Skeletal System

Even though bones are very strong, they may be broken, but fortunately, most fractures do heal. The healing process may be stymied if bones are not reset properly or if the injured person is the victim of malnutrition. Osteoprogenitor cells migrate to the site of the fracture and begin the process of making new bone (osteoblasts) and reabsorbing the injured bone (osteoclasts). With proper care, the fracture will fully heal, and in children, often without a trace.

Bones are affected by poor diet and are also subject to a number of diseases and disorders. Some examples include scurvy, rickets, osteoporosis, arthritis and bone tumors. Scurvy results from the lack of vitamin C. In infants, scurvy causes poor bone development. It also causes membranes surrounding the bone to bleed, forming clots which are eventually ossified, and thin bones which break easy. In addition, adults are affected by bleeding gums and loss of teeth. Before modern times, sailors were often the victims of scurvy, as they were at sea for long periods of time with limited food. Hence, they tried to keep a good supply of citrus fruits, such as oranges and limes, on board, as these fruits supply vitamin C.

Rickets is a children's disease resulting from a deficiency of vitamin D. This vitamin enables the body to absorb calcium and phosphorus, and without it, bones become soft and weak and actually bend, or bow out, under the body's weight. Vitamin D is found in milk, eggs and liver, and may also be produced by exposing the skin to sunlight. Pregnant women can also suffer from a vitamin D deficiency, osteomalacia, resulting in soft bones. The elderly, especially women who had several children in a row, sometimes suffer from osteoporosis, a condition in which a significant amount of calcium from bones is dissolved into the blood to maintain the body's calcium balance. Weak, brittle bones dotted with pits and pores are the result.

Another condition commonly afflicting the elderly is arthritis, an often painful inflammation of the joints. Arthritis is not, however, restricted to the elderly, as even young people may suffer from this condition. There are several types of arthritis, such as rheumatoid, rheumatic and degenerative. Arthritis basically involves the inflammation and deterioration of cartilage and bone at the joint surface. In some cases, bony protuberances around the rim of the joint may develop. Unfortunately, most people will probably develop arthritis if they live long enough. Degenerative arthritis is the type that commonly occurs with age. The knee, hip, shoulder and elbow are the major targets of degenerative arthritis. A number of different types of tumors, some harmless and others more serious, may also affect bones.