THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The alveoli are surrounded by tiny blood vessels, called capillaries. The alveoli and capillaries 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.

Detailed explanation-2: -The function of the respiratory system is to move two gases: oxygen and carbon dioxide. Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them.

Detailed explanation-3: -Each alveolus is cup-shaped with very thin walls. It’s surrounded by networks of blood vessels called capillaries that also have thin walls. The oxygen you breathe in diffuses through the alveoli and the capillaries into the blood.