Skeletal System Purpose and Functions

Skeletal System

Purpose and Functions

The skeletal system is fundamental to survival itself (Think Quest 1999). It keeps the body in shape. It protects vital organs, like the heart, the brain and the lungs, and enables the body to move. It consists of the spine, the ribs, the hands and feet, the hips and legs, the arms and the joints (ThinkQuest).

The spine serves as the central support of the body (ThinkQuest 1999). It consists of vertebrae and cartilages, which hold the bones together. The ribs form the thoracic case, which helps protect the chest. It is connected to the sternum, which makes them more flexible. Flexibility is necessary for breathing. The rib cage consists of 12 vertebrae, 24 ribs and a breastbone. It protects the heart and the lungs from falls, knocks and bumps (ThinkQuest).

The hands and feet are flexible because of their functions (ThinkQuest 1999). The bones in the toes are shorter and fatter than the bones in the fingers. These toe bones help balance the two feet. The hips and legs help keep the body in an upright position and in the movement it makes. The hips and legs support much of the body's weight. The arms are just as flexible because of their many functions. And the joints are used for bending, swiveling, stretching, pivoting and pointing (ThinkQuest).

Bones and How the Skeletal System Works

Bones provide the structure for standing erect and protect the soft or delicate inner parts of the body (Discovery Kids 2000). The skull consists of fused bones. It is on top of the body and acts like a protective helmet of the brain. The bones, or the vertebrae, in the spinal column surround it. The spine or spinal column consists of a complex group of nerves, which protect the heart and lungs in the rib cage. A newborn has more than 300 bones, but these fuse together as a person grows old so that an adult has only 206 (Discovery Kids).

Movements are made possible by bones and muscles (Discovery Kids 2000). Muscles and joints pull on the bones. Muscles are attached to bones, so that when muscles contract, the bones to which they are attached act as levers. They make body parts move. Joints, on the other hand, provide flexible connections between bones. There are joints in the knees, in the neck and the shoulders. Joints in the knees work like hinges of doors, moving the body back and forth. Joints in the neck enable the bones to pivot when the head turns. Shoulder joints enable the arms to move up to 360 degrees like the head of a shower (Discovery Kids).

Bones are made up of a hard substance, which makes them strong (Discovery Kids 2000). They also consist of living cells, which help them grow and repair themselves. Blood is also needed by the bone cells to keep them alive. Blood brings food and oxygen and removes waste matter from the cells. At the center of many bones is the bone marrow. This is what makes new red and white blood cells. Red blood cells are responsible for the transmission of oxygen to all the parts of the body. White blood cells are responsible for protecting the cells from germs and disease (Discovery Kids).

Maintenance number of minerals play an important role in nourishing the bone cells (Michael's 1996). They need sufficient amounts of calcium and phosphorus, the primary salt, which makes the bones hard. Vitamins, which play a role in the homeostasis of bone-building are Vitamins a, C and D. Vitamin a helps control the activity, distribution, and coordination of osteoblasts and osteoclasts during the stage of development. Vitamin C helps maintain the bone matrix and other connective tissues. Vitamin C is important for health bones, teeth and blood vessels. Vitamin a plays an important role in the immune system and the healthy formation of bones and teeth. Vitamin D is essential in normal mineralization of bone and cartilage (Michael's).

Calcium is also necessary for healthy and strong bones and teeth (Michael's 1996). Calcium is needed in blood clotting, stability and permeability of the membrane, nerve conduction, muscle contraction, cellular secretion, enzyme activity, and cell growth. Magnesium is needed for the metabolism of potassium and calcium and for the mobilization of calcium from bones. Phosphorus plays and important role in the development and maturation of the bone. Its chief role in bone resorption, mineralization and collagen synthesis makes it essential in calcium homeostasis (Michael's).

Diseases and disorders of the skeletal system include leukemia, bursitis, osteoporosis, sprains, fractures, spina bifida, scurvy, arthritis, scoliosis, talipes equinovarus or clubfoot, tendonitis, kyphosis and poliomyelitis (Family Shock 2001). Leukemia is also called cancer of the blood where abnormally large numbers of white blood cells multiply at an uncontrolled manner so that they interfere with the body's production of red blood cells. The cause is still unknown. Bursitis is a painful condition, which most commonly affects the hips and the shoulders. The bursa is inflamed. The bursa consists of small fluid-filled bags, which lubricate surfaces so that muscles can move over bones. The inflammation usually results from over-activity of an arm or leg. Osteoporosis is a disease caused by the loss of bone tissue. The cancellous bone is drained of calcium, becomes thinner or disappears altogether. A sprain is an injury to a ligament or tissue, which covers a joint. Most sprains occur from sudden stretches or tissue tears of the ligaments. Sprains are often very painful. The injured part usually swells and becomes "black and blue." A fracture is a broken bone. Spina bifida is a spinal defect, which occurs right at birth. In this condition, the spinal cord does not form properly around the vertebrae so that the skin cannot form around it. The cause is an error in the development of the embryo, which occurs about a month from the start of pregnancy. The use of alcohol or certain medications, exposure to extreme heat, or genetic factors may be responsible for the defect. Scurvy is a disease caused by the lack of Vitamin C or Ascorbic Acid in the diet. There is poor wound healing. Bruises come easily and the mouth and gums become sore. The gums also bleed, the teeth loosen, appetite becomes poor, the joints turn sore and there is restlessness. Arthritis covers more than 100 diseases of the joints. All types involve pain, stiffness and swelling of the joints. Osteoarthritis is a degenerative joint disease, where the joint wears out. It occurs frequently in the elderly, but it can also develop when a joint is repetitiously injured. The most affected joints are those in the hands, hips, knees, lower back and neck. Scoliosis is described as a side-to-side curve of the spine, which becomes visible during adolescence. The cause is still unknown, but it affects girls more than boys. Talipes equinovarus or clubfoot is an abnormal condition of the foot, usually discovered or present at birth. The foot is bent downward and inward, so that the child or person can walk only on his toes, heels or on the outside of his feet. Tendinitis or rheumatism is the stiffness or pain in the muscles or the joints. Kyphosis or hunchback is a forward bending of the spine, caused by anything, which deforms the bones in the upper part of the spine. Diseases, which cause kyphosis, include tuberculosis, syphilis, and rheumatoid arthritis. And poliomyelitis or polio is a serious disease, caused by the polio virus. This virus usually attacks the nerve cells of the brain and the spinal cord and causes paralysis. At first, the sufferer shows only slight symptoms, such as fever, headache, sore throat, and vomiting, which disappear after a day (Family Shock).