What are bronchioles?

It is called the bronchioles. Gray's Anatomy (1918) describes it as the smallest air-conducting tubes of the lung.

What it is

  • The smallest air-conducting tubes of the lung.
  • Less than 1 mm across.
  • Their walls contain smooth muscle but no cartilage.

Where it is

  • Inside the lungs, beyond the smallest bronchi.
  • End in the terminal bronchioles, which lead to the alveoli.
  • Distributed throughout every part of the lung.

Source:

Last verified: 2026-07-18

  • Best Anatomy Answers is an educational reference about human anatomy. It is not medical advice — for any health concern, talk to a licensed medical professional.

View as .md