As food passes through the digestive system, it gets disassembled, distributing its nutrient value to the body along the way. The human body also produces wastes that aren't useful. These waste products needs a system to eliminate them.
8.2 - Circulatory, Respiratory, and Lymphatic Systems
Working together, your circulatory and respiratory systems supply cells throughout the body with the nutrients and oxygen that they need to stay alive.
8.3- Endocrine System
Endocrine - Glands that release hormones into the blood stream to broadcast messages throughout the body. This system is called often called the "slow messaging" system.
8.4 - Nervous System
Control and coordination of functions throughout the body as well as response to internal and external stimuli. This system is often called the "fast signaling" system.