The conducting zone is the part of the airway responsible for moving air into the lungs while removing particulates. It receives air from the nose and mouth, which filter and warm it, before routing it to the respiratory zone, where actual gas exchange takes place. In this process, the oxygen in the air is traded with carbon dioxide from the blood, re-oxygenating the blood so it can circulate back through the body. Each part of the airway performs essential functions, and can be vulnerable to different kinds of medical problems.
This area of the respiratory tract starts at the trachea and moves into the bronchi, the branching structures that deliver air into the lungs. They break up into individual bronchioles, at which point the air passes into the respiratory zone. The tissues in the conducting zone are lined with small hair known as cilia which beat upwards to force particulate materials up and out of the airways. Additionally, mucus-producing cells create a layer of mucus to trap particles so they can be more easily snagged and removed by the cilia.
Two separate functions are performed by the conducting zone. One is additional filtration of the air. Organisms could infect the lungs or air passages, potentially creating a serious problem for the patient. Most can be trapped and removed in this area, reducing the chances that someone will develop an infection and keeping the airways clear. Any remaining organisms may not be present in large enough numbers to grow and spread, or can be mopped up by the immune system.
Particles in the air can also potentially create issues. They may irritate the airways and could trigger allergic responses, or become embedded and potentially create lesions. Long-term exposure to certain particulates can also contribute to the development of cancer in the lungs and respiratory tract. The conducting zone works to keep the air clean and clear so people can breathe safely.
Additionally, it allows air to pass into the lungs, maintaining a steady supply of oxygen for the blood, while also routing waste products upon exhalation. The conducting zone coordinates with the rest of the respiratory tract to keep the patient’s blood oxygenated. This includes working with the digestive tract to control the esophagus and trachea to reduce the risk of inhaling food products or swallowing air. Muscle control, automatic responses, and nerve signaling all play a role in keeping the respiratory and digestive tracts working smoothly.