Topics:
Animal Physiology, Animal Refresher
Chemical Identity of Pulmonary Surfactant
Pulmonary surfactant is:
- Dipalmitoylphosphatidylcholine (DPPC) — Correct Answer
- Sodium lauryl sulfate (SLS)
- Cyclophosphamide
- Dipalmitoyl lecithin only
Explanation:
Correct Answer: Dipalmitoylphosphatidylcholine (DPPC)
Pulmonary surfactant is Dipalmitoylphosphatidylcholine (DPPC), also known as Dipalmitoyl lecithin. Both names are correct for the same molecule.
About Pulmonary Surfactant
- Function: Surface tension-lowering agent; prevents collapse (atelectasis) of alveolar sacs during expiration.
- Produced by: Type II pneumocytes (type II alveolar cells) in mammals.
- In birds, surfactant-secreting cells are called granular cells (not type II pneumocytes).
Neonatal Respiratory Distress Syndrome (NRDS)
- Premature neonates lack sufficient surfactant → alveoli collapse → respiratory distress.
- Treatment: exogenous surfactant administration.
- Ratio of lecithin to sphingomyelin (L/S ratio) in amniotic fluid > 2 indicates fetal lung maturity.
Why Sodium Lauryl Sulfate is Wrong
SLS is a detergent/chemical defaunation agent used to remove protozoa from the rumen ecosystem (chemical defaunation) — completely unrelated to pulmonary surfactant.
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
