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.
Image: Nervous system. The nervous system is made up of two parts: 1  The central nervous system (CNS) is made of the brain and spinal cord. 2  It receives information and responds to it. 3  The peripheral nervous system (PNS) is composed of the nerves extending from the brain and spinal cord to the rest of the body.mage: The bodyâs systems. Cardiovascular system. The heart and blood vessels make up this system. The heart is a pump forcing blood into a network of blood vessels allowing it to travel to organs and delivery sites requiring oxygen gas for respiration, nutrients and the removal of waste substances.