Smoking may cause a person to become easily "winded" with even moderate exercise because several factors decrease respiratory efficiency in smokers, nicotine constricts terminal bronchioles, which decreases airflow into and out of the lungs. ... Irritants in smoke cause increased mucus secretion by the mucosa of the bronchial tree and swelling of the mucosal lining, both of which impede airflow into and out of the lungs. ... These changes cause collapse of small bronchioles and the trapping of air in alveoli at the end of exhalation , as a result gas exchange is less efficient. ... Atrial ...

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• Grade Level: High School

"Alveoli are "small cavities" or "air sacs in the lungs" ( Marieb G-2). ... The lungs are designed to receive air, which enters the body through the nose and mouth. The air passes through the pharynx and the larynx and enters the airways, beginning with the trachea and then into two primary bronchi. ... The tricuspid valve is made of three little triangular flaps of thin, strong fibrous tissue. ... Blood flows from the lungs back into the left side of the heart through four pulmonary veins and into the left atrium. ...

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The pain a patient receives after the surgery was put into a scale called the Lysholm scale. ... Helium-4 can change from a gas to a liquid to a super fluid, and when put in a container, forms a thin film on the surface. Oxygen can be produced from air that can be used in rocket engines, for cutting and welding torches, for supporting life in space and deep-sea vehicles, and for blast furnace operations. Nitrogen can also be produced from air for the making of ammonia for fertilizers, to prepare frozen foods, and to ship frozen foods. ...

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