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Unformatted text preview: Articulations or Joints Bones are connected to each other by joints. The most common joint type is the diarthrosis of articulating joints, which has a fibrous connective tissue capsule ( ligament ), continuous with the periosteum of the two bones and which permits a degree of freedom of movement between the two bones. The inner part of the capsule consists of the synovial membrane , which may extend as a fold ( synovial fold ). The synovial membrane is well vascularised with both blood and lymph vessels. The main cell type present in the synovial membrane, are fibroblast-like cells, and involved in the formation of the synovial fluid . This fluid is rich in hyaluronic acid and fills the joint cavity. Macrophage-like cells are also found in the synovial membrane and are responsible for keeping the synovial fluid clean and free of cell fragments. The synovial fluid plays an important role in the lubrication of the joint and in providing nutrition for the articular cartilage of the epiphyses. Fat deposits or pads, found between the synovial membrane and the ligament, function as mechanical shock absorbers. Aging changes to joints, in particular pathological changes of the articular cartilage ( osteoarthritis ), are very common in the elderly. Function together Hold skeleton Provide mobility Weakest part of the skeleton FIBROCARTILAGE ibrocartilage is found in areas of the body subject to high mechanical stress or weightbearing. It ) intervertebral disks r joints nts to bones Fibrocartilage is characterized by large numbers and concentrations of collagen fibers in the by he intervertebral disks consist of fibrocartilage plates between the vertebrae and act as ) the annulus fibrosus , which is the outer region consisting of orderly concentric b) the nucleus pulposus (large vacuolated cells, that are vestiges of the F lacks the flexibility of the other cartilage types. Fibrocartilage is present in: (a (b) pubic symphysis (c) temporo-mandibula (d) at sites of connection of many ligame (e.g. Ligamentum teres femoris ) (e) tendon insertions. matrix. These collagen fibers are the dominant feature of the matrix and with relatively little amorphous matrix. The large amounts of collagen fibers result in the matrix appearing acidophilic in histological sections after H&E staining. Fibrocartilage is not surrounded perichondrium. T mechanical shock absorbers. In sections they are seen to be formed of two components: (a arrangements of cells and matrix dominated by type I collagen (as in tendons) ( embryonic notochord. Two main functional groups of joints ynovial (NL; between oval surfaces)= diarthroses (Gk. to fasten by a joint): extensive synovium: specialized layer of collagenous tissue lining inner aspect of capsule; inner s movement at articular surfaces; maintained in apposition by fibrous capsule and ligaments; surfaces lubricated by synovial fluid surface discontinuous layer cells up to four synovial cells deep; no junctional complexes or basement membrane; mesenchymal origin; type A synovocytes: plump, majority;...
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This note was uploaded on 10/18/2010 for the course BIO 2402 taught by Professor Opara during the Spring '10 term at Lone Star College.
- Spring '10