Lungs (pulmones) are the respiratory organs, in which the blood enriches with oxygen and carbon dioxide is released from it. Admission to the lungs of air and bringing it outside is provided by the respiratory movements of the chest, diaphragm and contractile ability of the lung itself. In addition to the main function of gas exchange , the lungs perform a secretory-excretory function and participate in metabolism.
Anatomy and Histology
Fig. 1. Human lungs: 1 - trachea ;
2 and 4 - the left lung (2 - the upper lobe, 4 - the lower lobe); 3 - rib surface; 5 - heart tenderloin; 6 - diaphragmatic surface; 7, 9, and 11 — right lung (7 — lower lobe, 9 — medium, 11 — upper lobe); 8 - oblique groove; 10 - horizontal groove.
The lungs (Fig. 1) are located in the chest cavity on both sides of the heart and large vessels and are covered with a serous membrane - the pleura (see). Between the pleural sacs, which enclose the lungs, the mediastinum is located (see). The lungs have a cone-shaped shape with a base directed downwards towards the diaphragm and with a rounded tip jutting out 2–3 cm above the clavicle, and behind it reaching the level VII of the cervical vertebra. The lower border of the lungs behind the paravertebral line comes to XI, along the middle axillary to VIII, and from the front along the midclavicular to the VI rib. The right lung has a larger volume than the left, it is shorter and wider, since the right dome of the diaphragm is higher than the left. In the lungs there are three surfaces: costal, diaphragmatic (base) and internal (medial). They are delimited by sharp lower and front edges. At the anterior margin of the left lung, a heart tenderloin is formed, bounded by the lower tongue. Behind the transition of the costal surface in the medial rounded and lies in the pulmonary groove of the chest. The gates of the lungs are located on the medial surface, through which the bronchus, the pulmonary artery and nerves enter the lungs and two pulmonary veins and lymphatic vessels exit. They form the root of the lung. At the root of the right lung artery lies below the bronchus, and in the left - above it. The pulmonary veins are located below the artery and bronchus. The right lung furrows are divided into three lobes: upper, middle and lower; left - in two: upper and lower. According to the division of the lung into lobes, the main bronchus is divided into lobar bronchi, the latter - into segmental ones that are included in the segments of the lung. The bronchopulmonary segment is the area of the lung that is more or less completely separated from the adjacent areas by connective tissue septa with veins that pass through them. This is the branch area of the bronchus of the 3rd order in the branch of the pulmonary artery. Each lung has 10 segments (no-PNA).
Fig. 6. Lung segments (A and B - right, C and D - left): 1 - apical segment; 2 - posterior segment; 3 — front segment; 4 - the lateral segment (right lung) and the upper reed segment (left lung); 5 - medial segment (right lung) and lower reed segment (left lung); 6 - apical segment (lower lobe); 7 - basal medial segment; 8 - basal anterior segment (7 and 8 in the left lung in most cases have a common bronchus); 9 - basal lateral segment; 10 - basal posterior segment.
Segments (fig. 6) consist of pulmonary lobules. Each lobule includes a lobular bronchus with a diameter of about 1 mm, formed as a result of repeated branching of the segmental bronchus. The lobules are located in 2–3 rows around the periphery of the lung and are separated by interlobular connective tissue. It ensures the mobility of the lobules during respiratory movements. Lobular bronchus is divided into terminal (terminal) bronchioles. The bronchial tree consists of large and small bronchi and terminal bronchioles. The air moves through them when inhaling and exhaling, but there is no gas exchange between the blood and the air. The terminal bronchioles give rise to respiratory (respiratory) bronchioles. In their walls there are protrusions - alveoli. Respiratory bronchioles branch and end with alveolar passages and alveoli. All these formations form the alveolar tree, or the respiratory parenchyma of the lungs. Its functional-anatomical unit is an acinus (bunch), formed by the branches of one respiratory bronchiole. The diameter of the alveoli of an adult person on average 0.2-0.25 mm, they are closely adjacent to one another. Their inner surface is lined with a single-layered flat alveolar epithelium lying on the basement membrane. Outside it is adjacent to the blood capillaries, passing in the interalveolar septa, in which there are many elastic, reticulin and collagen fibers. The blood capillary is bordered by several alveoli, which creates optimal conditions for gas exchange.
The lungs are vessels of the small and large circles of blood circulation. The small circle vessels include the branches of the pulmonary artery that carry venous blood into the lungs and the tributaries of the pulmonary veins that carry arterial blood from the lungs to the left atrium. The bronchi and the lung parenchyma feed the bronchial arteries - the branches of the thoracic aorta, venous blood flows through the bronchial veins into the unpaired and semi-unpaired veins. In the lungs arteriovenous anastomoses are found in large numbers. Lymphatic capillaries and vessels form superficial and deep networks and plexuses in the lungs. Lymphatic outflow occurs in the pulmonary, bronchopulmonary and upper and lower tracheo-bronchial lymph nodes located along the bronchi, at the root of the lung and in the split of the trachea. The lungs are innervated by the wandering nerves and branches of the sympathetic trunks that form the plexuses in the lungs along the vessels and bronchi.
Physiology - see Breath .
Pneumomycosis - see Pneumomycosis .
Pneumosclerosis - see Pneumosclerosis .
Emphysema - see Emphysema .
Echinococcus of the lungs - see above - Parasites of the lungs. See also Echinococcosis .
The lungs (pulmones) are paired respiratory organs located in the chest cavity in the serous bags of the pleura (Fig. 1-3).
Anatomy and Histology
Features of the structure of the lungs in children
Lung research methods
Clinic and treatment
Radiodiagnosis of diseases and injuries
Classification, clinic and treatment
Abscess and gangrene of the lungs
Radiation damage to the lungs