If we look at the animal kingdom, only 2% of us animals have internal bones. As a species, we are therefore part of a small minority to have the advantage of this internal, astounding thing called a skeleton.
The skeletal system provides structural support and keeps the body protected by means of 206 bones in the human adult. (Babies have more bones, approximately 300, many of which are cartilaginous, such as the kneecaps. These become ossified over time and fuse with other bones to become one bone). Not only bones, but the cartilage, ligaments and tendons connected to these bones gives the body its form, produces new blood cells, and assists the body to move by means of its muscles. Talking about this assistance to movement, it is therefore no surprise that the hands and feet contains over half the number of bones in our bodies. Each hand has twenty-seven bones; each foot twenty-six. Every bone is connected to another bone – remember that old song “Dem Bones”: “… knee bone connected to the thigh bone…”? – but for the hyoid bone, a horseshoe-shaped bone in the throat situated between the chin and the thyroid cartilage. (Had we not had that, human speech would not have been possible). The skeleton is also very important in maintaining the body’s calcium, phosphorus and acid-base status maintenance.
Weight for weight, bone is stronger than steel. It is strong and rigid and built to withstand a lot of force. In principle, a cubic inch of bone can bear a load of over 8000 kg – roughly the weight of five pickup trucks – but it depends strongly on how quickly or slowly that force is applied. (The slower, the better).
Bones are living things, made of active, living cells. As a single organ, the skeleton is formed and is broken down many times throughout our lives. The bone cells live inside what is called the bone matrix. The bone matrix consists of protein and mineral. The protein part, called the organic matrix, is made by the cells first, and mostly consists of collagen. The organic matrix is then mineralised by the deposition of hydroxylapatite. Our bones get broken down and absorbed by cells called osteoclasts, and build up and nourished by osteoblasts. In healthy bone the osteoclasts and osteoblasts live in perfect harmony. Unfortunately, as we age, (from about age 20 onwards!) the balance between bone formation and bone resorption can become unhinged, with the osteoclasts winning the competition. The result is called osteoporosis. (Females, especially postmenopausal, thin ones who smoke, drink too much and exercise too little are at greater risk to develop this than anybody else).
Aside from osteoporosis, bone fractures, cancer, and infections may be problems our bones can commonly run into.
How can we best take care of our bones?
- Exercise. Tai chi, yoga, brisk walking, golf, dancing, hiking and strength training all contribute to keep our bones as dense as they can be.
- Watch what we wear and watch where we walk. Going barefoot is best, but due to environmental factors not always feasible. Wear low heeled shoes, with rubber soles with good grip. When hiking or going downstairs look down and watch where we put our feet.
- Beware of some medication. Sleeping tablets, sedatives, antihypertensives, muscle relaxants, anticonvulsants and some antidepressants all can cause dizziness or some lack of coordination; making falls, and therefore fractures, more likely.
- Don’t smoke and use alcohol wisely.
- Make sure we get enough vitamin D and calcium.
