Write a note on surfactants and Why do premature babies have low surfactant?

Explanation

The thin squamous epithelial cells of the alveoli are composed of Type I and Type II cells.
2. Type I cells are very thin so that gases can diffuse rapidly through them.
3. Type II cells are thicker, synthesize and secrete a substance called Surfactant.
4. Surfa ctan ts are the thin non-cellular films made of protein and phospholipids covering the alveolar membrane.
5. The surfactant lowers the surface tension in the alveoli and prevents the lungs from collapsing.
6. It also prevents pulmonary oedema.
7. Premature Babies have low levels of surfactant in the alveoli may develop the new born res pira tory distress syndrome (NRDS) because the synthesis of surfactants begins only after the 25th week of gestation.