Your Inner Framework: Understanding the Skeletal System

I think the skeletal system may be one of the systems we under appreciate. Obviously our body would just be a big blob laying on the ground if we didn’t have our skeletons, but these bones also do some major work for the body. Not only do they provide protection for our organs, but they store minerals and also have the incredibly important job of making the majority of our body’s blood cells in the bone marrow.

This system is made up of our bones and connective tissues (think your cartilage, ligaments and tendons- these are what hold your bones together). Your bone marrow is in the middle of your bones and does some heavy work for your body.

The Skeleton

The human skeleton is made up of about 206 bones and held together by connective tissues. One of the more obvious jobs of the skeleton is to protect the inside of our bodies. So many of our internal structures are incredibly delicate and rely on the hard structure of our bones for protection (think your skull around your brain). The skeleton also provides points for your muscles to attach to so that movement can occur. When two bones come together they create a joint allowing movement within that area. There is a hollow area inside many of your bones and this is where your bone marrow resides.

Movement

When two bones come together they form a joint. They are attached to each other by a ligament and often cushioned in between by cartilage to prevent the bones from rubbing together. Your bones provide a surface for muscles to attach to using tendons. This relationship is also very valuable for your skeleton as well. The pull on the bones from the muscles helps the bones to grow and become strong, when someone becomes bedridden we see a loss of bone strength and mass.

The Marrow

There is a hollow area inside many of your bones and this is where your bone marrow resides. It may surprise you that as an adult the majority of your red bone marrow is located within your pelvic bones, sternum, and the bones of your vertebral column. The cavity that holds your bone marrow contains a large blood supply. Your red marrow contains stem cells and this is where all of your blood components are made. Red Blood Cells (essential for oxygen and carbon dioxide movement) are released from here, as well as platelets (essential for blood clotting after an injury). White Blood Cells are essential to your immune system and they are formed here. This process is constantly occurring as blood cells have a limited life span. Red blood cells last the longest (about 120 days) while white blood cells work for only a few hours to a few days and platelets last for 5 to 9 days. Because of this it is estimated that DAILY your bone marrow produces 200 billion red blood cells, 10 billion white blood cells and 400 billion platelet cells. These cells are released into the capillaries within the bone marrow and carried into the larger vessels to enter the bloodstream.

Your bones contain both red and yellow marrow. Yellow bone marrow serves as storage for fat cells, it also contains stem cells that produce cartilage, fat and bone. Interestingly enough we are still scratching the surface on what this fat’s role inside of bone is. Originally it was thought to be a “filler” substance but more research is showing that it plays an active role in our body’s energy storage, bone and tumor creation and blood cell formation.

Minerals

The skeleton serves as a vital reserve for crucial minerals that the body needs. Two of these minerals are calcium and phosphorus. Calcium is so crucial to every system of your body, you would not be able to send signals along your nerves or move your muscles without it. Phosphorus is needed to release energy within the body, and is also critical for DNA. The body utilizes different hormones to let the bones know when minerals need to be released to be used elsewhere in the body. While it is great that the body can call on these reserves when we need them, it doesn’t come without a trade off. In order to stay strong and healthy bones are dependent on these minerals. When they are depleted to a certain point it leads to complications such as osteroporosis and bone fractures.