Osteoclasts are cells that break down and absorb bone tissue in the body, while osteoblasts create bone. They are large, multinucleated cells found in pits on bones and release enzymes to break down bone tissue into calcium and phosphorus ions. The resorption process is controlled by hormones, and osteoporosis occurs when the rate of bone loss exceeds regrowth due to hormonal changes. Only mineralized bone is affected by osteoclasts, and non-mineralized bone and cartilage formations are not resorbed.
Originally a term for a tool used to break bone during surgery, an osteoclast is now known as one of the two primary cell types the human body uses in the creation and maintenance of bone. Osteoblasts are the cells that actually create bone; osteoclasts are the cells that resorb, or break down and absorb, bone tissue in the body. They are highly specialized cells that must work in perfect synchronization with osteoblasts to maintain the skeletal system.
The osteoclasts themselves are very large cells, formed by the conjunction of several cells created by the bone marrow that travel in the circulatory system. As a result of this conjunction, osteoclasts are known as multinucleated cells, meaning that each cell has multiple nuclei. The average osteoclast has five to 20 nuclei, although some have up to 200 nuclei. These cells are usually found in small pits along the surface of the bone. These pits, which are formed by the action of osteoclastic enzymes, are known as Howship’s lacunae and can be found on virtually every bone in the skeletal system.
As the resorption process is initiated, the osteoclastic cell latches onto the bone to be resorbed, releases enzymes to deconstruct the tissue surface, then breaks it down into calcium and phosphorus ions, which the cell ultimately passes through the outer membrane and into the circle system. The resorption process, from first osteoclastic contact to the release of ions into the blood, can take up to three weeks to complete. The resorption process is controlled by hormones in the blood, which is why osteoporosis, a condition in which the rate of bone loss exceeds the regrowth of bone tissue, is closely linked to hormonal changes.
Osteoporosis is most commonly seen in postmenopausal women who have experienced a decrease in estrogen and in men who have experienced a decrease in testosterone production. In these men and women whose bodies have slowed down hormone production, the osteoclasts are reabsorbing more bone tissue than their osteoblasts are replacing. As a result, their bones can thin to the point where sudden fractures under minimal weight or force loads become possible or even probable. However, despite their role in bone resorption, osteoclasts do not break down all bone tissue. Only bone that has mineralized, or ossified to calcium and phosphorus, is affected by osteoclasts and their associated enzymes; non-mineralized bone and cartilage formations, such as the nose, are not resorbed.
Protect your devices with Threat Protection by NordVPN
