There are many important systems in the body that help dictate how it works. The skeleton might be the most important system in the body. The skeleton provides so many useful functions to the body that it can be easy to take it for granted. It is easy to forget the ways that the skeleton helps us run, jump, breathe and live. Without the skeleton, life would be impossible. Understanding the functions that the skeleton serves can reintroduce the importance of the skeleton to anybody who has forgotten.
The skeleton holds the body together. Attached to each bone are ligaments, muscle, sinew, organs, veins, and other body tissue. Without the skeleton, a body would be a messy pile of goo. The hard bones in the skeleton give shape to the body forming a rigid frame that holds everything together and keeps everything where it is supposed. This is perhaps the most important function of the skeleton.
Without the skeleton, the body could not move. Using a complex interaction between muscles and bones, movement is carried out. Each muscle is connected to at least two bones in the body by ligaments. When the muscle contracts, it pulls the bones closer together. The structure that the bone gives to the muscles and body dictates the movements that a body can make. If the biceps flex, the muscle pulls the lower arm up toward the top. When the muscles in the legs bend the knee, it brings the lower leg up and back toward the top. The knee is an example of a joint, which is a flexible connection between two bones. Joints dictate the direction the bones can meet.
Red blood cells are worn out and destroyed by the liver on a daily basis. The bones in the skeleton help replace these cells. In certain bones, there is a substance called bone marrow. This is where all red blood cells are created. Red blood cells are vital to the body as they transport life-giving oxygen from the lungs to the rest of the body. Blood marrow produces about 2.6 million blood cells per second. Without marrow, our bodies would shut down from lack of oxygen very quickly.
Bones also help store minerals. This is one of their most useful and least known functions. The body receives minerals, such as calcium or phosphorus every day from the food we eat and the liquids we drink. Sometimes, too many of these minerals will become present in the blood. The bones of the skeleton will absorb these excess nutrients if necessary. Perhaps most importantly, bones will actually supply these minerals to the blood stream when they are low. This balancing system helps keep the body healthy and supplied with the minerals it needs.
The skeleton also offers protection against physical harm. The bones are the hardest structure inside of the body. Muscles, organs and other tissues are not built to withstand great physical force. The skeleton is built in such a way that it will absorb the most physical damage when the body is injured. Though this will lead to broken bones, it is better than the kidney or the liver being damaged. The rib cage is a perfect example of protective bones. They build an arc of bone protection around the most vital organs in your body, which include the heart and lungs. Some creatures, such insects, turtles, crocodiles, and shell fish, have what is referred to as an exoskeleton. An exoskeleton exists on the outside of the creatures skin, instead of the inside. The most striking visual image of a creature using it's exoskeleton for protection is a turtle withdrawing into it's shell.