This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Functional Anatomy - Respiratory System, Subject name: Physiology
Surfactant deficiency causes - 
Select and explain. 
A. Transient tachypnea of newborn, B. Respiratory distress syndrome, C. Neonatal jaundice, D. Hypertensive encephalopathy of newborn
B: Respiratory distress syndrome
Answer: B: Respiratory distress syndrome 
Explanation: Ans. is 'b' i.e., Respiratory distress sy ndrome o Infant respiratory distress syndrome is due to deficiency of surfactant. Dipalmitoylphosphatidylcholine (Dipalmitoyl-lecithin) is the major constituent of surfactant.Surfactanto Surfactant is a Soap-like substance secreted by the tvpe-II pneumocytes of the alveolar epithelium. It is a mixture of dipalmitoyl-phosphatidycholine (dipalmitoyl-lecithin), phosphatidylglvcerol, other phospholipids, neutral lipids, Surfactant proteins A, B, C and D (SP-A, SP-B, SP-C and SP-D), and carbohydrates.o Surfactant reduces the alveolar surface tension.o This has three important physiological consequences : -It reduces the collapsing tendency of lungs.It reduces the natural tendency of the smaller alveoli to collapse and empty into the larger ones. This is called alveolar stabilization.It reduces the tendency of the alveolar interstitial fluid to transudate out into the alveolar space.