Cambridge O Level Biology · Syllabus 5090 · Human Gas Exchange
Bronchiole
What is Bronchiole?
One of the fine tubes into which each bronchus divides repeatedly inside a lung. Bronchioles have much narrower diameters than the bronchi and their walls contain no cartilage rings. They form a branching network that distributes air throughout the lung tissue and delivers it to the clusters of alveoli at their ends. No gas exchange takes place across the wall of a bronchiole; like the trachea and bronchi it is part of the conducting airway, whose job is to carry air, warm it, moisten it and trap particles in mucus before the air reaches the exchange surface.
This definition is part of the Human Gas Exchange chapter in Cambridge O Level Biology.
Questions students ask about Bronchiole
Where in the body does gas exchange happen?
At the alveoli, the microscopic air sacs at the ends of the finest bronchioles in the lungs. Nowhere else in the gas-exchange system does any gas move between the air and the blood. The nose, larynx, trachea, bronchi and bronchioles carry air but exchange none of it.