Osteoclast:Acellthat nibbles at and breaks downboneand is responsible for boneresorption.
Osteoclasts are large multinucleate cells (cells with more than onenucleus) that differentiate from another type of cell called amacrophage.
In正常的骨,骨形成和骨吸收基于“增大化现实”技术e closely coupled processes involved in the normal remodeling of bone. In osteoporosis, the net rate of bone resorption exceeds the rate of bone formation, resulting in a decrease in bone mass without a defect in bone mineralization. In women,osteoclastactivity is increased because of decreasedestrogenafter the menopause. (Men with prematurely decreasedtestosteronemay also have increased osteoclast activity.) These changes result in further net loss of bone. The amount of bone available for mechanical support of theskeletoneventually falls below the fracture threshold and one may suffer a fracture with little or notrauma.
The term "osteoclast" has a curious history. It was derived by putting osteo- (from the Greek osteon, bone) together with -clast (from the Greek klastos, broken). It was originally a surgical instrument used to fracture bones. The cell we call an osteoclast was then named an osotoclast to avoid confusing it with the surgical instrument. When the instrument became outmoded, the mantle of osteoclast fell upon the cell that resorbs bone.
