THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -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-2: -When we breathe in, the millions of air sacs in the lungs fill with fresh oxygenated air. The oxygen then moves into the blood by passing first through the very thin walls of the air sacs and then into the capillaries, which are tiny blood vessels in a network within the lungs.

Detailed explanation-3: -Oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. This process is called diffusion. In the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells. This oxygen-rich blood then goes to the heart, which pumps it to the body.