Text. A. The Lungs.

Medical terms related to the lung often begin with pulmo-, from the Latin pulmonarius ("of the lungs"), or with pneumo- (from Greek πνεύμων "lung").

The lungs are the main organs in the respiratory system. There are two lungs in the human body. Though similar in appearance, they are not identical. Each lung is divided into the lobes. The right lung, which has three lobes, is slightly larger than the left one, because the latter has only two lobes. The lower lobe of the right lung is larger than that of the left one. The lungs are separated from each other by the mediastinum. The lungs are covered by a protective membrane called the pleura, a subserous elastic tissue and the parenchyma, the latter being the proper substance of the lungs. Each lung has the base, apex, two borders and three surfaces. They are conical in shape.

The lungs are housed in the chest cavity, or thoracic cavity. Human lungs are located in two cavities on either side of the heart. The posterior borders of the lungs are on each side of the spinal column. The anterior border is thin and overlaps the pericardium. The apex of the lung extends upward 3-4 centimeters above the level of the first rib. The base of the lung is located in the convex surface of the diaphragm. The diaphragm separates the lungs from the abdominal cavity, it having a very important role in the process of breathing.

The environment of the lungs being very moist, it makes them hospitable for bacteria. Many respiratory illnesses are the result of bacterial or viral infection of the lungs. Inflammation of the lungs is known as pneumonia; inflammation of the pleura surrounding the lungs is known as pleurisy.

But the lungs are very important in the body's defense against infection and other harmful environmental factors. While the nose is the first line of defense against inhaled harmful materials, the lungs provide the second line of defense. Inhaled particles (smoke, pollution) or infectious agents (bacteria, viruses) pass through the mouth or nose and lodge in the lungs.

Vital capacity is the maximum volume of air that a person can exhale after maximum inhalation; it can be measured with a spirometer. In combination with other physiological measurements, the vital capacity can help make a diagnosis of lung disease. Due to the excess capacity, it is possible for humans to live with only one lung, the other one compensating for its loss.

In infants the lungs are of a pale rose color, but later they become darker.

The pulmonary arteries carry deoxygenated blood from the right ventricle of the heart to the lungs. The pulmonary veins, on the other hand, carry oxygenated blood from the lungs to the heart, so it can be pumped to the rest of the body.

Ex. 5. Retell the article “Smoking and your Lungs” in Russian.

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