Orthopedic surgeons receive 5 or more extra years of training after school. 1  They specialize in the care of disorders of the bones, muscles, tendons, and ligaments. They are trained to manage joint problems with both operative and non-operative techniques.
What the Immune System Does. The immune (pronounced: ih-MYOON) system, which is made up of special cells, proteins, tissues, and organs, defends people against germs and microorganisms every day. In most cases, the immune system does a great job of keeping people healthy and preventing infections.
The human body is made up of several organ systems that all work together as a unit to make sure the body keeps functioning. There are ten major organ systems in the body, each of which plays a different role in helping the body work. This system is made up of the heart, blood, blood vessels, and lymphatics.