The alveolar cell that secretes pulmonary surfactant is the?
Type I (Squamous Alveolar)
What is pulmonary surfactant?
Pulmonary surfactant is a surface-active lipoprotein complex (phospholipoprotein) formed by type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions
What secretes the lung surfactant?
Surfactant production in humans begins in Type II cells during the alveolar sac stage of lung development. Lamellar Bodies appear in the cytoplasm at about 20 weeks gestation. These lamellar bodies are secreted by exocytosis into the surface water layer lining the alveolar airspace, where the surfactant forms a meshwork of tubular myelin.
Is alpha-1-antitrypsin related to surfactants in the lung? If yes, how?
I don't think it has anything to do with surfactant, although I must confess a certain ignorance. As an RT of 32+ years I only treated people with this disease a few times in my career. It basically is a form of genetic emphysema and it is treated in the same way as emphysema of the normal kind. However, I should qualify my answer by saying that if not treated promptly and properly when symptoms such as pneumonia occur then it may indeed AFFECT the surfactant performance, as a result of the pneumonia. ARDS (Adult Respiratory Distress Syndrome) can cause changes in surfactant quality, but this is a result of pneumonia rather than the deficiency. Good luck and God Bless.
Type II alveolar cells?
a. secrete a chemical known as surfactant. b. all of the above c. are phagocytic. d. none of the above e. allow rapid diffusion of gases through their thin membranes.
What are alveolar cells?
Alveolar cells is also called pneumocytes are cells lining the alveoli of the lungs. Two types of alveolar cell exist are type I alveolar cells and type II alveolar cells.Type I alveolar cells:They are squamous and cover approximately 90–95% of the alveolar surface. Type I cells are involved in the process of gas exchange between the alveoli and blood.Type II alveolar cells :They are cover a small fraction of the alveolar surface area. Their function is of major importance in the secretion of pulmonary surfactant which decreases the surface tension within the alveoli.
Is an alveolar wall unicellular or multicellular?
Alveolar Epithelial surface is made up of Cells namely pneumocytes, Type I and II.Type I pneumocytes comprises 95–96% of the alveolar surface area. These cells are extremely thin of diameter 50µm overall extension is 2300 µm with few organelles; this helps in minimizing distance of diffusion between the alveolar air sac and pulmonary capillary blood.Type II Pneumocytes comprises of only 4% of the alveolar Surface area yet 60 % of alveolar surface area is covered with this and 10-15% of all lung cellsMain function of type II cells includesSecretion and synthesis of surfactantsMetabolism of xenobioticsTransepithelial movement of waterRegeneration of alveolar epithelium following a lung injuryReferences:Type I pneumocyteThe alveolar type II epithelial cell: a multifunctional pneumocyte.V. Castranova, J. Rabovsky, J. H. Tucker, P. R. MilesToxicol Appl Pharmacol. 1988 May; 93(3): 472–483.
Elastic tissue in the alveoli?
I think what they're saying is that it expands-recoils, expands-recoil, and on and on. What makes for this ability is collagen and elastic fibers. The alveoli stretch (expand) when they fill and spring back (recoil) to expel the carbon dioxide. And each alveolus is enmeshed and surrounded by capillaries like being covered with a net that stretches with it. These capillaries are even fenestrated (have holes in them) to allow for quickened gas exchange. There are three major alveolar cell types in the alveolar wall (pneumocytes): Type I (Squamous Alveolar) cells that form the structure of an alveolar wall Type II (Great Alveolar) cells that secrete pulmonary surfactant to lower the surface tension of water and allows the membrane to separate, thereby increasing the capability to exchange gases. Surfactant is continuously released by exocytosis. It forms an underlying aqueous protein-containing hypophase and an overlying phospholipid film composed primarily of dipalmitoyl phosphatidylcholine. Macrophages that destroy foreign material, such as bacteria.
What is the function of the surfactant in mammalian lungs?
Pneumonic surfactant is a blend of lipids and proteins which is emitted into the alveolar space by epithelial sort II cells. The primary capacity of surfactant is to bring down the surface pressure at the air/fluid interface inside the alveoli of the lung.