What are the cells that produce surfactant called?
What are the cells that produce surfactant called?
The pulmonary surfactant is produced by the alveolar type-II (AT-II) cells of the lungs. It is essential for efficient exchange of gases and for maintaining the structural integrity of alveoli. Surfactant is a secretory product, composed of lipids and proteins.
What are AT2 cells?
AT2 cells are smaller, cuboidal cells that are best known for their functions in synthesizing and secreting pulmonary surfactant. In addition, AT2 cells serve as alveolar stem cells and can differentiate into AT1 cells during alveolar homeostasis and post injury repair (1⇓–3).
What is responsible for the secretion of surfactant?
Abstract. Pulmonary surfactant is a mixture of lipids and proteins which is secreted by the epithelial type II cells into the alveolar space. Its main function is to reduce the surface tension at the air/liquid interface in the lung.
What is the role of surfactant in the lung?
Pulmonary surfactant is essential for life as it lines the alveoli to lower surface tension, thereby preventing atelectasis during breathing. Surfactant is enriched with a relatively unique phospholipid, termed dipalmitoylphosphatidylcholine, and four surfactant-associated proteins, SP-A, SP-B, SP-C, and SP-D.
Why surfactants are used?
The main purpose of the surfactants is to decrease the surface and interfacial tension and stabilize the interface. Without surfactants washing laundry would be difficult and many of the food products like mayonnaise and ice cream would not exist.
What are the two types of alveoli?
The alveolar epithelium comprises two main cell types: the alveolar type I and alveolar type II cell. The type I cell is a complex branched cell with multiple cytoplasmic plates that are greatly attenuated and relatively devoid of organelles; these plates represent the gas exchange surface in the alveolus.
What does surfactant improve?
The surfactant reduces the surface tension of water by adsorbing at the liquid–gas interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid–liquid interface.
Why are surfactants important?
Surfactants are compounds used in an array of cleaning products for their ability to lower the surface tension of water, in essence making the molecules slipperier, so they are less likely to stick to themselves and more likely to interact with oil and grease.
Where does the secretion of surfactant take place?
Its delivery to the cell surface is preceded by surfactant component synthesis, packaging into specialized organelles termed lamellar bodies, delivery to the apical plasma membrane and fusion. Secreted surfactant undergoes reuptake, intracellular processing, and finally resecretion of recycled material.
Where is surfactant secreted in the lung cell?
Lung surfactant is synthesized in the alveolar type II cell. Its lipids and hydrophobic proteins (SP-B and SP-C) are stored in lamellar bodies and secreted by regulated exocytosis. In contrast, the hydrophilic proteins (SP-A and SP-D) appear to be secreted independently of lamellar bodies.
What kind of cells are used to measure surfactant secretion?
Surfactant secretion has been measured in several systems ranging from intact animals in vivo to isolated type II cells in culture ( Chander and Fisher, 1990, Wright and Dobbs, 1991, Mason and Voelker, 1998, Rooney, 1998 ). Isolated type II cells have been the model of choice for most studies on the regulation of surfactant secretion.
What is the function of surfactant in the immune system?
Surfactant immune function is primarily attributed to two proteins: SP-A and SP-D. These proteins can bind to sugars on the surface of pathogens and thereby opsonize them for uptake by phagocytes. It also regulates inflammatory responses and interacts with the adaptive immune response.