ANATOMY

Detailed explanation-1: -The capillaries are thin walled because they help in the exchange of gases and diffusion of materials into the cells. This diffusion is possible due to the thinness of its walls.

Detailed explanation-2: -The walls of capillaries are extremely thin. This property allows nutrients and oxygen to travel through the bloodstream and diffuse into the tissues. As a result, waste materials can diffuse out of tissues into the bloodstream and be carried to the lungs, where they can be re-oxygenated.

Detailed explanation-3: -a) The alveoli wall (and the capillary wall) is only one cell thick so there is only a short distance over which diffusion takes place (short diffusion pathway) so there is a faster rate of diffusion of oxygen from alveoli into the blood.

Detailed explanation-4: -Capillaries are where fluids, gasses, nutrients, and wastes are exchanged between the blood and body tissues by diffusion. Capillary walls contain small pores that allow certain substances to pass into and out of the blood vessel.

Detailed explanation-5: -Capillaries connect the smallest branches of arteries and veins. The capillaries are where molecules are exchanged between the blood and the body’s cells. The walls of capillaries are just one cell thick. Capillaries therefore allow molecules to diffuse across the capillary walls.