Osteoclast Coefficient Of Bone Mineral Density For Quantum Resonance Magnetic Analyzer:

Osteoclast consists of multinuclear giant cells that reach a diameter of 100|¨¬m, contain 2 ~ 50 nuclei and are mainly distributed in the bone surface and around bone vascular access. The osteoclasts whose number is less are combined by several single-nucleated cells, the basophilia of cytoplasm is aged following with the cells to be gradually changed to be eosinophilic.

Osteoclast has a special absorption function. In absorbing some local inflammatory lesions, macrophages are also involved in the process of bone resorption. In the process of osteoclasts absorbing organic matters and mineral in bone matrix, the surface of matrix becomes irregular to form lacuna in a similar shape of cells, and the lacuna is called as howship. On the side toward the bone in the howship, the cells protrude a lot of hair-like protrusions which are like the longitudinal profile border and the brush border of the surface of epithelial cells. Under the electron microscope, one side close to the bone has many irregular microvilli, namely cell protrusions, being called as ruffled border. There is a circular cytoplasmic zone on the periphery of the ruffled border zone. The cytoplasmic zone contains some microfilament but lacks of other organelles, being known as clear zone where the cell membrane is smooth and is close to the bone surface. The clear zone is like a bounding wall consisting of cytoplasm and makes the surrounded area form a micro-environment. Osteoclast releases lactic acids, citric acids and others to the part. Under the acidic condition, the bone inorganic minerals are in pinocytosis from the ruffled border to form some pinocytotic vesicles or phagosomes in ruffled border matrix. In the osteoclast, the inorganic objects are degraded to be expelled into the blood stream in the form of calcium ions. The loss of inorganic objects makes collagen fibers in the bone matrix exposed. Osteoclast secretes a variety of lysosomal enzymes, especially cathepsin B and collagenolytic cathepsin. After osteoclasts leave from the bone surface, the ruffled border disappears, and the inner parts of cells are changed to enter the stationary phase. Mononuclear cells in blood or phagocytic cells in tissues can not be transformed into osteoclasts, because all these cells only contain mature, unsplit and late mononuclear phagocytes. Only the early immature proliferating mononuclear phagocytes are the precursors of osteoclasts.