Basic and Clinical Sciences (BCSE) Practice Exam 2025 - Free BCSE Practice Questions and Study Guide

Respiratory epithelium is primarily composed of pseudostratified ciliated columnar epithelium, which plays a crucial role in the respiratory system's function. This type of epithelium consists of a single layer of cells that appear to be stratified due to the varying heights of the cells and the positioning of their nuclei. The cilia on the surface of these cells are essential for moving mucus and trapped particles out of the airways, thereby helping to keep the respiratory passages clear of debris and pathogens.

Additionally, the presence of goblet cells within this epithelium contributes to the secretion of mucus, which further aids in trapping dust and microorganisms, enhancing the protective mechanisms of the respiratory system. This specialized structure is well-suited for environments where airways need to efficiently filter and humidify air while also providing a barrier against pathogens.

Other types of epithelium mentioned, such as simple squamous epithelium or stratified squamous epithelium, do not possess the ciliary function or mucus-producing capabilities required in the respiratory tract. Simple squamous epithelium is more commonly found in areas requiring passive diffusion, such as the alveoli in the lungs, while stratified