the Body
Think of the body as divided into seven systems:
(click on the underlined links to learn more)
- [ bones ]
- [ brain and nerves ]
- [ muscles ]
- [ respiration ]
- [ circulation ]
- [ digestion ]
- [ glands ]
All are connected and interdependent, though each has a special network of its own.
The average woman has 206 bones in her body, but not always. She, like Adam, sometimes has an extra pair of ribs. A baby is born with about 350 bones, many of which fuse during the growing years. Bone growth and final size is mostly genetic, but can be influenced by environment and physical demands. Women usually reach their maximum height at sixteen, but that doesn't mean growth entirely ceases. The vertebral column increases from three to four millimetres between the ages of twenty and thirty. After fifty, stature often diminishes.
The function of bone is diverse. It gives shape and support, it protects certain organs and is an anchor for muscles. Although you may be able to relocate fat and influence muscles nothing can be done to alter the fundamental frame.
The word skeleton comes from a Greek word meaning 'dried bones'. Although one rarely gets an opportunity to see living bones, they are anything but dry. Bones have an outer layer of compact bone tissue that is pinky-white and crowded with tiny openings through which intertwine the network of nerves, arteries, veins and connective tissue. Inside, bones are a deep red with a mesh of spongy material containing that matter vital to life - marrow. Marrow is a combination of fat and tissue which manufactures all the red corpuscles. It also produces other constituents of blood and, most important, is a reservoir of minerals essential not only to the bone itself but to the general health of the body. Calcium and phosphorus are the two main minerals but there are also stores of magnesium, fluoride and chloride. These minerals are not stationary but constantly move on to fortify other areas and need to be replaced. Although rigid, bone is changeable and active.
The skeleton provides both firmness and also extreme flexibility. Some joints move like machinery, others remain locked. Think of what you can do with your thumb and what you can't do with your big toe.
The spinal column is the main bone structure and it supports the whole body. It is very flexible, on the average a little over 610 cm long and consists of thirty-three vertebrae. These are cylindrical bones with a central canal and strung together. There is a spongy circle of cartilage between each which makes the spine elastic and shock-absorbent. Running down either side are ligaments which help to hold it together.
Attached to the spine is the framework of the chest - twelve pairs of ribs and the breastbone. The ribs are of varying lengths but they all join the spine at the back, curving round to the front where the upper ribs join the breastbone. In this manner they form a protective cage for the heart and lungs, providing ample space for expansion during breathing.
The limbs are attached to the spinal column by special structures - the arms have the shoulder blades, the legs the pelvis. The pelvis is rather like a shell, holding in its strong frame the organs of the abdomen. Freedom of limbs comes from the ball-and-socket joints. The topmost bones of all comprise the skull, where size and placement determine facial features.
[ the Body ]
Think of the body as divided into seven systems:
(click on the underlined links to learn more)
- [ bones ]
- [ brain and nerves ]
- [ muscles ]
- [ respiration ]
- [ circulation ]
- [ digestion ]
- [ glands ]
All are connected and interdependent, though each has a special network of its own.
Return to [ the Body ] Index page!