Fourth-year medical students are recruited for a research study assessing their ability to interpret biopsy samples obtained during routine clinical practice. As part of the study, they are given samples of normal respiratory mucosa and asked to identify the cell types present after staining with hematoxylin and eosin. The students observe that the respiratory epithelium changes in composition as the airways continue distally from the trachea to the alveolar ducts. Which of the following features is last to disappear?

Question

Fourth-year medical students are recruited for a research study assessing their ability to interpret biopsy samples obtained during routine clinical practice.  As part of the study, they are given samples of normal respiratory mucosa and asked to identify the cell types present after staining with hematoxylin and eosin.  The students observe that the respiratory epithelium changes in composition as the airways continue distally from the trachea to the alveolar ducts.  Which of the following features is last to disappear?

Quizplus · Accepted Answer

Eductional Objective: Bronchi have a ciliated pseudostratified columnar epithelium with mucin-secreting goblet cells and submucosal mucoserous glands.  The airway epithelium gradually changes to ciliated simple cuboidal by the level of the terminal bronchioles.  Bronchioles lack glands and cartilage, and the number of goblet cells decreases distally, ending before the terminal bronchioles.  Ciliated epithelium persists up to the respiratory bronchioles.

Fourth-Year Medical Students Are Recruited for a Research Study Assessing