Discusses bone composition, factors that influence bone health, guidance on supplementation with Calcium and Vitamin D, the importance of exercise, and concerns about medication, osteoporosis and fractures.
There are 206 seperate bones in the human body. Collectively they form the skeletal system.
Some bones have a protective function, like the skull. Others are mainly supporting structures, like the pelvis. Other bones, such as the jaw and finger bones, are chiefly concerned with movement
The bones themselves act as a storehouse of calcium, which must be maintained at a certain level in the blood for the body’ s normal chemical functioning.
Bone is mostly made up of collagen, a protein, which provides a soft framework. Calcium phosphate a mineral, which adds strength and hardens the framework. This combination of collagen and calcium makes bones strong and flexible to withstand stress. More than 99% of the body’s calcium is found in the bones and teeth. The remaining 1% is found in the blood.
There are two kinds of bone found in our bodies:
1. Cortical (kȯr-ti-kəl) bone is dense and compact. It forms the outer layer of the bones. Your legs and arms are examples of cortical bone.
2. Trabecular (trə-ˈbe-kyə-lər) bone makes up the interior of bone. It has a spongy, honey comb like structure. Your spine, hips and heel are good examples of trabecular bone Cortical Bone trabecular bone.
Throughout life, bone is constantly renewed through a process called “remodeling”. This process consists of 2 stages:
Resorption: During resorption, old bone tissue is broken down and removed by special cells called osteoclasts. Once this has been done, formation takes place.
Formation: Bone formation begins and new bone tissue is laid down to replace the old. This task is performed by special cells called osteoblasts.
Think of bone as a bank account, where you "deposit" and "withdraw" bone tissue.
During childhood and the teenage years, new bone is added to the skeleton faster than old bone is removed. As a result, bones become larger, heavier, and denser. These are the years we need to be concerned about building strong bones. Bone formation continues at a faster pace than removal until peak bone mass is reached between ages 25-35.
At 35 years of age, we begin to tear down more bone (resorption) than we rebuild (formation). This process will go on for the rest of our lives, so it is very important to build strong bones in your early years.
Osteoporosis results from not having enough bone tissue, (low bone density). Low bone density and structural weakness lead to bones that can break under the slightest strain. Many persons with osteoporosis will become bent over (dowager hump), caused by compound fractures of the vertebrae in the spine. Osteoporosis can be a very painful and life threatening disease. A bone mineral density test (BMD) can measure bone density in various sites of the body.
