region by volume
- Large diameter collagen fibrils - Responsible for major mechanical properties of cartilage |
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Type XI collagen
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- forms fibrils with type II
- thought to influence type II fibril diameter |
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Type IX collagen
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- found on the surface of type II
- may organize and stabilize the overall meshwork |
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Aggrecan
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- dominant form of proteoglycan of collagen
- Combines w/ hyaluronan to form large aggregates of multiple proteoglycan molecules - “Bottle brush appearance |
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what is the function of the collagen matrix?
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- prevents molecules from swelling to full volume
- Matrix is always pressurized - the collagen molecules are trapping proteoglycan molecules in the matrix to a smaller volume than they would be (what gives us elasticity) - Lets cartilage resist compression |
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Collagenase
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- MMP-1, 13
- cleaves type II |
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Stromelysin
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- MMP-3
- cleaves type IX and XI collagens, aggrecan, and other small proteoglycans |
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Aggrecanase
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- this and and some MMPs cleave proteoglycan
- Loss of aggrecan - Loss of “bound” water - Loss of function |
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stickler syndrome
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- genetic defects in type II and XI collagen
- premature development of osteoarthritis |
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Boundary lubrication
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- surface of cartilage binds lubricin
- for low velocity |
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Hydrodynamic lubrication
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- exuded water film
- for high velocity |
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what is in the synovium?
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- Lower protein, higher albumin
- Hyaluronan, phospholipids, glycoproteins (from B synoviocytes) - AP (from chondrocytes) - Plasminogen to recude clot formation (from synovium and cartilage) |
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how does synovial fluid change in arthritis?
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- increased volume
- goes from clear to yellow - increased opacity - decreased viscosity |
