During internal respiration, oxygen (O2) and carbon dioxide (CO2) diffuse in opposite directions.
Oxygen diffuses from the blood into the body’s tissues. This happens because the oxygen concentration is higher in the blood compared to the tissues. The oxygen is carried by red blood cells and is released into the tissues where it is needed for cellular respiration.
On the other hand, carbon dioxide diffuses from the tissues into the blood. This occurs because the carbon dioxide concentration is higher in the tissues due to the production of CO2 as a waste product of cellular respiration. The blood then carries the CO2 back to the lungs where it is exhaled.
In summary, during internal respiration:
- O2 diffuses from the blood to the tissues.
- CO2 diffuses from the tissues to the blood.