Lung

The lung is a paired organ of the respiratory system surrounded by a serous membrane (see Pleura), located in the chest cavity on both sides of the heart. The lungs are elastic air-carrying organs that can expand and contract with the movements of the ribs and diaphragm during breathing. Atmospheric air enters the lungs through the airways: the nasal cavity, pharynx, larynx and trachea, which, in turn, is divided into two bronchi (see Bronchi), and the latter branch in the lungs to the smallest bronchioles. Bronchioles are also divided into even smaller branches, which end in air bubbles (see Alveoli), where gas exchange occurs in the human body (see figure). Oxygen absorbed from the atmosphere diffuses into the blood, and carbon dioxide entering from the bloodstream through the pulmonary capillaries diffuses into the alveoli; in each case, during the process of gas exchange, the concentration of one or another component involved in the respiration process decreases, and the other increases (see Pulmonary circulation). The total lung capacity of an adult male is approximately 5.5 liters, but only 500 ml of air is exchanged during normal breathing (see also Residual Lung Volume). Other functions performed by the lungs include the removal of water from the body: it is important for maintaining normal water balance in the body and its thermoregulation.

Lung: structure and functions

The lungs are a paired organ of the respiratory system, located in the chest cavity on both sides of the heart and surrounded by a serous membrane (pleura). They are elastic air-carrying organs that can expand and contract under the influence of movements of the ribs and diaphragm during breathing.

Atmospheric air enters the lungs through the airways: the nasal cavity, pharynx, larynx and trachea, which, in turn, is divided into two bronchi. The latter branch in the lungs to the smallest bronchioles, which are also divided into even smaller branches ending in air bubbles (alveoli). In the human body, gas exchange occurs in the alveoli, in which oxygen absorbed from the atmosphere diffuses into the blood, and carbon dioxide, coming from the bloodstream through the pulmonary capillaries, diffuses into the alveoli.

During gas exchange, the concentration of oxygen increases and carbon dioxide decreases. In addition, the lungs perform other functions, including removing water from the body, which is important for maintaining normal water balance in the body and its heat regulation.

The total lung capacity of an adult male is approximately 5.5 liters, but only 500 ml of air is exchanged during normal breathing. This is due to the fact that the lungs can store a significant amount of air, which does not participate in gas exchange and is called residual lung volume.

It should be noted that the lungs can be susceptible to various diseases, for example, chronic obstructive pulmonary disease (COPD), bronchial asthma, pneumonia and others. Therefore, it is important to monitor the condition of the respiratory system and consult a doctor if any symptoms occur.

The lungs are a paired organ that is located on both sides of the heart in the thoracic band. They are triangular in shape and covered with a serous membrane called the pleura. Lung tissue consists of 60-70% connective tissue, bronchioles and reticular tissue, the rest is epithelial cells intended for gas exchange.

The lungs have a two-story structure. The lungs are divided into large and small airways. The large airways include the nasopharynx, trachea and bronchus. Small airways, including bronchioles and alveoli.

In an adult man, each lung holds about 5 liters of air. However, during normal breathing, only 0.5 liters of air are exchanged because the remaining 4.5 liters of air remains inside the lungs, this is called residual lung volume. Residual lung volume is necessary to avoid collapse of the alveoli during breathing. In hypoventilation conditions or breath holding, difficulty in inhaling occurs as the lungs try to remove the 0.5 liter of carbon dioxide remaining inside. This is important to consider when performing surgery, ventilation and resuscitation in case of shock.