From Your Nose to Your Os: Understanding Your Respiratory System

From Your Nose to Your Os: Understanding Your Respiratory System

Asia Muhammad, ND Asia Muhammad, ND
4 minute read

The human respiratory system functions to pull in oxygen-rich air that is utilized in cells across the body to produce cellular energy. Our lungs are the prime organ responsible for oxygen exchange, but they’re not the only ones involved.

Beyond the lungs, our respiratory system includes our nose, parts of our throat called the oropharynx and larynx, trachea, and smaller branching sections called bronchi, bronchioles, and alveoli. When we inhale air into our nose, it is transported through the oropharynx and larynx, down the trachea, through the bronchi, and into the smaller branching bronchioles. At every step on this journey, your body is taking steps to protect and optimize your respiratory health:

  • Hair in our noses traps large particles such as dust, allergens, and bacteria as we inhale. Some particles are too small for nasal hairs to capture.

  • Mucus in the trachea, bronchi, and bronchioles traps particles that escape the nasal hairs. Immune cells called IgA are also present in the mucus of the lungs. They act as security guards to ensure harmful external agents are captured and eliminated.

The Main Stage for Oxygen Exchange

Our alveoli comprise the majority of our lung volume and are where oxygen exchange takes place. They are small air sacs that function to exchange gasses with blood, either oxygen-rich air that we breathe in for the body or elimination of carbon dioxide gas which we exhale. The sheer number of alveoli present in the lung denotes their importance. It is estimated that the human lung contains over 400 million alveoli. This number changes based on the size of the lungs, which does vary from person to person.

Before air reaches the alveoli, it must be filtered through nasal hairs and mucus. After passing through the upper respiratory tract filtration steps, the alveoli have their own filtration mechanism in place. Not only do alveolar cells secrete factors to protect the lung, but they also act as a physical barrier, protecting the body from possible inhaled toxins. The alveolar network of cells participates in lung defense through the secretion of chemical factors that control the presence of bacteria. They can also generate a larger immune response to defend the lungs against noxious inhaled agents.

The respiratory system is often referred to as a respiratory tree. Visually the tree trunk would represent the oropharynx and larynx, the many branches represent the bronchi and bronchioles, and the numerous leaves represent the alveoli. Our lungs can be visualized as two upside-down trees working to exchange air from our environment efficiently.

Environmental Lung Exposure

While we can appreciate the natural defenses of our respiratory system and the magic that happens in our alveoli, it’s important to acknowledge the many environmental airborne toxins (like cigarette smoke, exhaust smoke from cars, and other pollutants) that can be detrimental to lung health. Literature consistently reveals that the chemicals in the air negatively affect our lung health by creating increased oxidative stress. While breathing is effortless for most people, some endure respiratory hardships due to long-term exposure to environmental air toxins.

Many noxious agents harm our respiratory system. Some are common pollutants that we inhale daily depending on where we work and live, while others are insidious harmful agents that can be very toxic to our lungs, even in small amounts. Air filtration systems may not always be sufficient to properly extract mold toxins, exhaust pollutants, and other air particles from the air we breathe.

Cigarette smoke is just one well-documented example of an environmental irritant that damages our lungs and can create chronic pulmonary inflammation. It’s important to note that tobacco smoke not only affects our lung cells but has also been demonstrated to negatively affect our skin and nose, as well as alter our lung immune response.

This post kicks off a 4-part series in which we will delve into common environmental air pollutants and ways we can protect our lungs from inhalation of these pollutants. Another common and controversial air toxin comes from mold. Our next series will focus on mold toxins (also known as mycotoxins) and how they affect our respiratory system as a whole.

About the Author

Asia Muhammad, ND, is a Doctor of Naturopathic Medicine and an expert in functional medicine and personalized health. She specializes in gastroenterology, mind-body medicine, and stress management and has received additional training in mind-body therapies. Learn more at or follow Dr. Asia on Instagram.

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