Question

In humans, what happens to oxygen after it is inhaled through the nose?

Answer 1

Fate of oxygen in the human body:

1. The inhaled air, which reaches the alveoli after passing through the trachea, bronchi and bronchioles is rich in oxygen and contains very little carbon dioxide.
2. The blood capillaries surrounding the alveoli, on the other hand, contain blood that has more carbon dioxide and less oxygen.
3. Thus, the oxygen diffuses through the thin walls of capillaries into the blood and combines with haemoglobin and forms oxyheamoglobin.
4. The blood enriched with oxygen is carried to all the cells of the body by the circulatory system, where it is utilised for the oxidation of glucose through the process of cellular respiration.
5. The overall reaction of cellular respiration is as follows:
   C₆H₁₂O₆ + 6O₂ ⇒ 6CO₂ + 6H₂O + ATP (Energy)
6. In the cells, during internal respiration, the carbon dioxide released as a by product combines with haemoglobin and forms carbaminohaemoglobin.
7. The blood rich in carbon dioxide leaves the cells and reaches the alveoli where carbon dioxide gas is released and then exhaled out through the nose.