Respiratory System

What is the respiratory system?

Your respiratory system is the organs and structures in your body that allow you to breathe. It includes your lungs, nose, mouth and the tubelike structures (airways) that connect them. You also have muscles and blood vessels that support your respiratory system, and ribs to protect it. These parts work together to bring oxygen into your body when you inhale and get rid of carbon dioxide when you exhale.

What is the main function of your respiratory system?

The main function of your respiratory system is to pull in oxygen for your body’s cells and get rid of carbon dioxide, a waste product. You do this by breathing in and out and through gas exchange between the small air sacs of your lungs (alveoli) and the blood vessels running nearby. Your respiratory system also:

• Warms and adds moisture to the air you breathe in. Your respiratory system warms the air to match your body temperature. It moisturizes the air to bring it to the humidity level your body needs.
• Protects your body from particles you breathe in. Parts of your respiratory system can block harmful germs and irritants from getting in — or push them out if they do get in.
• Allows you to talk. Air vibrates your vocal cords, which makes sounds.
• Helps you smell. Breathing in air moves its molecules past your olfactory nerve, which sends messages to your brain about the way something smells.
• Balances level of acidity in your body. Too much carbon dioxide lowers your blood’s pH, making it acidic. By removing carbon dioxide, your respiratory system helps maintain the acid-base balance in your body.

What are the parts of the respiratory system?

The main organs of your respiratory system are your lungs. But your respiratory system has many different parts that work together to help you breathe. Parts of your respiratory system include your:

• Nose and nasal cavity.
• Mouth and oral cavity.
• Sinuses.
• Pharynx (throat).
• Larynx (voice box).
• Trachea (windpipe).
• Bronchi (large airways).
• Lungs.
• Diaphragm.

What’s your upper respiratory tract?

Your upper respiratory tract brings air into your body and helps move it toward your lungs. It adds moisture to the air you breathe in. Your respiratory tract starts with your nose and mouth, where you pull air into your body. Other parts of your upper respiratory tract include your nasal cavity, sinuses (hollow areas in your cheeks and forehead) and larynx.

What’s your lower respiratory tract?

Your lower respiratory tract consists of your trachea, bronchi and lungs. Your trachea, bronchi and bronchioles (small airways) make up your tracheobronchial (pronounced “tray-key-oh-BRON-key-uhl”) tree, a series of increasingly smaller tubes that transport air from your upper respiratory tract to small air sacs in your lungs (alveoli). (It looks a bit like an upside-down tree.)

How does your respiratory system work?

Your cells need oxygen to create energy. Creating energy releases carbon dioxide as a waste product, which can harm your body if too much builds up. The main job of your respiratory system is to bring oxygen into your lungs and move carbon dioxide out of them (gas exchange). It works closely with your circulatory system — your heart, blood and blood vessels — to do this.

Think of the oxygen in the air as passengers on millions of planes flying into your lungs every time you breathe in. Your diaphragm pulls down, creating more space in your chest, which pulls air (and its tiny oxygen cargo) into your lungs. The air travels through your mouth or nose and down your trachea, bronchi and bronchioles, like airport runways. Then the passengers arrive at the airport gates, your alveoli.

There, the oxygen moves through the membranes surrounding your lungs into small blood vessels (capillaries). You can imagine it like the oxygen passengers getting picked up by a taxi at the airport. Finally, the taxi travels out to your tissues, dropping off oxygen to give your cells energy.

How your respiratory system gets rid of carbon dioxide

When cells use energy, they produce carbon dioxide. When the oxygen gets out of the taxi in your tissues, carbon dioxide molecules hop in. From there, they travel through your bloodstream and to the airport gates in your lungs. They fly out of your lungs when your diaphragm moves back upwards, making your chest cavity smaller and causing you to push the air out the way it came.

Other functions

While you’re breathing in and out, your respiratory system also protects your body from dry air and potentially harmful particles. When you inhale, your sinuses help regulate the temperature and humidity of the air.

As air moves through your nostrils and down your airways, tiny hairs (cilia) filter out dust, germs and other irritants to keep them from getting into your airways and lungs. When irritants or germs do find their way in, your respiratory system traps them in mucus. Then cilia in your airways move in a wavelike motion to push the mucus out of your body when you cough or sneeze.

What conditions affect your respiratory system?

Many conditions can affect the organs and tissues that make up your respiratory system. Irritants and germs you breathe in from the air — including viruses, bacteria and fungi that cause infections — can cause some of these conditions. Others are the result of damage or genetic diseases.

Conditions that can affect your respiratory system include:

• Allergic rhinitis. Allergic reactions to tree pollen, pet dander, dust and other allergens can affect your airways and nasal passages.
• Chronic airway conditions. These include asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis.
• Upper and lower respiratory infections. Common respiratory infections include the flu (influenza) or common colds.
• Inflammation. Infections can lead to swelling in your large airways (bronchitis), alveoli (pneumonia), sinuses (sinusitis) or other parts of your respiratory system.
• Interstitial lung disease (ILD). Pulmonary fibrosis and other ILDs can cause permanent scarring in your lungs.
• Blockages. This could be a foreign object, a benign growth or a cancerous tumor.
• Acid-base imbalances. Respiratory alkalosis and respiratory acidosis happen when you’re exhaling too much or too little carbon dioxide, changing the acid-base balance in your blood.
• Too little oxygen or too much carbon dioxide in your blood or tissues. While they may seem like blood conditions, hypoxemia, hypoxia and hypercapnia can all be signs that something’s wrong with your respiratory system.

What are the signs or symptoms of conditions that affect your respiratory system?

Conditions that affect your respiratory system might cause:

• Shortness of breath (dyspnea).
• Runny or stuffy nose.
• Blue skin, lips or nails (cyanosis).

What tests do healthcare providers use to diagnose respiratory conditions?

Healthcare providers use many tests and procedures to check the health of your respiratory system. Depending on your symptoms, these might include:

• Pulse oximetry (pulse ox). This is a simple, routine test that uses a device on your finger to measure your blood oxygen level.
• Pulmonary function tests.
• Chest X-rays.
• Arterial blood gas.

What are common treatments for respiratory conditions?

The treatments you’ll receive depend on what respiratory condition you have and how severe it is. Some treatments might include:

• Inhaled corticosteroids or bronchodilators. If you have asthma, COPD or other conditions that narrow your airways, you might use an inhaler regularly.
• Antiviral, antibiotic or antifungal medications for infections.
• Antihistamines.
• Leukotriene modifiers.
• Pulmonary rehabilitation.
• Surgery for tumors or other blockages.
• Lung transplant.

How can I keep my respiratory system healthy?

To keep your respiratory system healthy:

• Don’t smoke or vape. Smoking causes many lung and airway diseases or makes them worse. Vaping liquids often have many of the same ingredients as cigarettes.
• Avoid pollutants that can damage your airways. This includes secondhand smoke, chemicals and radon (a radioactive gas that can cause cancer). Wear a mask if you’re exposed to fumes, dust or other types of pollutants during your job or hobbies.
• Stay hydrated. Drinking plenty of water keeps the mucus in your lungs thin and easier to clear out.
• Exercise regularly. Exercise keeps the muscles in your lungs strong and makes breathing easier.
• Prevent infections. Washing your hands often and getting vaccinated against respiratory illnesses can help prevent you from getting sick.

When should I call a healthcare provider?

Contact your provider if you have a long-lasting or worsening cough, shortness of breath or other symptoms of a respiratory condition. See your provider for regular checkups. Early diagnosis of respiratory issues can help prevent them from becoming severe.

A note from Cleveland Clinic

Breathe in. Breathe out. Your breathing can calm and center you. It helps you smell and taste and even allows you to sing along to your favorite song. Most importantly, your respiratory system brings in oxygen to give your cells energy and gets rid of carbon dioxide so it doesn’t build up in your body. If something’s amiss with your respiratory system, you might cough, wheeze or get out of breath quickly. Talk to your healthcare provider about any concerning symptoms. They can help you breathe easier.