MICROANATOMY

Detailed explanation-1: -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-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: -Red blood cells pick up oxygen in the lungs. Blood travels away from the heart and lungs through the arteries (ar-tuh-reez). Red blood cells drop off oxygen to the cells through tiny tubes called capillaries (cap-ill-air-ies). Blood then returns to the heart through the veins (vayns) and the cycle begins again.

Detailed explanation-4: -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.

Detailed explanation-5: -Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body.