Human Organ Systems
The human body is made of organ systems that work together.
- The digestive system breaks down food; the respiratory system takes in oxygen; the circulatory system moves blood.
- The skeletal and muscular systems support and move the body; the nervous system controls it.
- Systems depend on one another — the lungs and heart work together to deliver oxygen.
No system works alone: each depends on the others to keep the whole body alive.