1. Topic 6: Body Systems in Humans
All cells in the human body require a constant supply of food and oxygen in order for the body to produce energy. Three organ systems work together to ensure this happens:
Digestive System
Food enters the body through the mouth, then passes into the stomach, and then into the intestine.
The stomach and intestine break down food particles into small particles that can be used by cells.
Unused particles become waste and is released by the water.

2. 2. Respiratory System
Inhalation fills our lungs with air, (which contains oxygen).
Exhalation rids our lungs of waste air, (carbon dioxide etc.)
This system allows for gas exchange.
3. Circulatory System
Transports particles of food and oxygen.
Consists of the heart, blood, and blood vessels.
Circulates blood around the body, delivering food particles, dissolved gases, and other materials to all the cells in the body.
Carries away cell wastes.

3. 3. Circulatory System
Transports particles of food and oxygen.
Consists of the heart, blood, and blood vessels.
Circulates blood around the body, delivering food particles, dissolved gases, and other materials to all the cells in the body.
Carries away cell wastes.