How the Respiratory System Works

What Is the Respiratory System? How Does It Work?

Many of us take the respiratory system for granted, counting on our lungs to do the vital work of oxygenating our entire body. However, if you stop to think about how the oxygen gets from your lungs into your bloodstream, you might find yourself thinking, “How does the respiratory system work?” Understanding what is the function of the respiratory system and what to do if it is not functioning properly is an essential part of taking good care of yourself. Read on to learn more about your pulmonary system, respiratory system organs and proper respiratory system function.

Understanding Respiratory System Function

The respiratory system is the network of organs and tissues that help you breathe. It includes your airways, lungs and blood vessels. The muscles that power your lungs are also part of the respiratory system. These parts work together to move oxygen throughout the body and clean out waste gases like carbon dioxide.

The respiratory system has many functions. Besides helping you inhale (breathe in) and exhale (breathe out), it:

  • Allows you to talk and to smell.
  • Warms air to match your body temperature and moisturizes it to the humidity level your body needs.
  • Delivers oxygen to the cells in your body.
  • Removes waste gases, including carbon dioxide, from the body when you exhale.
  • Protects your airways from harmful substances and irritants[1]

How Does the Respiratory System Work?

In order to fully understand how the respiratory system works, let’s start with basic respiratory function. Air comes into the body through the nose or mouth, and enters the airways. Airways are the tubes that carry air into our lungs. As they branch out, they become smaller and smaller, and eventually connect to parts of the lungs called alveoli, small air sacs where fresh oxygen from the air is exchanged for carbon dioxide in the blood. This oxygen is then taken through the blood to the rest of your body, where it is used to produce energy.[2]

The respiratory system has many different parts that work together to help you breathe. Each group of parts has many separate components.

Your airways deliver air to your lungs. Your airways are a complicated system that includes your[1]:

  • Mouth and nose: Openings that pull air from outside your body into your respiratory system.
  • Sinuses: Hollow areas between the bones in your head that help regulate the temperature and humidity of the air you inhale.
  • Pharynx (throat): Tube that delivers air from your mouth and nose to the trachea (windpipe).
  • Trachea: Passage connecting your throat and lungs.
  • Bronchial tubes: Tubes at the bottom of your windpipe that connect into each lung.
  • Lungs: Two organs that remove oxygen from the air and pass it into your blood.

From your lungs, your bloodstream delivers oxygen to all your organs and other tissues.

Muscles and bones help move the air you inhale into and out of your lungs. Some of the bones and muscles in the respiratory system include your[1]:

  • Diaphragm: Muscle that helps your lungs pull in air and push it out.
  • Ribs: Bones that surround and protect your lungs and heart.

When you breathe out, your blood carries carbon dioxide and other waste out of the body. Other components that work with the lungs and blood vessels include[1]:

  • Alveoli: Tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place.
  • Bronchioles: Small branches of the bronchial tubes that lead to the alveoli.
  • Capillaries: Blood vessels in the alveoli walls that move oxygen and carbon dioxide.
  • Lung lobes: Sections of the lungs — three lobes in the right lung and two in the left lung.
  • Pleura: Thin sacs that surround each lung lobe and separate your lungs from the chest wall.

Some of the other components of your respiratory system include[1]:

  • Cilia: Tiny hairs that move in a wave-like motion to filter dust and other irritants out of your airways.
  • Epiglottis: Tissue flap at the entrance to the trachea that closes when you swallow to keep food and liquids out of your airway.
  • Larynx (voice box): Hollow organ that allows you to talk and make sounds when air moves in and out.

How Does the Respiratory System Work with Your Body?

The respiratory system is important because it helps you oxygenate your entire body, but how does the respiratory system work with your other systems and organs? Your respiratory system connects to and interacts with every other part of your body. Your circulatory system, digestive system, endocrine system, immune system, muscular system, nervous system, reproductive system, skeletal system and more, all work with your respiratory system to help keep your body working as it should. Each system is reliant on other systems to help keep your organs healthy and working correctly. Without the circulatory system, for example, the oxygen you inhale could not be circulated throughout the body. Without the muscular system, you would not be able to inhale and exhale. If one system in the body fails, so do many of the others. In the case of the respiratory system, however, no other system can function without the necessary oxygen being delivered to every cell in the body. Without a functioning respiratory system oxygenating the body, all other systems begin to fail immediately.[2]

Respiratory System Facts

In order to fully grasp the importance of respiratory system function, here are a few respiratory system facts that may surprise you.

  • Your lungs have a huge amount of surface area. If opened up and laid flat, an adult lung would be about the size of a tennis court.[3]
  • Your lungs are different sizes. The right lung is larger than the left lung in order to accommodate your heart.[3]
  • When the alveoli are filled with air, your lungs are the only organs in your body that can float.[3]
  • People breathe an average of 13 pints of air each minute.[3]
  • Women and children have a higher breathing rate than men.[3]
  • About 70% of waste is eliminated through your lungs via breathing.[3]
  • You exhale up to 17.5 milliliters of water each hour, and up to four times that when you exercise.[3]
  • While oxygen is essential to the health of our cells, the air we breathe contains just 21% oxygen, and healthy bodies use only about 5% of that.[3]
  • Some air never leaves your lungs. That air keeps your alveoli and smaller airways open enough to allow the next breath to come more easily.[5]

What Is the Function of the Respiratory System?

Most of us understand that the main respiratory system’s function is breathing, but you may still find yourself asking, “What is the function of the respiratory system exactly?” The respiratory system diagram above can help you understand how each of the respiratory system organs and respiratory system parts work together within the pulmonary system to help you clearly understand the purpose of this vital system within the body.

While breathing is the short answer to “What is the function of the respiratory system?” ultimately, the respiratory system is designed to pull oxygen from the air via the lungs, where it enters the bloodstream, while expelling gathered carbon dioxide out of the body. In this way, the respiratory system organs help distribute oxygenated blood to the rest of the body. This is, of course, why proper respiratory system function is vital to the body’s health. Oxygen is essential for the cells, and the body as a whole, to function correctly and stay alive and healthy.[1] On the other hand, when respiratory function is impacted by damage or disease, the blood retains excessive carbon dioxide, which is a byproduct of cell metabolism. This excess carbon dioxide can increase blood pressure, heart rate, breathing and blood flow to vital organs, and restrict blood flow to the extremities.[6]

People who suffer from chronic lung disorders have something wrong with one or more respiratory system parts, which impacts overall respiratory function. This prevents their body from getting the oxygen it needs to function properly and can also cause excess carbon dioxide to build up in the bloodstream, all of which causes significant problems for that person’s health overall.

If you or a loved one have a chronic lung disorder, your doctor may prescribe a number of different therapy options to help you breathe better and get the oxygen you need. If your doctor prescribes oxygen therapy, you may benefit from using a portable oxygen concentrator such as the Inogen One to help improve your respiratory function as much as possible without limiting your daily life.

Respiratory Function and Inogen

If you are living with a chronic lung condition like COPD, and your respiratory system isn’t working the way it should, Inogen can help. The Inogen One portable oxygen concentrator system is designed for portable and stationary oxygen therapy. For most people with COPD and other chronic lung disorders, the breathlessness and other physical symptoms cause a significant impact on daily activities. In the past, oxygen therapy meant being tethered to an oxygen tank or stationary concentrator, requiring that you stay in one place or carry heavy tanks that need to be refilled regularly. Inogen One offers a solution for oxygen at home or away, day or night.

With Inogen One, you can get your oxygen at home or away with a portable system that
requires no refills or heavy tanks, as long as you are connected to a battery or AC power source. This compact and lightweight system travels easily in a pack or on wheels, and it pulls oxygen continuously from the atmosphere. The Inogen One portable oxygen concentrators are powered by rechargeable battery or any AC or DC power source, so you can use it at home or on the go.

Living with COPD and other chronic lung conditions requires some adjustments, but it should not mean missing out on your life. With Inogen, you can enjoy freedom, independence and mobility while still receiving the benefits of your oxygen therapy. Talk to your doctor and get the respiratory system facts about your lung disorder to learn how an Inogen One System can help you today. Contact us for more information.

Frequently Asked Questions

What are the five main functions of the respiratory system?[5]

Your respiratory system performs five main functions to keep your body healthy and working properly. While some may seem obvious, others may not have occurred to you. 

  1. Pulmonary ventilation, also known as breathing. Inhaling and exhaling air is the most obvious and most important function of the respiratory system. During this process, air is warmed and achieves the proper humidity level, and it is also filtered to remove harmful irritants.
  2. The gas exchange between the lungs and the bloodstream allows oxygen to enter your capillaries from your lungs and carbon dioxide to leave your capillaries via your lungs.
  3. The delivery of gasses to and from your cells. Your red bloodstream carries oxygenated blood throughout the body to your tissues, while carbon dioxide leaves your tissues, entering your bloodstream to be carried to the lungs.
  4. Vibrating your vocal cords so that you are able to speak.

Working with your nervous system to make the process of olfaction (or smelling) possible.

What is the main function of the respiratory system?

The primary respiratory system function is to take in oxygen and expel carbon dioxide. This occurs through the breathing process, when red blood cells collect the oxygen we have breathed in through the lungs and carry it throughout our bodies, while red blood cells also collect carbon dioxide and bring it back to our lungs where it can be exhaled.[1]

What happens when you breathe?

In breathing (also called pulmonary ventilation), air is inhaled through the nasal and oral cavities (the nose and mouth). It moves through the pharynx, larynx, and trachea into the lungs. Then air is exhaled, flowing back through the same pathway. Changes to the volume and air pressure in the lungs trigger breathing. During normal inhalation, the diaphragm and external intercostal muscles contract and the ribcage elevates. As the volume of the lungs increases, air pressure drops and air rushes in. During normal exhalation, the muscles relax. The lungs become smaller, the air pressure rises, and air is expelled.[5]

Where does gas exchange occur in the lungs?

How does the respiratory system work to get oxygen into the body and carbon dioxide out of the body? The exchange of gases in the lungs takes place between the alveoli and capillaries. The capillaries and alveoli share a membrane through which oxygen can pass from the alveoli into the capillaries and carbon dioxide can pass from the capillaries into the alveoli. This gas exchange creates oxygenated blood, which is then circulated throughout the body via the bloodstream, while tissues are able to expel carbon dioxide to be carried via the bloodstream back to the lungs to be exhaled.[6] 

Is the heart part of the respiratory system?

The heart is not part of the respiratory system, though it does play a key role in working with the respiratory system. The heart is actually the most important player in the circulatory system, helping to pump blood throughout the body. So, how does the respiratory system work with the heart? The circulatory system works very closely with the respiratory system, helping to bring oxygenated blood to every part of the body. Without the heart, the oxygen needed by each of your cells would not be delivered, and the waste carbon dioxide created by the body’s processes would not be delivered to the lungs where it can be exhaled. So, while the heart is not a part of the respiratory system, it is essential to helping the respiratory system work correctly.[4]

How do chronic lung diseases affect the respiratory system organs?

Chronic disease in the pulmonary system can cause irritation, inflammation and permanent damage in the respiratory system parts. These diseases are lasting and progressive, causing difficulty breathing. While chronic lung diseases like asthma and chronic bronchitis begin as irritation and inflammation in the airways, they can eventually cause permanent damage. Chronic lung diseases like COPD and lung cancer, on the other hand, tend to progress faster and always result in damage to the lungs.[7]


  1. “Respiratory System: Functions, Facts, Organs & Anatomy.” Cleveland Clinic, Cleveland Clinic, 24 Jan. 2020,
  2. Smith, Courtney. “Anatomy and Physiology: The Relationships of the Respiratory System.” Visible Body 3d Human Anatomy, 16 Nov. 2012,
  3. Ribeiro, Marta. “8 Fun Facts About Lungs.” Pulmonary Hypertension News, BioNews Services, LLC, 7 Sept. 2018,
  4. “5 Functions of Respiratory System: Respiratory Anatomy.” Visible Body, Visible Body, Accessed 5 July 2020,
  5. What Is Residual Volume? (
  6. Martin, Laura J. “Gas Exchange .” MedlinePlus, U.S. National Library of Medicine, 12 July 2018,

Additional Sources

View all of our Inogen One Systems   See what Inogen One customers are saying  

Inogen Call For Support View Cart
Request a FREE Info Kit