Answer:
Surfactant in the lungs helps to increase expansion of the lungs
Step-by-step explanation:
Pulmonary surfactant is a substance composed mainly of proteins and lipids, which acts as a surface active agent, preventing the pulmonary alveoli from collapsing or closing.
The pulmonary alveoli are responsible for carrying out the gaseous exchange, passing oxygen into the blood and receiving the carbon dioxide that they must eliminate. Pulmonary surfactant —secreted by type II pneumocytes— decreases the surface tension of the alveolar liquid, preventing its closure and facilitating its expansion.
The other options are not correct because:
a. Expiration is one of the components of the respiratory cycle, and is not related to the surfactant.
b. Rales (crackles) are abnormal breathing sounds, due to the presence of fluid in the alveoli.
d. Orthopnea is the sitting position that a person adopts when he or she has severe breathing difficulty, preventing him or her from lying down.
e. Exhalation = expiration.