Question

Surfactant is:

A) produced by the mucous cells of the left and right mainstem bronchi.
B) quickly destroyed in patients who have a severe upper airway obstruction.
C) a phospholipid compound that decreases surface tension on the alveolar walls.
D) a lubricating substance that increases alveolar surface tension during breathing.

Answer 1

Surfactant is a phospholipid compound that decreases surface tension in the alveoli, facilitating easier breathing and preventing collapse of the alveoli.

Step-by-step explanation:

Surfactant is a detergent-like substance that plays a crucial role in the respiratory system by reducing the surface tension within the alveoli, the small air sacs in the lungs. The substance is a complex mixture of phospholipids and lipoproteins. During breathing, the surfactant reduces the effort required to inflate the alveoli and helps to prevent their collapse. Without sufficient surfactant, as seen in premature infants, the condition known as respiratory distress syndrome can occur, making breathing laborious due to the increased surface tension and tendency of the alveoli to collapse.

To directly address the student's question, option C) is correct: surfactant is a phospholipid compound that decreases surface tension on the alveolar walls.