ANATOMY

Detailed explanation-1: -At the end of each bronchiole are tiny air sacs called alveoli. This is the place where the exchange of oxygen and carbon dioxide actually happens. Each person has hundreds of millions of alveoli in their lungs.

Detailed explanation-2: -At the lungs, the blood picks up oxygen and drops off carbon dioxide. The blood then returns to the heart through the pulmonary veins.

Detailed explanation-3: -Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.

Detailed explanation-4: -Oxygen gets into the blood through tiny blood vessels around the alveoli. Red blood cells pick up the oxygen and deliver it to the body’s cells.

Detailed explanation-5: -The carbon dioxide produced is expelled through the lungs during exhalation. The benefit of the bicarbonate buffer system is that carbon dioxide is “soaked up” into the blood with little change to the pH of the system.