A surfactant acts as an emulsifier or detergent.
Surfactant is a term that derives from surfactant , an English word. This, in turn, is an acronym formed from the expression surface active agent (which can be translated as “surface active agent” ).
A surfactant is an element that acts as a detergent , emulsifier or humectant and that reduces the surface tension that exists in a fluid . In general, these are substances that influence the contact zone created between two phases.
It should be noted that surface tension refers to the level of energy needed for a liquid to increase its surface area per unit area. This means that there is a resistance in the liquid to increase the surface area.
Composition of a surfactant
Surfactants, which are also called surfactants or surfactants , are composed of hydrophobic parts (which reject water) and hydrophilic parts (which are soluble in water). In this way, when the surfactant binds to water , the molecules of the first group remain at the surface level, while the hydrophilic ones submerge. This causes bubbles to form, for example.
Due to these characteristics, detergents are used to wash certain objects. These surfactants, when they come into contact with water, trigger various phenomena that allow foam to be generated and drag away grease and other substances adhered to what is to be washed.
Pulmonary surfactant contributes to reducing alveolar surface tension.
A substance present in the lungs
Finally, a substance found in the alveoli of the lungs and that helps minimize alveolar surface tension is known as pulmonary surfactant . This surfactant is made up of proteins , neutral lipids , phospholipids and other substances.
Of its components, 80% are phospholipids , and in this group dipalmitoylphosphatidylcholine (known simply as DPPC or surfactant factor ) predominates, which is produced by type II pneumocyte cells, which are present in the alveolar epithelium and are cube-shaped. . Although DPPC is capable of reducing alveolar surface tension on its own, the rest of the aforementioned components also fulfill necessary functions, such as increasing immunity to pathogens that enter through inhalation.
As explained in previous paragraphs, pulmonary surfactant is also a surfactant, meaning that when it comes into contact with water it undergoes a change in its surface tension . When pulmonary surfactant is secreted, it becomes a thin film that comes into contact with air and spreads over the entire alveolar epithelium.
In addition to reducing the tension that occurs in the alveoli throughout the respiratory process (more specifically during exhalation), pulmonary surfactant also offers an immunological action against viruses and bacteria that enter along with the air, to prevent them from going beyond the capillaries and begin to invade the bloodstream; If it were not for this substance, both the lungs and other organs would be highly exposed to various infectious diseases.
Several hormones and other substances in our body, such as prolactin , thyroxine, glucocorticoids and estradiol, are responsible for stimulating the generation of pulmonary surfactant. On the other hand, there are also others that perform the opposite action , that is, they inhibit its production, and among them we find androgens and insulin.
The function of the lungs depends largely on the amount of surfactant it has, as well as its quality, since deficient levels or certain defects in its composition can lead to considerable alterations, such as hyaline membrane disease , which affects to premature newborn babies, making it considerably difficult for them to breathe and putting their lives at risk.