the direction of movement of oxygen from the air you breathe and to dispose of excess.
diffusion
From the blood to the cell.
oxygen out of blood, carbon dioxide into blood
Oxygen enter the capillaries by diffusion due to difference in oxygen concentrations.
It diffuses because the concentration of oxygen in the capillaries is lower than the concentration of oxygen in the air (law of diffusion).
Capillaries exchange food, oxygen, and carbon dioxide.
Oxygen passes into the capillaries that surround the alveoli. The thin walls of the capillaries make this diffusion easier.
greater concentration of oxygen in the air sacs of the lungs than in the capillaries.
Capillaries must allow diffusion too allow for exchange of oxygen. Without oxygen, the eventual consequence would be death.
capillaries
capillaries
Oxygen