Breathing: It is something that most of us take for granted, but understanding how oxygen-rich air enters your lungs where it is exchanged for carbon dioxide is an important part of living with COPD. Let’s take a tour of the respiratory system and learn more about airway oxygen so you can see how respiration works.
The Respiratory System
The respiratory system is composed of specialized cells, tissues and organs, each with the purpose of helping you breathe. Breathing in airway oxygen is usually automatic, meaning the brain controls the respiratory process so it is involuntary—you do not have to think about breathing in and breathing out to breathe easily. The respiratory system works continuously (24/7) to maintain the right oxygen and carbon dioxide levels in your body so you can go about your daily life. When something disturbs the balance of oxygen and carbon dioxide levels, the respiratory system and other bodily systems work together to bring the body back to homeostasis, or a balanced state. If homeostasis cannot be restored or your body is experiencing difficulty getting adequate airway oxygen using the body’s normal compensatory mechanisms, medical attention may be required.
The Upper Respiratory System
The upper respiratory system consists of the nose, nasal cavity, pharynx (throat) and larynx (voice box).
Breathing begins as you inhale air from the environment through the nostrils of your nose or through your mouth, where the air is filtered, warmed and humidified in the nasal cavity. The air then passes through the pharynx — a passageway for both air and food – and into the larynx, which also functions to prevent food from entering the lower respiratory system. Upon entering the lower respiratory system, your body begins the process of separating airway oxygen from the mix of gases in the air.
The Lower Respiratory System
The major structures of the lower respiratory system include the trachea (windpipe), bronchi, bronchioles, alveoli, and lungs.
After the air leaves the larynx, it passes through the trachea, which is composed of firm, C-shape cartilage rings that give the trachea its rigidity. This is important because it allows the trachea to remain continuously open. The trachea is approximately 4 inches long and 1 inch in diameter and is very flexible in nature. Similar to the nasal cavity, it helps filter, warm and humidify the air that passes through it. before the air is fully filtered into airway oxygen.
As the air leaves the trachea, it flows into the bronchi. One bronchus leads to the right lung and the other to the left. Like the trachea, the bronchi consist of firm, C-shaped cartilage, providing rigidity and support to the airways. The air continues through the bronchi – which further subdivides into smaller bronchioles – until it reaches the alveoli, commonly referred to as air sacs. It is in the alveoli that the gas exchange of airway oxygen takes place.
The alveoli are tiny structures within the lungs measuring approximately 200 micrometers, or just a fraction of a centimeter. These tiny alveoli are bunched together in grape-like clusters to form alveolar sacs. On the surface of the alveoli are networks of tiny blood vessels called capillaries. It is through these tiny capillaries that airway oxygen from the air you inhale diffuses into the blood stream as a result of partial pressure. At the same time, carbon dioxide, the waste product of respiration, moves from the capillaries into the alveoli and out through the airways of the lungs where it is blown out with the next exhalation.
Bringing it all Together
After absorbing airway oxygen, your oxygenated blood leaves the lungs and travels through the pulmonary veins to the left side of the heart. The left side of your heart has an important purpose; it pumps oxygen-rich blood to the rest of your body in order to provide oxygen to the cells of your tissues and organs. Concurrently, as your cells absorb and utilize the provided oxygen, carbon dioxide is produced and absorbed into your blood stream. The oxygen deficient, carbon dioxide-rich blood is carried back to the right side of the heart through the superior vena cava and the inferior vena cava, two large veins located above and below the heart muscle. Finally, your blood returns to the lungs through the pulmonary artery, where carbon dioxide diffuses across the capillaries of the alveoli and is removed from the body when you exhale.
Why the Proper Inhalation and Absorption of Airway Oxygen Matters
If you are unable to inhale sufficient airway oxygen, or if your blood or cells are incapable of transferring or using oxygen properly, you could become hypoxic, with low oxygen in your tissues, or hypoxemic, with oxygen in your blood. These two conditions are caused by oxygen deprivation and are extremely hazardous to your health if allowed to continue untreated. If you have COPD, lung disease or another breathing condition like asthma, your body may not be able to absorb airway oxygen the way it is supposed to, and it may be unable to diffuse sufficient amounts into your blood or your tissues. Without the oxygen your cells and tissues need to function properly, your health could be at significant risk.
How Oxygen Concentrators Can Help Increase Your Airway Oxygen
When you are not able to inhale adequate airway oxygen, oxygen therapy may be prescribed to help you breathe better and improve your oxygenation and perfusion. Oxygen therapy can help improve your quality of life, particularly when your oxygen treatments are provided by a small, lightweight portable oxygen concentrator. Portable oxygen concentrators are easy-to-use, small in size and lightweight enough to carry, offering you better mobility, freedom and independence. If you are experiencing reduced airway oxygen as a result of lung disease or a breathing condition, an oxygen concentrator can provide much needed relief.
For more information about airway oxygen and how the blood flows through the body, talk to your primary care provider. And while you’re there, talk to your health care provider about whether oxygen therapy is right for you. There is no need to allow reduced airway oxygen to take over your life.
 NHLBI. The Respiratory System. Last Updated 7/17/2012.
 Noah Lechtzin, MD, MHS. Exchanging Oxygen and Carbon Dioxide.Merck Manuals. Accessed 6/29/2017.