Blood passes through the capillaries, which provide a passage way for the blood from the arteries to the veins. The tiny, thin walled capillaries also allow for the exchange of gases through the tissue. You can read more about capillaries at fi.edu
Gases pass through
Oxygen passes into the capillaries that surround the alveoli. The thin walls of the capillaries make this diffusion easier.
The alveoli and capillaries in the lungs pass oxygen to the blood. Both have very thin walls, which allow the oxygen to pass from the alveoli to the blood. The capillaries then connect to larger blood vessels, called veins, which bring the oxygenated blood from the lungs to the heart.
The walls of capillaries are very thin allowing the nutrients of cells to diffuse through them. They facilitate the diffusion of nutrients to the body by passing them through their cell walls.
Capillaries
Capillaries
The walls of alveoli are thin to allow the exchange of gases (Co2 and O2) between blood capillaries and the aveoli in the lungs.
Capillaries
The air sac must have thin walls so that air passes easily through it.
Capillaries have thin walls to optimise the level of diffusion of oxygen and other nutrients in the blood stream to the surrounding cells.
gas exchange occurs between the thin walls of the alveoli and the thin walls of the capillaries
Capillaries are very thin blood vessels. Oxygen and nutrients and hormones can pass through the walls of the capillaries and reach the body's cells, while red blood cells remain in the capillaries.
it is because for the diffusion of water and oxygen molecules