A phagocyte is a biological cell that ingests and destroys foreign matter such as microorganisms and debris by a process called phagocytosis. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually Phagocytosis is the cellular process of engulfing solid particles by the Cell membrane to form an internal Phagosome, or "food vacuole The term means "cell eater" in Greek. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly
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Types
There are three main categories of phagocytes: [1]
- macrophages (and monocytes)
- microphages, such as polymorphonuclear leukocytes (primarily neutrophils)
- dendritic cells
Functions
Phagocytes eat pathogens and are extremely useful as an initial immune system response to infection. Macrophages ( Greek: "big eaters" from makros "large" + phagein "eat" ( Mø) are cells within the tissues that Monocyte is a type of Leukocyte, part of the Human body 's Immune system. Granulocytes are a category of White blood cells characterised by Neutrophil granulocytes, generally referred to as neutrophils, are the most abundant type of White blood cells in humans and form an essential part of the An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor An infection is the detrimental Colonization of a host Organism by a foreign Species. They contain many lysosomes that enable them to digest foreign material. Lysosomes are Organelles that contain Digestive enzymes (acid Hydrolases. They engulf pathogens, debris, dead or dying cells and extracellular matrix. A pathogen (from Greek πάθος pathos "suffering passion" and γἰγνομαι (γεν- gignomai (gen- "I give birth to" infectious In Biology, the extracellular matrix ( ECM) is the Extracellular part of animal tissue that usually provides structural support to the cells After engulfment into a phagosome, a lysosome which is filled with digestive enzymes (proteases and oxygen radicals) fuses with it to form the phagolysosome in which the phagocytosed material is digested. In cell biology a phagosome is a Vacuole formed around a particle absorbed by Phagocytosis. Lysosomes are Organelles that contain Digestive enzymes (acid Hydrolases. A protease is any Enzyme that conducts Proteolysis, that is begins protein Catabolism by Hydrolysis of the Peptide bonds that link In Chemistry, radicals (often referred to as free radicals) are atoms molecules or ions with Unpaired electrons on an otherwise Open shell A phagolysosome is a membrane-enclosed Organelle which is formed from the fusing of a Lysosome and a Phagosome.
If the skin is broken, the first type of phagocyte that migrate to sites of injury are neutrophils. The skin is the outer covering of living tissue of an animal (or plant They fight bacteria by releasing cytotoxic granules and by phagocytosis. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Cytotoxicity is the quality of being toxic to cells Examples of toxic agents are a Chemical substance, an Immune cell or some types of Venom Phagocytosis is an active process in wound healing. In Medicine, a wound is a type of Injury in which the Skin is torn cut or punctured (an open wound or where blunt force trauma Healing, assessed physically is the process by which the cells in the Body regenerate and repair to reduce the size of a damaged or necrotic area
In pathogen phagocytosis, specialised antigen-presenting cells (B cells, dendritic cells and macrophages) present on their surfaces small peptides that resulted from the digestion, bound to MHC class II molecules. See also Antigen presentation An antigen-presenting cell ( APC) or accessory cell is a cell that displays foreign Antigen complexed B cells are Lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response, which is governed by Dendritic cells (DCs are Immune cells and form part of the Mammalian Immune system. Macrophages ( Greek: "big eaters" from makros "large" + phagein "eat" ( Mø) are cells within the tissues that Peptides (from the Greek πεπτίδια, "small digestibles" are short Polymers formed from the linking in a defined order of α- Amino MHC ( Major histocompatibility complex) Class II molecules are found only on a few specialized cell types including Macrophages Dendritic cells and In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by Helper T cells (CD4+) later recognize these antigens complemented with a second signal, and supplement the cell-mediated immune response. T helper cells (also known as effector T cells or Th cells) are a sub-group of Lymphocytes (a type of White blood cell or An antigen (from antibody-generating) or immunogen is a substance that prompts the generation of Antibodies and can cause an immune response
Phagocytes can also induce apoptosis of normal and tumor cells, produce cationic proteins, complement components and clotting factors, arachidonic acid metabolites, prostaglandins, leukotrienes, thromboxanes, cytokines, proteases and hydrolases, reactive oxygen and nitrogen intermediates. See also Cancer A tumor or tumour is the name for a swelling or lesion formed by an abnormal growth of cells (termed neoplastic An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Coagulation is a complex process by which Blood forms Clots It is an important part of Hemostasis (the cessation of blood loss from a damaged vessel whereby Arachidonic acid (AA sometimes ARA is an Omega-6 fatty acid 204(ω-6 A prostaglandin is any member of a group of Lipid compounds that are derived enzymatically from Fatty acids and have important functions in the Animal body Leukotrienes are naturally produced Eicosanoid lipid mediators, which may be responsible for the effects of an inflammatory response Thromboxane is a member of the family of Lipids known as Eicosanoids. Cytokines are a category of signalling Proteins and Glycoproteins that like Hormones and Neurotransmitters, are used extensively in cellular In Biochemistry, a hydrolase is an Enzyme that catalyzes the Hydrolysis of a Chemical bond. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14
Resistance by pathogen
Many pathogens can delay or prevent the creation of the phagolysosome such as Mycobacterium tuberculosis, Salmonella typhi and Legionella. Mycobacterium tuberculosis is the Bacterium that causes most cases of Tuberculosis. Salmonella enterica is a rod shaped Flagellated Gram-negative Bacterium, and a member of the Genus Salmonella Legionella is a Gram negative Bacterium, including species that cause Legionellosis or Legionnaires' disease most notably L Others, such as the parasites of the genus Leishmania, able to resist or circumvent being digested in the phagolysosome. Parasitism is a type of symbiotic relationship between Organisms of different Species. Leishmania is a Genus of Trypanosome Protozoa, and is the Parasite responsible for the disease Leishmaniasis.
One function of T-helper cells is to activate phagocytes to digest intracellular pathogens.
Etymology
The word phagocyte means "cell that eats", and originates from the Greek words phagein, meaning 'eat', and kytos, meaning 'hollow'.
References
External links
eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and booksDictionary
phagocyte
-noun
- (cytology) A cell of the immune system, such as a neutrophil, macrophage or dendritic cell, that engulfs and destroys viruses, bacteria and waste materials, or in the case of mature dendritic cells; displays antigens from invading pathogens to cells of the lymphoid lineage.
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