The respiratory system, a complex network of organs and tissues, enables us to breathe and maintain a vital connection with our surroundings. Comprised of the respiratory channel, lungs, respiratory muscles, and nerve structures controlling functions, this system works in harmony with the blood and cardiovascular system to transport oxygen and remove carbon dioxide.
Divided into upper and lower parts, the respiratory system includes the nasal cavities, nasopharynx, stomatopharynx, gorge, air-vessel, and extra and intrapulmonary air tubes. To function normally, the respiratory system must deliver approximately 250-280 ml of oxygen per minute under relative rest conditions and expel a similar amount of carbon dioxide gas.
As we constantly interact with atmospheric air, our respiratory system faces potential threats such as microorganisms, viruses, and harmful chemical substances. These agents can penetrate the human body and cause various diseases, some of which can spread rapidly or become epidemics, such as influenza, acute respiratory viral infections, and tuberculosis. Air pollution caused by chemicals of technogenic origin, like hazardous industries and motor vehicles, poses a significant threat to human health.
One of the primary functions of the respiratory tract is to facilitate airflow from the atmosphere into the human lungs and vice versa. The respiratory system also plays a crucial role in filtering air, particularly in the upper airway, where up to 90% of dust particles settle on the mucous membrane. Smaller particles, however, can penetrate deeper into the airway, with bronchioles and alveoli being susceptible to particles ranging from 1-10 microns in diameter. The removal of dust particles is facilitated by the flow of mucus, which originates from the secretion of chalice cells and mucus-forming glands in the respiratory tract, as well as the fluid filtered from the interstitium and hemocapillaries of the air tubes walls and lungs.
In addition to air purification, the respiratory system is responsible for warming and humidifying inhaled air. As the atmospheric air comes into contact with the warm surface of the respiratory tract, it heats up to approximately 37°C, even when inhaling cold air. The air removed from the lungs gives up to 30% of its heat to the mucous membranes. Furthermore, as the breathing air flows through the airways and alveoli, it becomes 100% saturated with water vapor, resulting in a water vapor pressure in the alveolar air of about 47 mm Hg.
The respiratory system’s intricate design and functions enable us to breathe efficiently, maintain our overall health, and adapt to various environmental conditions. Understanding the importance of this system and the potential threats it faces can help us appreciate the marvels of the human body and inspire us to take better care of our well-being.
