Activating The Pineal Gland Pdf File' title='Activating The Pineal Gland Pdf File' />Phagocyte Wikipedia.Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells.Their name comes from the Greekphagein, to eat or devour, and cyte, the suffix in biology denoting cell, from the Greek kutos, hollow vessel.They are essential for fighting infections and for subsequent immunity.Phagocytes are important throughout the animal kingdom3 and are highly developed within vertebrates.One litre of human blood contains about six billion phagocytes.They were discovered in 1.Ilya Ilyich Mechnikov while he was studying starfishlarvae.Mechnikov was awarded the 1.Nobel Prize in Physiology or Medicine for his discovery.Phagocytes occur in many species some amoebae behave like macrophage phagocytes, which suggests that phagocytes appeared early in the evolution of life.Phagocytes of humans and other animals are called professional or non professional depending on how effective they are at phagocytosis.The professional phagocytes include many types of white blood cells such as neutrophils, monocytes, macrophages, mast cells, and dendritic cells.Activating The Pineal Gland Pdf File' title='Activating The Pineal Gland Pdf File' />The killing of microbes is a critical function of phagocytes that is performed either within the phagocyte intracellular killing or outside of the phagocyte.Melatonin, also known as Nacetyl5methoxy tryptamine, is a hormone that is produced by the pineal gland in animals and regulates sleep and wakefulness.Melatonin is. The main difference between professional and non professional phagocytes is that the professional phagocytes have molecules called receptors on their surfaces that can detect harmful objects, such as bacteria, that are not normally found in the body.Phagocytes are crucial in fighting infections, as well as in maintaining healthy tissues by removing dead and dying cells that have reached the end of their lifespan.During an infection, chemical signals attract phagocytes to places where the pathogen has invaded the body.These chemicals may come from bacteria or from other phagocytes already present.The phagocytes move by a method called chemotaxis.When phagocytes come into contact with bacteria, the receptors on the phagocytes surface will bind to them.This binding will lead to the engulfing of the bacteria by the phagocyte. Download Advanced Systemcare 4 Crack there. Some phagocytes kill the ingested pathogen with oxidants and nitric oxide.After phagocytosis, macrophages and dendritic cells can also participate in antigen presentation, a process in which a phagocyte moves parts of the ingested material back to its surface.This material is then displayed to other cells of the immune system.Some phagocytes then travel to the bodys lymph nodes and display the material to white blood cells called lymphocytes.This process is important in building immunity,1.Historyedit. Ilya Ilyich Mechnikov in his laboratory.The Russian zoologist Ilya Ilyich Mechnikov 1.In 1. 88. 2, he studied motile freely moving cells in the larvae of starfishes, believing they were important to the animals immune defenses.To test his idea, he inserted small thorns from a tangerine tree into the larvae.After a few hours he noticed that the motile cells had surrounded the thorns.Mechnikov traveled to Vienna and shared his ideas with Carl Friedrich Claus who suggested the name phagocyte from the Greek words phagein, meaning to eat or devour, and kutos, meaning hollow vessel1 for the cells that Mechnikov had observed.A year later, Mechnikov studied a fresh water crustacean called Daphnia, a tiny transparent animal that can be examined directly under a microscope.Activating The Pineal Gland Pdf File' title='Activating The Pineal Gland Pdf File' />He discovered that fungal spores that attacked the animal were destroyed by phagocytes.He went on to extend his observations to the white blood cells of mammals and discovered that the bacterium.Bacillus anthracis could be engulfed and killed by phagocytes, a process that he called phagocytosis.Mechnikov proposed that phagocytes were a primary defense against invading organisms.In 1. 90. 3, Almroth Wright discovered that phagocytosis was reinforced by specific antibodies that he called opsonins, from the Greek opson, a dressing or relish.Mechnikov was awarded jointly with Paul Ehrlich the 1.Nobel Prize in Physiology or Medicine for his work on phagocytes and phagocytosis.Although the importance of these discoveries slowly gained acceptance during the early twentieth century, the intricate relationships between phagocytes and all the other components of the immune system were not known until the 1.Phagocytosisedit.Phagocytosis in three steps 1.Unbound phagocyte surface receptors do not trigger phagocytosis.Binding of receptors causes them to cluster.Phagocytosis is triggered and the particle is taken up by the phagocyte.Phagocytosis is the process of taking in particles such as bacteria, parasites, dead host cells, and cellular and foreign debris by a cell.It involves a chain of molecular processes.Phagocytosis occurs after the foreign body, a bacterial cell, for example, has bound to molecules called receptors that are on the surface of the phagocyte.The phagocyte then stretches itself around the bacterium and engulfs it.Phagocytosis of bacteria by human neutrophils takes on average nine minutes.Once inside this phagocyte, the bacterium is trapped in a compartment called a phagosome.Within one minute the phagosome merges with either a lysosome or a granule to form a phagolysosome.The bacterium is then subjected to an overwhelming array of killing mechanisms2.Dendritic cells and macrophages are not so fast, and phagocytosis can take many hours in these cells.Macrophages are slow and untidy eaters they engulf huge quantities of material and frequently release some undigested back into the tissues.This debris serves as a signal to recruit more phagocytes from the blood.Phagocytes have voracious appetites scientists have even fed macrophages with iron filings and then used a small magnet to separate them from other cells.Macrophages have special receptors that enhance phagocytosis not to scaleA phagocyte has many types of receptors on its surface that are used to bind material.They include opsonin receptors, scavenger receptors, and Toll like receptors.Opsonin receptors increase the phagocytosis of bacteria that have been coated with immunoglobulin G Ig.G antibodies or with complement.Complement is the name given to a complex series of protein molecules found in the blood that destroy cells or mark them for destruction.Scavenger receptors bind to a large range of molecules on the surface of bacterial cells, and Toll like receptorsso called because of their similarity to well studied receptors in fruit flies that are encoded by the Toll genebind to more specific molecules.Binding to Toll like receptors increases phagocytosis and causes the phagocyte to release a group of hormones that cause inflammation.Methods of killingedit.Simplified diagram of the phagocytosis and destruction of a bacterial cell.The killing of microbes is a critical function of phagocytes2.Oxygen dependent intracellulareditWhen a phagocyte ingests bacteria or any material, its oxygen consumption increases.The increase in oxygen consumption, called a respiratory burst, produces reactive oxygen containing molecules that are anti microbial.The oxygen compounds are toxic to both the invader and the cell itself, so they are kept in compartments inside the cell.This method of killing invading microbes by using the reactive oxygen containing molecules is referred to as oxygen dependent intracellular killing, of which there are two types.The first type is the oxygen dependent production of a superoxide,2 which is an oxygen rich bacteria killing substance.The superoxide is converted to hydrogen peroxide and singlet oxygen by an enzyme called superoxide dismutase.Superoxides also react with the hydrogen peroxide to produce hydroxyl radicals, which assist in killing the invading microbe.The second type involves the use of the enzyme myeloperoxidase from neutrophil granules.When granules fuse with a phagosome, myeloperoxidase is released into the phagolysosome, and this enzyme uses hydrogen peroxide and chlorine to create hypochlorite, a substance used in domestic bleach.Hypochlorite is extremely toxic to bacteria.Myeloperoxidase contains a heme pigment, which accounts for the green color of secretions rich in neutrophils, such as pus and infected sputum.Oxygen independent intracellulareditPhagocytes can also kill microbes by oxygen independent methods, but these are not as effective as the oxygen dependent ones.There are four main types.The first uses electrically charged proteins that damage the bacteriums membrane.
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