Healthy reSPIRatORy

Refresh What makes you breathe faster?

19 How do we breathe?

Our cells need oxygen to perform their vital functions. When we breathe, we get oxygen from the air and expel carbon dioxide. When we do an activity that is intense, our bodies need more oxygen.

1. Inhalation: the diaphragm contracts and the lungs expand. Air enters through the nose or the mouth.

2. Air travels to the lungs though the respiratory tract.

3. In the lungs, oxygen passes through the alveoli into the bloodstream.

4. At the same time, carbon dioxide travels from the blood, through the alveoli into the air in the lungs.

5. The diaphragm relaxes and the lungs contract.

6. Exhalation: air containing with carbon dioxide is expelled.

1 Order the steps of breathing in your notebook.

• Carbon dioxide leaves the blood and enters the lungs.

• Air containing carbon dioxide is expelled.

• Air travels to the lungs through the respiratory tract.

• The diaphragm contracts, the lungs expand and air enters.

• Oxygen passes through the alveoli into the bloodstream.

• The diaphragm relaxes and the lungs contract.

• Will you need extra oxygen if you are...

a) … reading?

c) … climbing a mountain?

b) … sleeping?

d) … running after a bus?

20

The respiratory system

The respiratory system is made up of the respiratory tract and the lungs. When air enters through our nose, it is filtered and warmed. Some microorganisms and harmful substances are prevented from entering the body. The respiratory system: a) The respiratory system is made up of the digestive tract and the lungs. b) Air is cooled when it enters our nose. c) Some harmful substances and microorganisms in the air enter our body. d) The exchange of gases takes place in the trachea. e) Oxygen leaves the body and carbon dioxide enters the blood stream.

• Regulates the temperature of inhaled air to match body temperature.

• Filters the air that enters our lungs.

• Delivers oxygen to the cells in our body.

• Eliminates carbon dioxide from our body.

2 Identify the true sentences and correct the false ones.