Body Systems Working Together
- Biology
- Ages 11–14 · Grades 6–8
What you’ll find out
- Many-celled organisms are organised as cells, tissues, organs, organ systems and the whole organism.
- Each organ contains several tissues, and each organ system contains several organs.
- Body systems depend on one another, as exercise shows for the nervous, respiratory, circulatory and digestive systems.
No sign-up and no real names. In the lesson you check your understanding as you read, and practise until it sticks.
From cells to systems
Many-celled living things are organised in levels. The simplest level is the cell. A group of similar cells working together forms a tissue, such as muscle tissue or nerve tissue. Different tissues combine to form an organ, like the heart, lungs or stomach. Several organs working together make up an organ system, such as the digestive system. Finally, all the organ systems together make a complete organism. Even your skin counts as an organ, and it is the largest one. Each level is built from the one below it.
Systems depend on each other
Body systems do not work alone; they depend on one another. Imagine running for a bus. Your muscles need more energy, so your nervous system makes you breathe faster and deeper, and your respiratory system takes in extra oxygen. Your heart speeds up, and your circulatory system rushes that oxygen, along with sugar absorbed by your digestive system, to your muscles. Meanwhile, waste carbon dioxide is carried back to your lungs and breathed out. When you stop, your breathing and heart rate slowly return to normal.
Curriculum links: NGSS MS-LS1-3 · England KS3: Structure and function of living organisms · Cambridge Lower Secondary Stages 7–9: Biology · NCERT Science, Classes 6–8