APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -Capillaries have thin walls that allow oxygen, nutrients, carbon dioxide and waste products to pass through, to and from the tissue cells. Veins then carry the blood back to your heart, and the process begins again.

Detailed explanation-2: -CAPILLARIES are blood vessels in the walls of the alveoli. Blood passes through the capillaries, entering through your PULMONARY ARTERY and leaving via your PULMONARY VEIN. While in the capillaries, blood gives off carbon dioxide through the capillary wall into the alveoli and takes up oxygen from air in the alveoli.

Detailed explanation-3: -Cellular Level Once the venous blood returns to the lungs, the carbon dioxide diffuses out of the bloodstream, through the capillaries, and into the alveoli from where it is expelled, during which time oxygen simultaneously binds with hemoglobin to be carried back to the tissues.