Respiratory System

What Is the Respiratory System?

The respiratory system is the organs and other parts of your body involved in breathing, when you exchange oxygen and carbon dioxide.

All the cells in your body need oxygen to work. As they take in oxygen, they release carbon dioxide, which is called a "waste gas." It goes into you bloodstream and gets carried to your lungs. You breathe it out when you exhale. 

This vital function is called "gas exchange," and your body is set up to do it automatically. 

Respiratory System Function 

Your respiratory system is a complex web of body parts that delivers oxygen to your cells. It also allows you to talk and smell. (Photo Credit: iStock/Getty Images)

Breathing is not the only job done by your respiratory system. Other tasks include: 

Warming up air so that it matches your body temperature 

Moisturizing air to the humidity level your body needs

Protecting your airways from things that might irritate or harm them 

Letting you smell and talk 

Respiratory System Parts

Your respiratory system is divided into two parts, upper and lower. 

Your upper respiratory tract is made up of: 

The parts of your lower respiratory tract are: 

Windpipe (trachea)

Diaphragm

Lungs

Bronchial tubes/bronchi

Bronchioles

Air sacs (alveoli)

Capillaries

Respiratory System and Circulatory System 

The circulatory system, also known as the cardiovascular system, moves blood around your body. It and your respiratory system work together to bring oxygen-rich blood to your cells. 

Breathing starts when you inhale air into your nose or mouth. It travels down the back of your throat and into your windpipe, which is divided into air passages called bronchial tubes.

For your lungs to perform their best, these airways need to be open.  They should be free from inflammation or swelling and extra mucus.

As the bronchial tubes pass through your lungs, they divide into smaller air passages called bronchioles. The bronchioles end in tiny balloon-like air sacs called alveoli. Your body has about 600 million alveoli.

The alveoli are surrounded by a mesh of tiny blood vessels called capillaries. Here, oxygen from inhaled air passes into your blood.

After absorbing oxygen, blood goes to your heart. Your heart then pumps it through your body to the cells of your tissues and organs.

As the cells use the oxygen, they make carbon dioxide that goes into your blood. Your blood then carries the carbon dioxide back to your lungs, where it’s removed from your body when you exhale.

Inhalation and Exhalation

Inhalation and exhalation are how your body brings in oxygen and gets rid of carbon dioxide. The process gets help from a large dome-shaped muscle under your lungs called the diaphragm.

When you breathe in, your diaphragm pulls downward, creating a vacuum that causes a rush of air into your lungs.

The opposite happens with exhalation: Your diaphragm relaxes upward, pushing on your lungs, allowing them to deflate.

How Does the Respiratory System Clean the Air?

Your respiratory system has built-in methods to keep harmful things in the air from entering your lungs.

Hairs in your nose help filter out large particles. Tiny hairs, called cilia, along your air passages move in a sweeping motion to keep the passages clean. But if you breathe in harmful things like cigarette smoke, the cilia can stop working. This can lead to health problems like bronchitis.

Cells in your trachea and bronchial tubes make mucus that keeps air passages moist and helps keep dust, bacteria and viruses, and allergy-causing things out of your lungs.

Mucus can bring up things that reach deeper into your lungs. You then cough out or swallow them.

Respiratory System Diseases

Respiratory infections are common illnesses. Children are especially likely to get them. They can affect your upper or lower respiratory tract. 

Upper respiratory infections include: 

Lower respiratory infections include: 

Bronchitis, an infection of your lungs that causes coughing and a fever 

Bronchiolitis, a lung infection that usually affects children 

Chest infection 

Pneumonia 

Respiratory infections are caused by viruses or bacteria entering your system. They're contagious, spread by sneezing, coughing, or touching things contaminated with germs.

You may have heard about RSV, which stands for respiratory syncytial virus. It's a common upper respiratory virus that usually isn't serious, but it can cause problems for older people and small children. 

Influenza, or the flu, isn't considered an upper respiratory virus, even though it can cause symptoms like coughing, a sore throat, and a runny nose. That's because the flu virus affects more than one system in your body.

Common diseases of the respiratory system include:

How to Take Care of Your Respiratory System

You can take steps to keep the parts of your respiratory system healthy and functioning well. They include: 

Respiratory System FAQs

How does the respiratory system work with the muscular system? 

Several muscles work with your respiratory system when you breathe. The main one is your diaphragm, which separates your lungs from your belly space. Muscles between your ribs, called intercostal muscles, and muscles in your belly area help out when you're breathing hard; for instance, when you're exercising. Muscles in your face, nose, and throat also help with breathing. And muscles in your neck and collarbone help you to inhale. 

Can you live without one lung?

Yes. Most people can manage with one lung, as long as it's healthy. 

What doctor specializes in the respiratory system?

Pulmonologists focus on problems with the respiratory system.