The skeletal system has five main functions. One function is movement; the skeletal system allows movement and the attachment of muscles, the muscles that are attached to the skeleton are called skeletal muscles. The muscles pull upon the bones during contraction, this results …show more content…
The matrix is made up of twenty-five per cent water, twenty-five per cent collagen fibres and fifty per cent crystallised mineral salts. There are four types of varieties of cells present; osteogenic cells, osteoblasts, osteocytes and osteoclasts. A bone is not entirely solid, it has small spaces between the cells and extracellular matrix. Some spaces act as channels for blood vessels that supply bone cells with nutrients. Other spaces act as storage areas for red bone marrow. The regions of a bone may be categorised as spongy and compact depending on the size and distribution of the spaces. In general, around eighty per cent of the skeleton is compact bone and twenty per cent is spongy bone (Tortoar and Derrickson, 2009). There are two types of bone tissues; compact and spongy. Compact bone tissue is hard and dense; it provides strength, support and protection. It forms the outer layer of all bones and most of the shaft of long bones such as the femur. Compact bone looks like honeycomb when examined microscopically and is found to consist of Haversian systems (Gould, 2005). In comparison, spongy bone has a spongy appearance to the naked eye. When examined under a microscope the Haversian canals are seen to be much larger than the compact bone. The spaces in spongy bone are filled with red bone marrow, which consists of fat and blood cells and in which red blood cells are made (Watson, 2011). Spongy bone is found at the end of long bones and in short, flat and irregularly shaped bones (Gould,