Lesson 1 of 4 · Grade 6 Science and Technology
The breathing (respiratory) system
15 min
We breathe in oxygen and breathe out carbon dioxide.
Parts
- Nose: air enters here. Hairs and mucus trap dust and germs; air is warmed and moistened.
- Windpipe (trachea): carries air to the chest. It has rings of cartilage that keep it open.
- Bronchi: two tubes that lead into the lungs.
- Lungs: where oxygen enters the blood and carbon dioxide leaves it, in tiny air sacs called alveoli.
- Diaphragm: a muscle below the lungs that helps us breathe in and out.
Breathing in and out
- Breathing in: the diaphragm moves down, the chest gets bigger and air rushes in.
- Breathing out: the diaphragm moves up, the chest gets smaller and air is pushed out.
Diseases and care
Common cold, pneumonia, tuberculosis (TB) and asthma affect breathing. Avoid smoke and dust, keep rooms ventilated, cover your mouth when coughing, and get vaccinated.
Key points to remember
- We take in oxygen and give out carbon dioxide
- Gas exchange happens in the alveoli
- The diaphragm helps breathing
- TB and pneumonia affect the lungs
Test yourself
