Simple cuboidal epitheliumOne layer of cube-shaped cells, many with cilia. A bronchus has a taller lining.
Club cellA secretory cell without cilia. It sits among the ciliated cells of a bronchiole.
Smooth muscleA ring of smooth muscle around the bronchiole. No cartilage lies outside it.
AlveoliThin-walled air sacs all around the bronchiole. Gas exchange takes place in them.
Bronchus 7
Pseudostratified epitheliumThe tall ciliated lining of a bronchus. Goblet cells are scattered through it.
Goblet cellA mucus-secreting cell in the lining. Cilia sweep the mucus and its dust up the airway.
Cartilage plateAn irregular plate of hyaline cartilage. Plates like it hold a bronchus open; a bronchiole has none.
Mucous glandsSmall glands in the wall of a bronchus. They secrete mucus.
Smooth muscle (bronchus)Bundles of smooth muscle around the bronchus. They lie between the lining and the cartilage.
LumenThe open space of the airway. Air passes through it.
Pulmonary artery branchA branch of the pulmonary artery. Its branches run beside the airways.
How this list was compiled: Every name read on 2026-10-03 and kept only where two independent sources give it. (1) Henry Gray, Anatomy of the Human Body (1918, public domain), The Lungs, structure, https://www.theodora.com/anatomy/the_lungs.html : the plates of hyaline cartilage, the bronchial muscle, the ciliated lining and the mucous glands of a bronchus; bronchioles with no cartilage and cubical ciliated cells; the branches of the pulmonary artery that accompany the bronchial tubes. (2) Wikipedia, text only: Bronchus, Bronchiole, Club cell and Respiratory epithelium, https://en.wikipedia.org/wiki/Bronchus and https://en.wikipedia.org/wiki/Bronchiole . (3) Southern Illinois University School of Medicine, Histology Study Guide, Respiratory System, https://histology.siu.edu/crr/rsguide.htm : pseudostratified ciliated epithelium with goblet cells, cartilage in bronchi and none in bronchioles, simple cuboidal epithelium and club cells in bronchioles, smooth muscle, small mucous glands, alveoli. (4) Rokicki and others, the review of club cells that the university guide cites, Kardiochirurgia i Torakochirurgia Polska 13:26 (2016), open access, https://europepmc.org/article/PMC/PMC4860431 : club cells bulge into the lumen of the bronchiole, have no cilia and secrete substances that protect the small airways. The drawing is our own. Licence: own work
The drawing: Drawn for this site on 2026-10-03 from plain geometry. Own original drawing; nothing traced or copied. Not to scale. Licence: own work
How it works
The first view is a bronchiole cut across, with alveoli around it. The second is bronchi histology labeled the same way: one bronchus with its cartilage plates, glands and artery. Both are drawings, not photos.
Read the full guide
The bronchiole
Start at the open center. One layer of cuboidal cells lines it; the bulging cells without cilia are club cells. Outside the lining is a ring of smooth muscle, and around that the alveoli. There is no cartilage.
The bronchus
The lining is taller here: pseudostratified ciliated epithelium with oval goblet cells. Then come bundles of smooth muscle and an outer coat with mucous glands and plates of hyaline cartilage. The round vessel beside it is a branch of the pulmonary artery.
Cartilage means bronchus. No cartilage means bronchiole.
Questions and answers
How do you tell a bronchus from a bronchiole on a slide?
Look for cartilage. A bronchus has plates of hyaline cartilage and glands in its wall, and a tall pseudostratified ciliated epithelium with goblet cells. A bronchiole has no cartilage, and its lining is a single layer of cuboidal cells.
What type of epithelium lines a bronchiole?
Simple cuboidal epithelium. Many of its cells are ciliated, and club cells without cilia sit among them. The lining gets lower as the bronchioles get smaller.
What are club cells?
Secretory cells without cilia in the lining of the bronchioles. Their secretions help protect the lining.
What surrounds a bronchiole?
A ring of smooth muscle, then the alveoli of the lung. Branches of the pulmonary artery run beside the airways.