• Why do we need air? • We need air to breathe. The air we

breathe has oxygen. We cannot survive without oxygen.

• To help us achieve this, we have RESPIRATORY SYSTEM. It is the system of organs in the body which is responsible for taking in oxygen and giving out carbon dioxide.

What is respiratory system?

• The most important organ of the respiratory system are the lungs. They carry out the exchange of taking in oxygen and giving out carbon dioxide gases as we breathe.

• There are two lungs in our body.

• The other organs of the respiratory system are nose, mouth, trachea, rib cage, and diaphragm.

• When we inhale, or breathe in, the air goes into the windpipe through our nose.

• Fresh air with oxygen reaches the lungs from the windpipe.

• The oxygen mixes with the blood and reaches the heart.

• The heart pumps it and it reaches the other parts of the body.

• The blood then picks up carbon dioxide from other parts of the body.

• It reaches the lungs and the lungs exhale carbon dioxide.

The rib cage is another important organ. It goes around the lungs and the heart to protect them from damage. The ribs also move when we breathe in and out.

You can feel it working by doing the following exercise:• Put one hand on your chest and the other on

the upper part of your stomach. • Now, take a deep breath. You will feel your

chest and your stomach get bigger as the air goes into your lungs.

• The rib cage also moves as you inhale and exhale.

• In humans, the average rate of breathing is dependent upon the person’s age.

• A new born baby's normal breathing rate is about 40 times each minute and may slow to 20 to 40 times per minute when they sleep.

• For adults, the average breathing rate is 12 to 16 breaths per minute.

• Physical exertion also has an effect on respiratory rate. Healthy adults have an average of 45 breaths per minute while doing strenuous exercises.

Did you know?