Respiratory system in humans

• Humans, like other land animals with backbones, breathe in oxygen-rich air and breathe out carbon dioxide-rich air with the help of lungs. Lungs are present inside our chest (also called the thorax).

Human respiratory system

• They are protected by the rib cage that forms a sort offence around them. The ribs also support the respiratory system in human beings.
• The ribs also support the lungs and help to pump air in and out when we breathe.
• Just beneath the lungs is a dome-shaped muscle called the diaphragm.
• When the diaphragm contracts, oxygen-rich air is pulled into the lungs.
• When the diaphragm relaxes, carbon dioxide-rich air is pumped out of the lungs.

Breathing and Respiration:

• As we inhale, the air follows the route.

• Air is exchanged in the alveoli.
• Oxygen absorbed in the alveoli is picked up by the blood.
• On the other hand, carbon dioxide is picked up from all the body parts and is transported by the blood to the lungs.

Process of breathing

• When we exhale, the carbon dioxide-rich air follows the reverse route, finally moving out through the nose. This is the process of breathing.

Process of breathing

• The oxygen absorbed in the alveoli while breathing combines with haemoglobin in the blood.
• This is carried as oxyhaemoglobin to all parts or cells of the body. In these cells, oxygen helps to break down food (glucose or sugar) to release energy.
• The chemical reaction involved in this breakdown of sugar is:

Sugar + Oxygen → Energy + Carbon dioxide + Water

• This is the process of respiration. Along with energy, carbon dioxide, and water, is also released during respiration.