The mucociliary escalator covers most of the bronchi, bronchioles and nose.
It is composed of two basic parts;
1. the mucus-producing goblet cells
2. the ciliated epithelium.
The cilia are continually beating, pushing mucus up and out into the
throat. The mucociliary escalator is a major barrier against infection. Microorganisms
hoping to infect the respiratory tract are caught in the sticky mucus and moved up by the
mucociliary escalator. Note how our purple invader has been trapped in the mucus and is being pushed upward towards the throat.