What does bronchiole mean?
A bronchiole is any of the thousands of tiny air tubes that make up the deepest branches of the lung's airway system. After the windpipe divides into two main bronchi, those bronchi split repeatedly into ever-smaller passages, and once they become too narrow to be supported by cartilage, they are called bronchioles. These delicate tubes, typically less than a millimetre across, regulate airflow through bands of smooth muscle and deliver air to the alveoli, the microscopic sacs where oxygen passes into the blood. Because of their small size, bronchioles are vulnerable to narrowing or inflammation in conditions such as asthma and bronchiolitis, which is why the word appears frequently in medical contexts. Derived from the Latin diminutive of "bronchus," the term literally means "little windpipe." Though technical, it is essential vocabulary for understanding respiratory anatomy.
nounAny of the many fine branching air passages in the lungs that lead from the bronchi into the pulmonary lobules and ultimately to the alveoli, where gas exchange occurs.
- A minute branch of the bronchial tree conveying air from the bronchi to the alveoli of the lung.
"Inflammation of the smallest bronchioles can make breathing dangerously difficult for infants."
"Cigarette smoke scarred the delicate walls of her terminal bronchioles."
"Under the microscope, each bronchiole appeared as a thin tube ringed with smooth muscle."
Standard regular plural; used when referring collectively to the many fine airways of the lungs.
"Viral infections can cause swelling in the bronchioles of young children."
Your trachea splits just twice before reaching your lungs, but it takes more than twenty further generations of branching before it narrows into bronchioles thinner than a strand of spaghetti.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bronchiole
The word bronchiole comes from the Latin diminutive form of "bronchus," itself borrowed from Greek "bronchos" (βρόγχος), meaning windpipe or throat. The diminutive suffix conveys its literal sense of a "little bronchus," reflecting how anatomists named these finer airway branches as they mapped the branching structure of the lungs. It shares this Greek root with related medical terms such as "bronchial" and "bronchitis," and entered scientific English as anatomy developed its modern Latinate vocabulary.
Related word forms
How bronchiole is actually used
Strictly a technical term used in anatomy, medicine, and physiology; rarely encountered in casual conversation. In clinical usage it is often modified by qualifiers such as "terminal" or "respiratory" to indicate how far along the airway the bronchiole sits.
Easily confused with bronchiole
A bronchus is one of the two large main branches of the windpipe entering the lungs, while a bronchiole is one of the much finer passages those bronchi divide into.
An alveolus is the tiny air sac at the very end of the airway where oxygen is exchanged for carbon dioxide; bronchioles are the passages that deliver air to those sacs.