Advanced Dental Admission Test (ADAT)

Which of the following statements about Clara cells is true?

1. They produce mucous.

2. They are involved in gas exchange.

3. They produce surfactant.

4. They are responsible for sensation.

The correct answer is: They produce surfactant.

Clara cells, also known as Club cells, are specialized epithelial cells found in the lungs, particularly in the bronchioles. One of their primary functions is the production of surfactant, a substance that decreases surface tension within the alveoli. This property is crucial for maintaining the structural integrity of the lungs and preventing alveolar collapse during exhalation. Producing surfactant helps improve gas exchange efficiency by stabilizing the alveolar surface. While Clara cells play a significant role in respiratory health and function, they are not primarily involved in mucous production, gas exchange, or sensation. Mucous is mainly produced by goblet cells, gas exchange occurs in the alveoli with the assistance of alveolar type I and II cells, and sensation in the respiratory tract is typically mediated by different sensory nerve cells. Therefore, the statement regarding their production of surfactant accurately captures one of their key functional roles in the respiratory system.