Conducting Epithelium

The respiratory mucosa of the conducting airways is a pseudostratified ciliated epithelium. Remember from Laboratory 2 that this epithelium is characterized by columnar cells that appear stratified because their nuclei are located on different levels, even though the cells are anchored on the same basement membrane. Cilia are visible on the apical membranes of some of these cells. The epithelium also contains goblet cells, which secrete mucous, and stem cells. The basement membrane has a glassy appearance. In the lamina propria, there are seromucous glands, as well as blood vessels and lymphatic tissue. In what direction do the cilia beat? How are ciliated and goblet cells replaced?

Answer: The cilia beat up and out of the airway to remove mucous and particles out into the throat. Basal cells act as stem cells for the airway epithelium and can differentiate into ciliated cells or goblet cells. Basal cells are small, round cells that reside on the surface of the basement membrane.