So what the pulmonary surfactant does is it basically decreases the surface tension of the fluid and it makes it much easier for us to actually breathe in and apply a smaller pressure to inflate those balloon like structures, our alveoli. So pulmonary surfactant is a substance that resembles our detergent because it consists of about 90% of phospholipids and it also contains about 10% protein. So that means it contains polar hydrophilic and nonpolar hydrophobic regions. So these tiny molecules shown here are basically our surfactant molecules. So we have the non polar hydrophobic tail and the polar hydrophilic head. So in the same way that we discussed here, the head of the surfactant, the head of the surfactant basically interacts with the surface of our fluid, but the tail points away towards our air found within this cavity.