1. Nasal Cavity:
- Inhalation begins as we breathe in through our nose or mouth. The inhaled air first enters the nasal cavity.
2. Pharynx:
- From the nasal cavity, the air moves down the pharynx, which is the back of the throat.
3. Larynx:
- The air passes through the larynx, also known as the voice box.
4. Trachea:
- The trachea, or windpipe, is a tube that carries the air from the larynx to the lungs.
5. Bronchi:
- The trachea divides into two primary bronchi, one leading to each lung.
6. Bronchioles:
- Each primary bronchus branches into smaller tubes called bronchioles, which form an intricate network within the lungs.
7. Alveoli:
- The bronchioles end in tiny air sacs called alveoli. These alveoli are where the exchange of oxygen and carbon dioxide takes place.
8. Oxygen Exchange:
- Inside the alveoli, oxygen from the inhaled air diffuses across the thin alveolar walls and enters the bloodstream, while carbon dioxide moves from the bloodstream into the alveoli.
9. Pulmonary Capillaries:
- The oxygen-rich blood is carried away from the lungs by the pulmonary capillaries, which surround the alveoli.
10. Blood Circulation:
- The oxygenated blood is pumped by the heart to the rest of the body, delivering oxygen to tissues and organs.
This concludes the oxygen pathway when we breathe in. In essence, the respiratory system allows us to acquire the oxygen essential for cellular respiration and eliminate carbon dioxide, a waste product of metabolism, from the body.
