Does Oxygen Diffuses from the Blood into the Alveoli?

As a result, oxygen diffuses across the respiratory membrane from the alveoli into the blood. In contrast, the partial pressure of carbon dioxide is high in the pulmonary capillaries and low in the alveoli. Therefore, carbon dioxide diffuses across the respiratory membrane from the blood into the alveoli.

How does oxygen diffuse from the alveoli to the blood?

Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body.

What diffuses out of the blood and into the alveoli?

Oxygen diffuses from the alveoli into the blood. Carbon dioxide diffuses from the blood into the alveoli. These three features are particularly important to our lungs for efficient gas exchange. Most of them also apply to other exchange surfaces such as the small intestine, body tissues and placenta.