Bone is a living tissue that supports our muscles, protects vital internal organs, and stores most of the body's calcium. Bone also contains living cells, including some that nourish the tissue and others that control the process known as bone remodeling. Throughout life, our bones are constantly being renewed by means of this remodeling process, in which old bone is removed (bone resorption) and replaced by new bone (bone formation). Bone remodeling is carried out through the coordinated actions of bone-removing cells called osteoclasts and bone-forming cells called osteoblasts. Osteoblasts are mono-nucleated cells that synthesize bone. These cells are fully involved in the anabolic activity in bones. Osteoclasts are multinucleated cells responsible …show more content…
As a result, bones grow in both size and strength. After you stop growing taller, bone formation continues at a faster pace than resorption until around the early twenties, when women and men reach their peak bone mass or maximum amount of bone. Peak bone mass is influenced by various genetic and external, or environmental, factors, including whether you are male or female (your sex), hormones, nutrition, and physical activity. Genetic factors may determine as much as 50 to 90 percent of bone mass; environmental factors account for the remaining 10 to 50 percent. This means you have some control over your peak bone mass. After your early twenties, your bone mass may remain stable or decrease very gradually for a period of years, depending on a variety of lifestyle factors such as diet and physical activity. Starting in midlife, both men and women experience an age-related decline in bone mass. Women lose bone rapidly in the first 4 to 8 years after menopause, which usually occurs between ages 45 and 55. By age 65, men and women tend to be losing bone tissue at the same rate, and this more gradual bone loss continues throughout …show more content…
Osteoporosis is the major underlying cause of fractures in postmenopausal women and the elderly. Fractures occur most often in bones of the hip, spine, and wrist, but any bone can be affected. Some fractures can be permanently disabling, especially when they occur in the hip. Osteoporosis is often called a “silent disease” because it usually progresses without any symptoms until a fracture occurs or one or more vertebrae collapse. Collapsed vertebrae may first be felt or seen when a person develops severe back pain, loss of height, or spine malformations such as a stooped or hunched posture. Bones affected by osteoporosis may become so fragile that fractures occur spontaneously or as the result of minor bumps, falls, or normal stresses and strains such as bending, lifting, or even coughing. Many people think that osteoporosis is a natural and unavoidable part of aging. However, medical experts now believe that osteoporosis is largely preventable. Furthermore, people who already have osteoporosis can take steps to prevent or slow further progress of the disease and reduce their risk of future fractures. Although osteoporosis was once viewed primarily as a disease of old age, it is now recognized as a disease that can stem from less than optimal bone growth during childhood and adolescence, as well as from bone loss later in life. There are two primary types of