American Academy of Professional Coders (AAPC) Practice Exam

What layer lies beneath the epithelium in a mucous membrane?

1. Basal Layer

2. Lamina Propria

3. Submucosa

4. Epithelial Layer

The correct answer is: Lamina Propria

The correct answer is the lamina propria. This layer is crucial in the structure of mucous membranes, situated just beneath the epithelium. It consists of a thin layer of connective tissue that provides support and nourishment to the epithelial cells above. The lamina propria contains blood vessels, lymphatics, and immune cells, playing a vital role in the overall function of the mucous membrane, including its ability to act as a barrier and facilitate the secretion of mucus. The basal layer, although part of the epithelium, specifically refers to the deepest layer of epithelial cells that contributes to regeneration and does not lie beneath the epithelial layer as a distinct structure. The submucosa is located beneath the lamina propria, containing more complex structures, including larger blood vessels and nerves. It is a separate layer that often supports the mucous membrane but does not directly sit beneath the epithelium itself. Finally, the epithelial layer is the outermost layer of the mucous membrane, covering it and does not lie beneath itself. Understanding these structural components is essential for comprehending the organization and function of mucosal tissues.