Disuse osteoporosis may be focal, involving a single bone or limb (arthritis or limb immobilization), or it may be generalized (prolonged bed rest or paralysis). With generalized immobilization, bone loss…
An intricate physiologic mechanism has evolved to prevent dangerous hypocalcemia: a reduction in calcium intake stimulates calcium absorption by the gastrointestinal tract, promotes renal calcium conservation, and stimulates net bone…
1. Calcium phosphate is minimally soluble in water. In fact, at the pH of body fluids and the concentrations of calcium and phosphate ions found in extracellular fluids, the critical…
Example 7 shows the highly uncoupled state of increased bone formation and decreased bone resorption that result in a net increase in bone mass. Such a state of remodeling is…
Unless a significant metabolic insult occurs to bone early in life, the peak adult bone mass will exceed the threshold for spontaneous fracture. Noninvasive techniques to measure bone density have…
Calcium Requirements. The body regulates few functions with greater fidelity than the concentration of ionized calcium in the extracellular fluid. Although extracellular calcium represents less than 1% of the body’s…
The exchange of calcium between extracellular fluid and bone can be considered kinetically (see Plate 2-28). Through a slow phase of bone formation and resorption, approximately 1000 mg/day of calcium…
Regardless of its histologic type, connective tissue is made up of two components, cells and extracellular matrix. Fibroblasts (which synthesize collagen), fat cells, fixed macrophages, mast cells, plasma cells, and…
On gross examination, the synovial surface appears pale pink and shiny. Although some folds can be seen with the naked eye, the characteristic villi that increase the effective surface area…
To make the situation even more complex, aggrecans form aggregates with two other matrix components—hyaluronan and link proteins. This aggregate consists of a variable number of proteoglycan monomers, depending on…
