The bronchi are the two large tubes that carry air from your windpipe to your lungs. You have a left and right main bronchus in each lung. After the main bronchi, these tubes branch out into segments that look like tree branches. Many respiratory conditions, such as asthma or bronchitis, can affect your bronchi.
Your bronchi (BRAWN-kai) are the large tubes that connect to your trachea (windpipe) and direct the air you breathe to your right and left lungs. They are in your chest. Bronchi is the plural form of bronchus. The left bronchus carries air to your left lung. The right bronchus carries air to your right lung. Your bronchi are an essential part of your respiratory system. As you breathe and your lungs expand, your bronchi distribute the air within your lung.
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The bronchi are part of the tracheobronchial tree. The tracheobronchial tree is where air passes to your lungs and exchanges gases (oxygen and carbon dioxide).
The tracheobronchial tree includes your:
Your bronchi carry air to and from your lungs. The bronchi also help moisturize the air you breathe and screen out foreign particles.
Your airways are lined with cells that create mucus. The mucus keeps your airways moist. It also traps bacteria, viruses, fungi and other particles to protect your lungs and prevent infection.
The bronchi are lined with cilia, tiny hairlike structures. The cilia help move mucus (phlegm) and particles out of your lungs. When you cough or swallow, the particles trapped in the mucus move out of your body or into your digestive tract, where your body can dispose of them.
Your bronchi work with your respiratory system to help you breathe. When you breathe:
When you breathe in, oxygen moves to your bloodstream. When you breathe out, you expel carbon dioxide. This process is known as gas exchange.
Gas exchange takes place in the alveoli in your lungs. You have about 480 million alveoli to do this vital job. Your bronchi are not involved in gas exchange — they only supply air to the alveoli.
Your bronchi have two main (or primary, or first) parts:
Your right and left main bronchi are the widest portions of your bronchi. Then your bronchi divide into branches that get smaller and smaller starting with:
Your tracheobronchial tree looks like an upside-down tree with the trachea as the trunk and the bronchi representing the branches. The tubes of the right and left main bronchi divide into smaller segments as they move deeper into your lungs. Similarly, tree branches divide and get smaller and smaller, before ending in the leaves.
You have bronchi throughout both lungs:
Several conditions can affect your bronchi, including:
Depending on your symptoms, your healthcare provider may use pulmonary function tests to check the health of your bronchi and lungs. Other common tests include:
Certain respiratory conditions are among the most common illnesses worldwide. Approximately:
To keep your bronchi, lungs and entire respiratory system healthy, you can:
You should call 911 or go to your nearest emergency room if you experience any signs of respiratory distress. Signs of respiratory distress include:
A note from Cleveland Clinic
The bronchi are the passageways that connect your windpipe to your lungs. You have two main bronchi in your right and left lungs that divide and branch off into smaller segments, like tree branches. At the end of your bronchi, the alveoli exchange oxygen and carbon dioxide. Many infections and conditions can affect the bronchi. But you can keep your bronchi and lungs healthier by avoiding smoke, chemicals, infections and air pollution.
Last reviewed by a Cleveland Clinic medical professional on 06/21/2021.
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