[RS]Q.7 What is surfactant give its composition and important

Ans.

Surfactant:

It is a surface active agent in water of lung alveoli which greatly reduces the surface tension of the fluid lining the lung alveoli, composed of several phospholipid, proteins and ions and secreted by special surfactant secreting epithelial cells called type-II alveolar cells.

Composition:

·  Phospholipid – dipalmitoyl phosphatidycholine.

·  Surfactant apoproteins

·  Calcium ions

Importance:

Ø                 Surfactant decrease the surface tension of the fluid lining the alveoli          thus prevents the lungs collapse.

Ø                 It helps in the expansion of lungs of a new born babies.

Ø                 It stabilizes the size of alveoli.

Ø                 It prevents the accumulation of edema fluid in alveoli.