True regarding surfactants - (PGI Dec 09)
|A||Secreted by type II pneumocyte|
|B||Contained in osmiophilic lamellar body|
|C||Deficiency results in hyaline membrane disease|
|D||In broncho-alveolar carcinoma its secretion is increased|
[Ref" Robbins 8t1I/e p. 456;]
a. Pulmonary surfactants are surface-active lipoprotein complex (phospholipoprotein) formed by type II alveolar cells (type II pneumocytes).
b. Surfactants are contained in osmiophilic lamellar body of type II pneumocytes
c. The proteins and lipids components of surfactant have both a hydrophobic and a hydrophilic region.
d. By this mechanism surfactant has two functions:
i. To increase pulmonary compliance
ii. To prevent atelactasis (collapse of lung) at the end of expiration.
• Deficiency of surfactant results in hyaline membrane disease (HMD) of newborn in premature delivery.