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Osteoporosis may also occur due to a number of diseases or treatments, including alcoholism, anorexia, hyperthyroidism, kidney disease, and after oophorectomy (surgical removal of the ovaries). Certain medications increase the rate of bone loss, including some antiseizure medications , chemotherapy , proton pump inhibitors , selective serotonin ...
Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts. Both processes utilize cytokine (TGF-β, IGF) signalling.In osteology, bone remodeling or bone metabolism is a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation).
Depending on where in the body bone resorption occurs, additional problems like tooth loss can arise. This can be caused by conditions such as hyperparathyroidism and hypovitaminosis D or even decreased hormonal production in the elderly. Some diseases with symptoms of decreased bone density are osteoporosis, and rickets.
Osteoporosis occurs when there is an imbalance between the bone resorption activities of osteoclasts and the bone formation activities of osteoblasts. [ 23 ] Osteoclast activity is also mediated by the interaction of two molecules produced by osteoblasts, namely osteoprotegerin and RANK ligand .
In normal bone, fractures occur when there is significant force applied or repetitive trauma over a long time. Fractures can also occur when a bone is weakened, such as with osteoporosis, or when there is a structural problem, such as when the bone remodels excessively (such as Paget's disease) or is the site of the growth of cancer. [79]
In developing bones, ossification commences within the primary ossification center located in the center of the diaphysis (bone shaft), [5] where the following changes occur: The perichondrium surrounding the cartilage model transforms into the periosteum. During this transformation, special cells within the perichondrium switch gears.
Secondary ossification mostly occurs after birth (except for distal femur and proximal tibia which occurs during 9th month of fetal development). The epiphyseal arteries and osteogenic cells invade the epiphysis , depositing osteoclasts and osteoblasts which erode the cartilage and build bone, respectively.
Rickets in children is similar to osteoporosis in the elderly, with brittle bones. Pre-natal care includes checking vitamin levels and ensuring that any deficiencies are supplemented. [23] Exclusively breast-fed infants may require rickets prevention by vitamin D supplementation or an increased exposure to sunlight. [24]