The skeletal system is made up of bones and teeth. The normal human body has 206 bones which are needed for a variety of functions within the body. Bones are not static, which means they are constantly changing shape and composition to meet the body's needs. The role of bones extends beyond the function of giving your body its shape. There are many reasons why bones are important to the body.

One of the most important functions that bones have in our body is providing support and structure. Aside from teeth, bones are the hardest and most rigid structures in our body. According to the National Naval Medical Center, without bones the human body would essentially be nothing more than a shapeless blob of tissue. Bones are strong but light, which gives the body support and shape without weighing it down.

According to Minnesota State's Emuseum, the skeletal system also plays an important role in the protection of the vital organs throughout the body. This protective role is perhaps most obvious for the skull and the backbone (vertebrae) as these bones protect the central nervous system. This protective role is especially important because the central nervous system controls the rest of our body and is very fragile. The ribs also protect the vital organs in the chest, such as the lungs and heart.

The skeletal system also closely interacts with the muscle system in our bodies, to the point where sometimes the two systems are thought of as one entity—the musculoskeletal system. Although not all of our muscles need to be attached to bones in order to move (because we have muscles in our digestive and cardiovascular system that help these systems function), the muscles that we use for voluntary movement all require bones to work properly. Muscles are attached to bones by bands of tissue called tendons. Bones are necessary because the muscles need something to attach to in order to contract and cause motion.

According to the University of Michigan Comprehensive Cancer Center, the bones also are important as a center for the production of blood cells. The inside of bones is filled with a jelly-like material called bone marrow, which is where red blood cells (needed to transport oxygen throughout the body) are made. It is also where white blood cells (needed for the immune system), adipocytes (fat cells) and fibroblasts (needed to make connective tissue) are made.

Colorado State's Pathophysiology Department says that bones also are responsible for the regulation of calcium levels. Calcium levels in the blood have to be kept in a narrow range to make sure that nerves and muscles are able to properly work. Much of the body's calcium is stored in bones. When the body needs more calcium, bone tissue can be broken down to increase the blood's supply. Excess calcium can also be stored in bone tissue for later use.