What are pneumocytes?

pneumocytes are a type of cell that line air bags or alveoli of the lungs. Alveoles are the site of gas exchange in the body, which concerns the process in which the oxygen is drawn from the inhalation air into the bloodstream and carbon dioxide (CO2) is removed from the blood and exhaled. Pneumocytes mainly act by supporting alveoli functions and can be divided into two subtypes: type I and type II.

type I pneumocytes are long and thin cells that are flattened above a large area, and therefore represent approximately 95 percent of the alveolar surface area, although they represent only about 40 percent of the actual cells. These cells form the structure of alveolar walls, allow the replacement of oxygen and carbon dioxide in the alveoli and help control the movement of the fluid between the interstitium and the air space. The this cells of these cells make them particularly susceptible to mechanical or toxic damage and lack mitotic potential and are regenerating from this.

The second type of alveolar cells, type II pneumocytes, are small, plump cells that represent approximately 3 percent of alveolar surface and are about 60 percent of real cells. Unlike type I cells, these cells have a mitotic potential that allows them to proliferate and distinguish themselves into type I key cells, and replace them after injury. An important function of type II cells is the production and secretion of the pulmonary surface -active substance - a liquid that covers the air bags and reduces the amount of work required by the lungs for breathing.

lung surface active substance is a protein and phospholipid mixture that completely stretches alveoli and contributes to the elasticity of the lungs. Two main function of the lung surface is to increase the ability of the lung gas and reduce alveoli surface tension, which reduces the amount of effort required to inflate the lungs during inspiration. If the lungs have insufficiency of this fluid, they may be susceptible to partial or complete collapse - alsoKnown as atectaze.

dust cells or alveolar macrophages are a phagocytic type of cell located near pneumocytes. They are located on the main border between the body and the outside world - an area where the host is particularly vulnerable to the invasion of pathogens, toxins and foreign substances - and the host defense is their primary function. Dust cells usually respond to foreign substances of absorbing and digestion; However, in the case of a threat that is too large to be controlled only by phagocytosis, these cells are also able to release a number of pro -inflammatory cytokines to cause a greater immune response of the body.