When pondering your overall health, do you consider the stick-like structure that prevents you from collapsing to a blob of flesh on the floor? I must confess that I don't. But a sickly skeleton is no laughing matter, and in this cancer-filled century you should know a few facts.
What are Bones?
The human body is made up of over 200 bones of different shapes and sizes,
and categorized into “long bones” and “flat bones.” While we tend to think of
bones as dry and brittle, they actually have living cells called osteocytes
that are bound together by a hard, calcium-like material that makes bones
strong and rigid. These living cells are constantly rebuilding the bone. Osteoclasts
are the cells that dissolve the bone, and osteoblasts form the new bone.
Periosteum is the name of the layer of fibrous tissue that covers the
outside of bones. Their insides are hollow and filled with a spongy material
called bone marrow. Bone marrow produces the body’s blood cells.
In addition to making blood, bones support body structure, store essential
minerals like calcium, and work together with muscles to facilitate movement.
Flat bones protect organs in the body; for example, the ribcage protects the
heart and lungs, and the skull gives protection to the brain. As a group, the
bones of the body are known as the skeleton.
The majority of bones are long bones, tubular in structure with yellow
marrow filling the middle. The round portions found at the end of long bones
are called epiphysis, and are composed of red marrow and a spongy
material known as cancellous. Muscles that move the arms and legs are
attached to these bones.
A tough, flexible material called cartilage covers the joints of the
bones. Its flexibility allows free movement at the joints and provides a
cushion to prevent the bones from rubbing against each other.