The skeletal system functions in helping to make blood cells.

When we think of the skeleton, we think of the bones that give the body its shape. But the skeletal system has other purposes, too. Without skeletal systems, vertebrates wouldn't be able to make new blood cells, or have healthy muscles and kidneys.

The average life span of a human red blood cell is about two months. Fortunately, our skeletal system helps to make new blood cells. Some vertebrate bones contain marrow in their centers. Marrow is a soft, fatty tissue that makes a special type of cell. These cells, when they divide, can then go on to become red blood cells to carry oxygen through the body, white blood cells to help fight infection, or platelets that help to make clots when an animal gets a cut.

When we think of the skeletal system, we usually think of calcium to build strong and healthy bones and teeth. Did you ever wonder why? Vertebrates need calcium to have their muscles and nerves work properly. Calcium also helps cells to communicate, stabilizes blood pressure, and aids in blood clotting. The vertebrate body keeps a consistent level of calcium circulating in the blood for these processes. When this level gets too low, it takes calcium from the skeletal system. Therefore, another purpose of the skeletal system is to store this important mineral.