[HuiLi]

Why does carbon dioxide and oxygen diffuse in opposite directions? Can anyone explain to me in simple form

[Unknown008]

Which are the directions you are referring to? :confused:

In the air, gases diffuse in all directions. Are you talking in a specific area in the body, in a plant?

[HuiLi]

It is an area in the body I'm not sure because the question just show a picture wuth headings

[Unknown008]

Well, if so, it can either be in the lungs or near cells.

In the lungs, you have a greater concentration of oxygen and a lower concentration of carbon dioxide from the air. From the blood (in the pulmonary artery), you have more carbon dioxide and less oxygen. This is because your cells have used the oxygen for making energy and released carbon dioxide as a by-product. Diffusion of oxygen occurs from the lungs to the blood and carbon dioxide from the blood to the lungs.

Near cells, as I told you, the cells take in oxygen and release carbon dioxide. Hence, there is a lower concentration of oxygen in the cells, and a higher concentration of carbon dioxide in the cells that in the blood (from any artery except pulmonary artery) carrying oxygen and a little carbon dioxide. Therefore, diffusion occurs where oxygen from the blood go into cells and carbon dioxide from the cells to the blood.

I hope it helped! :)

[tool8er]

Yes agreed. Think diffusion and why diffusion happens. Alveolar versus venous capillary (external respiration) and arterial capillary versus tissue (internal respiration). Nomenclature and convention = PAO2 (calculated)/PACO2, (PAO2 = {(Pb - PH2O) x FIO2} - (PaCO2 x 1.25)) versus PaO2/PaCO2 and PvO2mixed.