From our head to our toes, bones provide support for our bodies and help form our shape. The
skull protects the brain and forms the shape of our face. The spinal cord, a pathway for
messages between the brain and the body, is protected by the backbone, or spinal column.The
ribs form a cage that shelters the heart, lungs, liver, and spleen, and the pelvis helps protect
the bladder, intestines, and in women, the reproductive organs.
Although they're very light, bones are strong enough to support our entire weight.The human
skeleton has 206 bones, which begin to develop before birth. When the skeleton first forms, it
is made of flexible cartilage, but within a few weeks it begins the process of ossification.
Ossification is when the cartilage is replaced by hard deposits of calcium phosphate and
stretchy collagen, the two main components of bone. It takes about 20 years for this process
to be completed.
The bones of kids and young teens are smaller than those of adults and contain "growing
zones" called growth plates. These plates consist of columns of multiplying cartilage cells that
grow in length, and then change into hard, mineralized bone. These growth plates are easy to
spot on an X-ray. Because girls mature at an earlier age than boys, their growth plates change
into hard bone at an earlier age.
Bone healthy actions should begin in childhood and continue throughout your lifetime.
However, it's never too late to take action to promote healthy bones.
Bone healthy actions are the keys to enable you to build and maintain strong bones. These include:
• eating a well-balanced diet rich in calcium and vitamin D;
• participating in regular exercise;
• taking safety precautions to protect your bones and prevent falls;
• limiting alcohol intake;
• maintaining normal hormonal balance in premenopausal women;
• avoiding excessive dieting and excessive thinness; and
• talking to a medical professional about promoting healthy bones