Summary.—The skeleton, or framework of the body, is a structure which is movable as a whole and in most of its parts. It preserves the form of the body, protects important organs, and supplies the mechanical devices, or machines, upon which the muscles act in the production of motion. The skeleton is adapted to its purposes through the number and properties of the bones, and through the cartilage and connective tissue associated with the bones. The places where the different bones connect one with another are known as joints, and most of these admit of motion. The preservation of the natural form of the skeleton is necessary, both for its proper action and for the health of the body.
[pg 241]Exercises.—1. State the main purpose of the skeleton. What is the necessity for so many bones in its construction?
2. How may the per cent of animal and of mineral matter in a bone be determined?
3. What properties are given the bones by the animal matter? What by the mineral matter?
4. Locate the bone cells. What is their special function?
5. State the plan by which nourishment is supplied to the bone cells in different parts of the bone.
6. Give the uses of the periosteum.
7. State the purpose of the Haversian canals. Of the canaliculi.
8. Give functions of the spinal column.
9. Name the different materials used in the construction of a joint and the purpose served by each.