Details: This poster says at the top Major Human Body Systems . It shows labeled diagrams of four systems: Immune System, Organs of Excretion, Digestive System, and Endocrine System.
An immune system is a collection of mechanisms that protects against disease. Organs of excretion include the lungs, the kidneys, and the skin. The digestive tract is the system of organs that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. The endocrine system is an integrated system of small organs that involve the release of extracellular signaling molecules known as hormones.