Organ Systems The human body is made up of several organ systems that work together as one unit. Organ systems fit between the hierarchical levels of organs and the organism. Ten major organ systems of the body are listed below along with several organs that are associated with each system. It is important to keep in mind that these organ systems don't just exist as individual units. The final product of these cooperating systems is one unit call unit called the body 1. Circulatory System The main function of the circulatory system is to transport nutrients and gasses to cells and tissues throughout body. This is accomplished by the circulation of blood. Two components of this system are the cardiovascular and lymphatic systems. Cardiovascular: This system is comprised of the heart, blood, and blood vessels. The beating of the heart drives the cardiac cycle which pumps blood throughout body. Lymphatic: This system is a vascular network of tubules ...