In a short paragraph, describe the process of gas exchange in the lungs, including the section of the circulatory system that pertains to respiration. Begin the description with fresh air entering from the nose and mouth. The following terms should be included in the explanation:
trachae,alveoli, bronchi, capillaries, veins, arteries, atrium, ventricle, oxygen, carbon dioxide.
Fresh, oxygenated air enters through the mouth and nose, passes through the trachea (throat) and bronchi into the lungs. In the lungs, the air passages end in tiny sacs called alveoli that are enclosed with thin membranes where the actual gas diffusion takes place. Tiny blood vessels called capillaries are embedded in the membrane. The blood flowing through these capillaries releases carbon dioxide into the lungs and absorbs oxygen from the freshly inhaled air. The oxygenated blood passes through the heart and is distributed to the body through the arteries. The "spent" blood that has picked up carbon dioxide and waste products is then carried through the veins back to the lungs to repeat the gas diffusion process all over again. Blood enters the heart through the atria and exits the heart through the ventricles.