The walls of capillaries are made of one cell cell layer so it is a small diffusion barier. They have the greatest total cross-sectional area and the slowest velocity of blood flow. This enhances exchange.
The wall of a capillary is extremely thin.
The capillary cell wall receives blood from the interstitial fluid.
Capillary walls receive oxygen in the lungs by a process known as diffusion.
Epithelial Tissues?
Capillaries do not vary in thickness, they are very thin. The thin wall permits the exchange between the blood in the capillary and the adjacent tissue cells.
A capillary has a very narrow lumn and very thin wall. These features maximize diffusion of nutrients, wastes, and oxygen.
Slow flow speed in the capillary increases the efficiency of diffusion. In addition, the thin wall of the capillary helps substances to pass through efficiently.
Capillary
Capillaries have very thin walls which are semi-permeable.
Diffusion
go look in your book punk
Villi