What is the pathway of oxygen gas molecules from an alveolus lung to right atrium heart and where are areas exchange?

The pathway of oxygen gas molecules from an alveolus lung to the right atrium heart through several areas of exchange, which include:

Alveoli: Oxygen gas molecules enter the alveoli during inhalation. The alveoli are tiny air sacs in the lungs where gas exchange takes place.

Pulmonary capillaries: The alveoli are surrounded by a network of tiny blood vessels called pulmonary capillaries. Oxygen gas molecules diffuse across the thin walls of the alveoli and into the pulmonary capillaries.

Pulmonary veins: The pulmonary veins carry oxygen-rich blood away from the lungs and back to the heart.

Right atrium: The pulmonary veins empty into the right atrium of the heart. The right atrium is the upper right chamber of the heart.

Therefore, the pathway of oxygen gas molecules from an alveolus lung to the right atrium heart involves the alveoli, pulmonary capillaries, pulmonary veins, and the right atrium, with the areas of exchange occurring in the alveoli and pulmonary capillaries.