Respiratory Epithelium - Anatomy & Physiology

Introduction

Respiratory epithelium is a type of epithelium which lines both the upper and lower respiratory tracts.

It consists of multiple layers of cylindrical epithelium, along with cilia and goblet cells.

Function

Air Modification

Upon entry to the respiratory system, air is modified to protect the system:

• Particles trapped and removed by the Mucociliary Escalator.
• Air is humidified by the evaporation from mucus and secretions from the epithelium.
• Air ia warmed due to the close proximity to the capillary network underlying the respiratory epithelium.

Mucociliary escalator

The many cilia present on the surface of the cells of respiratory epithelium, along with the mucus producing goblet cells, are the functional units for the Mucociliary escalator:

• Cilia on the respiratory epithelium beat in a co-ordinated manner
  • Cilia beat in a caudal direction in nasal cavity
  • Cilia beat in a cranial direction in trachea and lower airways
  • Mucus is swallowed when it reaches the nasopharynx.
  • Constant movement reduces chances that pathogens can adhere to the respiratory epithelium.