Question

A possible explanation for a smoker cough that develops when the tracheal epithelium changes from pseudo-stratified columnar to stratified squamous is that

• A. This change is accompanied by tumours that irritate the upper respiratory tract.
• B. Stratified squamous epithelium secretes more mucin than pseudostratified columnar.
• C. The stratified squamous epithelium has no cilia to remove accumulating mucus.
• D. The two events are unrelated.

Answer 1

The correct option is C The stratified squamous epithelium has no cilia to remove accumulating mucus.

The effects of tobacco smoke on the respiratory system include irritation of the trachea and larynx, reduced lung function and breathlessness due to swelling and narrowing of the lung airways and excess mucus in the lung passages.
The majority of cells found in the respiratory tract and upper airways are referred to as ciliated pseudo-stratified columnar epithelium. This means that they are partially stratified (layered) and they are shaped like columns.
The three major cell types that comprise the respiratory epithelium are ciliated cells, goblet cells (to produce mucus), and basal cells.
Smoking can cause some of these cells to either function incorrectly, or disappear entirely, leading to the ciliated pseudostratified columnar epithelium changing to a different type of epithelium (such as stratified squamous epithelium, which is better suited to a high turnover rate of cells). Hence, a smoker cough that develops when the tracheal epithelium changes from pseudo-stratified columnar to stratified squamous is that the stratified squamous epithelium has no cilia to remove accumulating mucus.

So, the correct option is 'The stratified squamous epithelium has no cilia to remove accumulating mucus'.