how is the mechanism of the repairement of pericyte cells?
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link below gives info
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Keep in mind that necrosis is different from cell apoptosis.  \n\nApoptosis is "programmed cell death" where the cell actually will undergo extra protein synthesis in order to make the proteins for a rather organized cell death.  The cell essentially becomes a bunch of little vesicles that are eaten up by nearby phagocytic cells.  \n\nNecrosis occurs when the cell kinda falls apart.  It realeases a whole bunch of "crud" into the system that results in inflammation.  \nThere are whole protein cascades and signalling pathways that control these events.  But, in an overview, necrosis occurs in two general steps.  \n\n1. Chromatin clump up, and organelles begin to swell up.\n2. Plasma membrane breaks down, and the cell disintigrates.  The resulting debris can cause inflammation.
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They react with oxidant molecules and free radicals that are present inside your body. Highly oxidant molecules otherwise react with proteins and cellular components, that can damage cells.\n\nSo antioxidants help to protect your cells.
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What Is It?\n\nLangerhans' cells are white blood cells in the immune system that normally play an important role in protecting the body against viruses, bacteria and other invaders. They are found in the skin, lymph nodes, spleen, bone marrow and lungs.\n\nIn Langerhans' cell histiocytosis (formerly known as histiocytosis X), Langerhans' cells multiply abnormally. Instead of helping to protect the body, these cells, in massive numbers, cause tissue injury and destruction, especially in the bones, lungs and liver. Although this overgrowth of cells may be like cancer, most researchers do not consider Langerhans' cell histiocytosis to be a form of cancer. In fact, the cells appear to be normal. There are just too many of them.\n\nLangerhans' cell histiocytosis can develop in only one site or organ, or it can involve several different sites and organs. In most cases, Langerhans' cell histiocytosis that affects many body systems typically occurs in children younger than 2, whereas single-site disease may occur in people of any age.\n\nThe cause of the disorder is unknown. However, researchers are studying the possibility that some common substance in the environment — perhaps a viral infection — may trigger the disease by causing the immune system to overreact. However, researchers have not yet identified an infection or substance that triggers the disease. One intriguing observation is that almost all people with the disease whose lungs are involved are current or former cigarette smokers. However, even among smokers, this condition is rare, and smoking seems to play no role in the disease when it affects parts of the body outside the lungs. Other theories suggest that the primary cause of Langerhans' cell hystiocytosis is an abnormal immune system.\n\nLangerhans' cell histiocytosis is rare, affecting one in 250,000 children and one in 1 million adults in the United States. Although it can strike at any age, it is most common in children and young adults, with about 70% of cases occurring before age 17. During childhood, Langerhans' cell histiocytosis peaks between ages 1 and 3.\n\nLangerhans' cell histiocytosis, includes disorders previously considered separate diseases: diffuse reticuloendotheliosis, eosinophilic granuloma, Hand-Schuller-Christian disease and Letterer-Siwe disease.\n\nSymptoms\n\nSymptoms can include:\n\n    * Persistent pain and swelling on a bone, especially in an arm or leg\n    * A bone fracture, especially one that happens without any apparent trauma or after only a minor injury\n    * Loose teeth, if Langerhans' cell histiocytosis affects the jaw bones\n    * Ear infection or a discharge from the ear, if Langerhans' cell histiocytosis affects skull bones near the ear\n    * Skin rash, usually on the buttocks or scalp\n    * Swollen glands (enlarged lymph nodes)\n    * Enlarged liver, with or without signs of liver malfunction, such as yellowing of the skin and eyes (jaundice) and abnormal accumulation of fluid in the abdomen (ascites)\n    * Bulging eyes, caused by Langerhans' cell histiocytosis behind the eyes\n    * Shortness of breath and cough, if the lungs are involved\n    * Stunted growth and excessive urination caused by hormone abnormalities\n\nLess common symptoms include fever, weight loss, irritability and inability to maintain weight and fitness ("failure to thrive").\n\nDiagnosis\n\nBecause Langerhans' cell histiocytosis is rare and tends to cause symptoms that could be caused by more common medical problems, this disease often is difficult to diagnose, and diagnosis can take time. Because of this, your doctor may ask questions that are related to those other medical problems, rather than about Langerhans' cell histiocytosis.\n\nYour doctor will examine you, paying special attention to the areas of your body where you are having symptoms. If you have bone pain or swelling, your doctor probably will want you to have a se
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Measurement of cell proliferation and cell mediated contraction in 3-dimensional hydrated collagen matrices \n\nSummary  This report describes simplified methods for the preparation of reconstituted collagen gels containing a uniform distribution of anchorage dependent cells in 96-well microtitration plates, their dissolution with collagenase allow harvesting of either cells or medium, and objective analytical methods for measuring cell mediated contraction of collagen gels and [3 H]thymidine incorporation rates.\nKey words  collagen - cell proliferation assay - contraction assay - micro cell-culture methods\n\nTo whom requests for reprints should be addressed at Opthalmic Research Unit, University of Western Australia, Royal Perth Hospital, GPO Box X2213, PERTh 6001, Western Australia.\n\n:>peace
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(scroll to ">>>>>>")\nFor every cell, there is a time to live and a time to die. \nThere are two ways in which cells die: \nThey are killed by injurious agents. \nThey are induced to commit suicide.\nDeath by injury\nCells that are damaged by injury, such as by \nmechanical damage \nexposure to toxic chemicals\nundergo a characteristic series of changes: \nThey (and their organelles like mitochondria) swell (because the ability of the plasma membrane to control the passage of ions and water is disrupted). \nThe cell contents leak out, leading to \ninflammation of surrounding tissues.\nDeath by suicide\nCells that are induced to commit suicide: \nshrink; \ndevelop bubble-like blebs on their surface; \nhave the chromatin (DNA and protein) in their nucleus degraded; \nhave their mitochondria break down with the release of cytochrome c; \nbreak into small, membrane-wrapped, fragments. \nThe phospholipid phosphatidylserine, which is normally hidden within the plasma membrane, is exposed on the surface. \nThis is bound by receptors on phagocytic cells like macrophages and dendritic cells which then engulf the cell fragments. \nThe phagocytic cells secrete cytokines that inhibit inflammation (e.g., IL-10 and TGF-β)\nThe pattern of events in death by suicide is so orderly that the process is often called programmed cell death or PCD. The cellular machinery of programmed cell death turns out to be as intrinsic to the cell as, say, mitosis. \n\nProgrammed cell death is also called apoptosis.\n\n1. Programmed cell death is as needed for proper development as mitosis is. \nExamples: \nThe resorption of the tadpole tail at the time of its metamorphosis into a frog occurs by apoptosis. \n>>>>>>>>The formation of the fingers and toes of the fetus requires the removal, by apoptosis, of the tissue between them. \nThe sloughing off of the inner lining of the uterus (the endometrium) at the start of menstruation occurs by apoptosis. \nThe formation of the proper connections (synapses) between neurons in the brain requires that surplus cells be eliminated by apoptosis
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Membrane recycling is the process where the cell moves around its membrane and phospholipid molecules where it needs it most. There are both endocytosis and exocytosis which move the membrane (phospholipid bilayer) around. In endocytosis, large particles that can't diffuse through the membrane bind to receptor proteins on the surface of membrane. Then that area caves in when the ligand (whatever the molecules were) binds and pinches of forming a complete circle(sac) with the molecules ont the inside. These sacs called vesicles now move around inside the cell and may find places such as the Golgi Apparatus (which is also made of membrane) and may attach there. that moves membrane AWAY from the outer cell membrane to the inside. In exocytosis, membrane sacs (vesicles) are prepared in the Golgi Apparatus or other membrane oragnelles (in the same fahsion as they were in exocytosis except in different location) and they travel to the outer cell membrane. Here the vesicle slowly fuses with the plasma membrane (outer cell) and secretes the inside. Now the Phospholipid molecules that previously formed the vesicle noow becomes part of the plasma membrane. Sometimes blank or empty vesicles are sent ot plasma membran in order to enlargen it whether secretion takes place. This also applys to endocytosis.\n\nHope this helps and Good luck
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Melanocytes (cells in our skin) upon receiving signals of damage to DNA (due to UV radiation) begin producing melanin in large amounts.\nMelanin is a polymer that captures UV and thus protects cells from DNA damage.\nHair doesn't have melanocytes. It is made of keratin (protein) and minerals. So typical reaction will be - no change or in constant exposure to sun rays- damage to keratin and bleaching.
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Doesn't get much simpler than this website, have fun!\n\nhttp://www.biology4kids.com/files/cell_main.html
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I am guessing you are refering to putting peroxide on your skin to help heal a cut or open sore? If so, the burning you are feeling is coming from the water produced whent the peroxide breaks down. Here is how peroixde works for helping to stop infections. Peroxide is an unstable molecule (H2O2) and breaks down into free Oxygen and Water when reacting with enzymes or light. This is why peroxide is always in dark plastic containers to prevent its breakdown. When you pour some on a cut, the enzymes in your body cause the peroxide to break down into water and oxygen. The high concentration of oxygen will kill a large varity of bacteria that can cause infection that might be in the cut. The burning you feel is because of the water produced gets absorbed into the surrounding cells and causes them to lyse or burst, causing pain. This is why getting water into any cut makes it burn. In your body your cells have a certian amount of water in them. If you put them in an envirnoment with MORE water on the outisde of them, the water will move inside the cells and cause them to swell and eventually burst. This is because the water on the inside of the cell and outside of the cell want to be the same concentration. The is called Osmosis.
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Cell regulation or gene regulation?\n\nIf it is cell regulation then mishaps can occur in the signals that trigger responses. Mutation in the receptors or signalling molecules of cells may cause certain pathways to be triggered by accident.\n\nGene regulation mishaps occur when the gene repair mechanism is damaged. Deletions, additions, translocations and inversion can occur in the gene sequence. Housekeeping genes make products that can repair the genes.
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free radicals are basically rogue particles that bounce around inside your cells, damaging your cells as they go.  This causes your cells to deteriorate over time, which in effect is the aging process.  Theoretically, eliminating some of them slows the damage rate, and the aging process as well.
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Cells that are undergoing constant mitosis such as hematopoetic stem cells (cells in your bone marrow that give rise to blood cells) and keratinocytes (skin cells) generally replicate in an ongoing manner about once a day, or faster.  I should say that it is only the skin cells of the bottom two layers of epidermis that undergo replication (stratum basale, and stratum spinosum).  Most of the replication occurs in the bottom layer of the epidermis (basale).\n\nMost of the time will be spent in the pre-mitotic cell cycle stages, G1, S, and G2, giving the cell ample time to replicate its DNA, and prepare for the division.  These stages are collectively referred to as 'interphase'.  The G1 phase varies (it will be at least 4 hours), the G2 phase lasts aroud 4-5 hours, and the S phase is usually around 6-8 hours (this is when the DNA is replicating).  So the entire interphase will be anywhere from 14-24 hours.\n\nThe mitotic process (the M phase) only takes about an hour.  Prophase is usually the longest phase of mitosis, and is in itself often broken down into a few different substages.  Once the metaphase stage begins, things move along pretty swiftly.  \n\nHope that helps!
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do you mean what processes cells must undergo? \n\nIf that's your question, then the processes would be cell division by mitosis (to produce more cells, so that organism can increase in size/length), cell elongation(this occurs mainly in plants via vacuolation and thus aids in increase in size and length) and cell differentiation(this allows genes to be switched on or off so that certain traits/phenotypes can be expressed, eg. gene that codes for blue eyes switched on for cell in the eye and not elsewhere like cell on the hand/feet). Hope this answers your question.
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http://en.wikipedia.org/wiki/Human_cells
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Stem cells are primal undifferentiated cells which retain the ability to differentiate into other cell types. This ability allows them to act as a repair system for the body, replenishing other cells as long as the organism is alive.\n\nMedical researchers believe stem cell research has the potential to change the face of human disease by being used to repair specific tissues or to grow organs. Yet as government reports point out, "significant technical hurdles remain that will only be overcome through years of intensive research."[1]\n\nThe study of stem cells is attributed as beginning in the 1960s after research by Canadian scientists Ernest A. McCulloch and James E. Till.\n\nStem Cell Types\n\nPotency\nStem cells are categorized by potency, which specifies the ameliorative potential of the cell type.\n\nTotipotent stem cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg cell are also totipotent. These cells can grow into any type of cell without exception. \nPluripotent stem cells are the descendants of totipotent cells and can grow into any cell type except for totipotent stem cells. \nMultipotent stem cells can produce only cells of a closely related family of cells (e.g. blood cells such as red blood cells, white blood cells and platelets). \nUnipotent cells can produce only one cell type, but have the property of self-renewal which distinguishes them from non-stem cells. \n\nSources of stem cells\n\nStem cells are also categorized according to their source, as either adult, embryonic or cord blood stem cells.\n\nAdult stem cells are undifferentiated cells found among differentiated cells of a specific tissue and are mostly multipotent cells. They are already being used in treatments for over one hundred diseases and conditions. They are more accurately called somatic (Greek σωμα sōma = body) stem cells, because they need not come from adults but can also come from children or umbilical cords. Particularly interesting are adult stem cells termed "spore-like cells". They are present in all tissues (Vacanti, M. P., A. Roy, J. Cortiella, L. Bonassar, and C. A. Vacanti. 2001. "Identification and initial characterization of spore-like cells in adult mammals." J Cell Biochem 80:455–60.) and seem to survive long time periods and harsh conditions. \nEmbryonic stem cells are cultured cells obtained from the undifferentiated inner mass cells of an early stage human embryo (sometimes called a blastocyst, which is an embryo that is between 50 to 150 cells). Embryonic stem cell research is "thought to have much greater developmental potential than adult stem cells," according to the National Institutes of Health.[2] However, embryonic stem cell research is still in the basic research phase, as these stem cells were first isolated in 1998 (at least for humans), whereas adult stem cells have been studied since the 1960s.[3] Research with embryonic stem cells derived from humans is controversial because, in order to start a stem cell 'line' or lineage, it requires the destruction of a human embryo and/or therapeutic cloning, which some believe is a slippery slope to reproductive cloning and tantamount to the objectification of a potential human being. In an attempt to overcome these moral, political and ethical hurdles, medical researchers have been experimenting with alternative techniques of obtaining embryonic stem cells by extraction, which does not involve cloning and/or the destruction of a human embryo. \nCord blood stem cells are derived from the blood of the placenta and umbilical cord after birth. Since 1988 these cord blood stem cells have been used to treat Gunther's disease, Hunter syndrome, Hurler syndrome, Acute lymphocytic leukemia and many more problems occurring mostly in children. Umbilical cord blood use has become so common that there are now umbilical cord blood banks that accept dona
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hydrogen peroxide slowly breaks down into water and oxygen. blood contains a catalyst called catalase. when the hydrogen peroxide comes in contact with catalase, it speeds up the breakdown. you are basically seeing oxygen breaking apart from water. sunlight also speeds up the reaction. (thats why it comes in a brown container);)