Haemoglobin, a respiratory pigment in red blood cells, has a high affinity for oxygen, facilitating its transport from the lungs to oxygen-deficient tissues.

Diffusion pressure alone becomes insufficient for oxygen delivery to all body parts in large animals.

The walls of alveoli contain an extensive network of blood vessels. These vessels facilitate the exchange of gases, allowing oxygen from the alveolar air to be absorbed by the blood and transporting carbon dioxide from the blood into the alveoli.

During the breathing cycle, when air is taken in and out, the lungs always retain a residual volume of air. This ensures sufficient time for the absorption of oxygen and release of carbon dioxide, facilitating effective gas exchange for cellular ...

Alveoli are balloon-like structures within the lungs where the exchange of gases occurs. They provide a surface for the absorption of oxygen and release of carbon dioxide.