The alveoli contain specialized cells that secrete a phospho lipoprot...
Thin layer of water on the inner surface of alveoli serves to contract the alveoli and makes them behave like unfilled balloons that resist inflation. This would mean tremendous effort to inhale and expand the alveoli and therefore to overcome this cells of the alveoli secrete pulmonary surfactant to decrease the surface tension of water lining the alveoli.
The alveoli contain specialized cells that secrete a phospho lipoprot...
Function of Pulmonary Surfactant:
The function of pulmonary surfactant is to decrease the surface tension of the alveoli, making it easier to expand them. This is the correct answer.
Explanation:
Pulmonary Surfactant:
- Pulmonary surfactant is a phospholipid-protein complex secreted by specialized cells in the alveoli called type II pneumocytes.
- It is composed of phospholipids (mainly dipalmitoylphosphatidylcholine), proteins, and small amounts of other lipids.
- This surfactant lines the surface of the alveoli and reduces surface tension.
Surface Tension and Alveolar Expansion:
- Surface tension is the force that acts at the surface of a liquid and tends to minimize the surface area.
- In the alveoli, the presence of water molecules creates surface tension at the air-liquid interface.
- Surface tension tends to collapse the alveoli and make it difficult for them to expand during inhalation.
Role of Pulmonary Surfactant:
- Pulmonary surfactant plays a crucial role in reducing the surface tension of the alveoli.
- It does this by disrupting the cohesive forces between water molecules at the air-liquid interface, thereby reducing surface tension.
- By reducing surface tension, surfactant prevents the alveoli from collapsing and makes it easier to expand them during inhalation.
- This allows for efficient gas exchange in the lungs, as the alveoli can readily expand and accommodate air.
Significance of Pulmonary Surfactant:
- The presence of pulmonary surfactant is essential for the proper functioning of the respiratory system.
- In premature infants, the production of surfactant may be insufficient, leading to a condition called respiratory distress syndrome (RDS).
- RDS is characterized by difficulty in breathing and inadequate gas exchange due to the collapse of alveoli.
- Treatment with exogenous surfactant can alleviate the symptoms of RDS by restoring the surface tension-lowering properties of surfactant.
Conclusion:
In summary, the function of pulmonary surfactant is to decrease the surface tension of the alveoli, making it easier to expand them. This allows for efficient gas exchange in the lungs and prevents alveolar collapse.
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