Question

Расскажите, какие процессы происходят в легочных альвеолах.

Answer 1

Альвеолы участвуют в акте дыхания, осуществляя газообмен с легочными капиллярами.

Answer 2

Processes in the Pulmonary Alveoli

The pulmonary alveoli are tiny air sacs located at the end of the respiratory bronchioles in the lungs. These alveoli are responsible for the exchange of oxygen and carbon dioxide between the air and the bloodstream. Let's explore the processes that occur in the pulmonary alveoli:

1. Pulmonary Ventilation: The process of breathing involves the movement of air into and out of the lungs. During inhalation, the diaphragm and intercostal muscles contract, expanding the thoracic cavity and causing air to enter the lungs. During exhalation, these muscles relax, and the thoracic cavity decreases in size, allowing air to be expelled from the lungs.

2. Gas Exchange: The primary function of the pulmonary alveoli is to facilitate the exchange of gases between the air and the bloodstream. Oxygen from the inhaled air diffuses across the thin walls of the alveoli into the surrounding capillaries, where it binds to hemoglobin in red blood cells. At the same time, carbon dioxide, a waste product of cellular respiration, diffuses from the capillaries into the alveoli to be exhaled.

3. Surfactant Production: The alveoli are lined with a thin layer of fluid that helps to reduce surface tension. This fluid contains a substance called surfactant, which is produced by specialized cells known as type II alveolar cells. Surfactant reduces the surface tension of the fluid, preventing the alveoli from collapsing and facilitating the exchange of gases.

4. Immune Defense: The alveoli play a crucial role in the immune defense of the respiratory system. They are lined with specialized cells called alveolar macrophages, which are responsible for engulfing and removing foreign particles, such as bacteria and dust, that may be present in the inhaled air.

5. Regulation of Blood Flow: The pulmonary alveoli help regulate blood flow through the lungs. When alveoli are well-ventilated with oxygen, the surrounding blood vessels dilate, allowing for increased blood flow and optimal gas exchange. Conversely, when alveoli are poorly ventilated, the blood vessels constrict, redirecting blood flow to areas with better ventilation.

In summary, the processes that occur in the pulmonary alveoli include pulmonary ventilation, gas exchange, surfactant production, immune defense, and regulation of blood flow. These processes are essential for maintaining proper respiratory function and ensuring the exchange of oxygen and carbon dioxide between the air and the bloodstream.