What is the path af oxygen from outside body to alveoli?

Oxygen's path from outside the body to the alveoli involves several stages:

1. Nasal Cavity or Mouth: Oxygen enters the body through the nasal cavity or the mouth during inhalation.

2. Pharynx: From the nasal cavity or mouth, the inhaled air passes into the pharynx, which is the back of the throat.

3. Larynx: The air then travels down the larynx or voice box, which connects the pharynx to the trachea.

4. Trachea: The trachea is the windpipe that carries the air from the larynx to the lungs.

5. Bronchi: Inside the lungs, the trachea branches into two primary bronchi, one leading to each lung.

6. Bronchioles: The bronchi further divide into smaller branches called bronchioles, forming an intricate network within the lungs.

7. Alveoli: The bronchioles end in tiny sacs called alveoli. Alveoli are where the actual exchange of gases occurs between the air and the bloodstream.

The alveoli have a dense network of capillaries, which are the smallest blood vessels. Oxygen molecules diffuse across the thin walls of the alveoli and capillaries, entering the bloodstream and eventually reaching all cells and tissues in the body. Simultaneously, carbon dioxide, a waste product of cellular respiration, diffuses from the bloodstream into the alveoli to be exhaled.

This continuous process of gas exchange, facilitated by the respiratory system, ensures that oxygen is delivered to the body's cells, and carbon dioxide is removed, maintaining essential life processes.