THE MOST ABUNDANT COMPONENT OF SURFACTANT IS

• A. SP-A
• B. PG
• C. Lecithin (phosphatidylcholine) ✓
• D. Sphingomyelin

The most abundant component of surfactant is Lecithin (phosphatidylcholine). Surfactant is a complex mixture of lipids and proteins that lines the alveoli in the lungs and plays a crucial role in reducing surface tension, preventing alveolar collapse, and maintaining lung compliance. Phosphatidylcholine, also known as lecithin, is the primary lipid component of pulmonary surfactant, making up approximately 80% of the total phospholipids present in surfactant. It is essential for reducing surface tension at the air-liquid interface within the alveoli, thereby preventing lung collapse during expiration and promoting efficient gas exchange.

In other words, Surfactant is a complex mixture of lipids and proteins that lines the alveoli in the lungs. It plays a crucial role in reducing surface tension, preventing alveolar collapse, and facilitating gas exchange. The main components of surfactant include phospholipids, neutral lipids, and surfactant proteins.

Phospholipids in Surfactant

Phospholipids are the major lipid component of surfactant. Among phospholipids, lecithin (phosphatidylcholine) is the most abundant type found in surfactant. Lecithin accounts for approximately 80% of the total phospholipid content in surfactant.

Other Components of Surfactant

In addition to phospholipids, surfactant also contains other components such as:

• SP-A (Surfactant Protein A): SP-A is one of the surfactant proteins that play a role in immune defense and regulation of surfactant metabolism. While important, SP-A is not the most abundant component of surfactant.
• PG (Phosphatidylglycerol): PG is another type of phospholipid present in surfactant but is not as abundant as lecithin.
• Sphingomyelin: Sphingomyelin is a minor component of surfactant and is not as prevalent as lecithin.