The human body is organized into systems. A system is a group of tissues and organs that work together to do an important job for the body. Many jobs of the body involve cooperation between systems. The systems of the human body depend on each other. When one system is not working properly, it affects other systems as well. Click on the systems below to learn how each one works.

• Circulatory
• Digestive
• Respiratory
• Endocrine
• Skeletal

• Nervous
• Excretory
• Reproductive
• Muscular
• Integumentary