Text C. The LungsThe lungs are the

Text C. The Lungs
The lungs are the main organs of the respiratory system. There are two lungs in the human body located in the lateral cavities of the chest. The lungs are separated from each other by the mediastinum. The lungs are covered with the pleura. They are conical in shape. Each lung has the base, apex, two borders and three surfaces.
The lung has the apex extending upward 3-4 centimetres (cm) above the level of the first rib.
The base of the lung is located in the convex (выпуклый) surface of the diaphragm.
The posterior borders of the lungs are on each side of the spinal column. The anterior borders thin and overlap (перекрывать) the pericardium.
The weight of the lungs varies according to many conditions. In the adult male the weight of the lungs is about 1,350 gr. The right lung is about 15% heavier than the left one. The vital capacity of the lungs is 3.5-4 liters in the male and it is 3-3.5 liters in the female.
The right lung consisting of three lobes is heavier than the left one because the latter consists only of two lobes. The lower lobe of the left lung is larger than the upper one.
In infants the lungs are of a pale rose colour, but later they become darker.
The lung is coveres with an external serous coat, i.e. with visceral layer of the pleura. The parenchyma or proper substance of the lungs consists of the bronchial tree with elastic tissue and vessels.