The skeleton consists of 206 bones, according to the Minnesota State University (MNSU) Biology Department. When put together, the skeletal system provides the base framework to which all the other tissues and organs attach, forming the human body. According to ThinkQuest, the human skeleton has two distinct features, including opposable thumbs and an erect structure which enables walking on two legs. The skeletal system is divided into two parts, axial skeleton (including all of your body's bones) and the appendicular skeleton (referring to the arms and legs), and has five main functions.
Shape
The structure of the bones give the underlying shape to the body. Shape develops over the growth of an individual and the skeletal system will determine if they are tall or short, wide or narrow and other factors, such as the size of hands and feet. According to the Student Nutrition (& Body Image) Action Committee from UCLA, body shape or type is genetically inherited. Three types of body shapes include ectomorphs (tall and thin), mesomorphs (shorter and muscular) and endormorphs (apple or pear-shaped).
Support
The skeleton provides support to the body and holds internal organs in their place. The vertebral column allows for standing erect while cavities, or hollow spaces, of the skeleton are designed to hold organs within them. For example, the skull holds the brain, the chest cavity holds the lungs and the heart while the abdominal cavity holds gastrointestinal organs. Additionally, according to ThinkQuest, the lower appendages, or feet, are strong and thick to support the weight of the entire skeleton, while the foot possesses an arch to enable this kind of support.
Movement
The skeletal bones attach to each other by ligaments and further attach to muscles by tendons. According to MNSU, the muscular and skeletal system work together to carry out bodily movement,and thus are jointly called the musculoskeletal system. When muscles contract, bones are pulled along to produce a movement allowing people to walk or run. The shape of the skeletal system also has a role in movement. According to ThinkQuest, the many small bones of the foot allow for adaptation to all sorts of terrain, while the small bones in the hands allow for precise and detailed movement.
Protection
The skeleton protects vital organs from damage by encasing them within hard bones. The cranium encases the brain, while the vertebral, or spinal, column protects the delicate spinal nerves, which control all bodily functions by allowing all body parts to communicate with the brain. The bony thorax, comprised of the ribs and sternum, provides protection to the heart and lungs.
Blood Cell Production and Storage
The spongy tissue inside long bones, such as the femur, or thigh bone, have two types of marrow responsible for blood cell production. MNSU states that, on average, 2.6 million red blood cells are produced each second by the bone marrow. According to ThinkQuest, red bone marrow gives rise to blood cells while yellow bone marrow stores fat, which turns into red bone marrow in case of severe red blood cell depletion or anemia.
According to Dr. Odgren from the University of Massachussets Medical School, skeletal bones also function as a storage "bank" for minerals, such as calcium and phosphorus. These minerals are necessary for vital body functions, such as nerve transmission and metabolism.
