Both are caused by chemical, physical or biological agents. Jun 11, 2015 this topic covers the mechanism of irreversible cell injury. Different mechanisms of cell injury cell injury by atp depletion cell injury by mitochondrial damage cell injury by increased cytosolic calcium cell injury by reactive oxygen species. This topic covers the mechanism of irreversible cell injury. Cellular function is lost far before cell death occurs, and the morphologic changes of cell injury or death lag far behind both.
Etiology of cell injury free download as powerpoint presentation. Different mechanisms of cell injury cell injury by atp depletion cell injury by mitochondrial damage cell injury by increased cytosolic calcium cell injury. The slide includes a transmural section of the left ventricle. Define and understand the morphologic patterns of lethal cell injury and the clinical settings in which they occur. For example, atrophy of the brain in alzheimer disease is secondary to. Cell death by injurious stimuli cell injury from virusesatrophy from duct obstruction cell death in tumors remember that necrosis is only pathologic while apoptosis can be both pathologic and physiologic. Chapter 4 cell injury, aging, and death jacquelyn l. At the cellular level, there are many processes that can lead to.
Fatty change encountered in cells invloved in fat metabolism hepatocyte, myocardium. Download as ppt, pdf, txt or read online from scribd. Reversible responses also known as repair mechanisms may represent the early stages of irreversible injury or may be sustained where the cell achieves a new steady state. Pdf on aug 1, 1996, j p cobb and others published mechanisms of cell injury and death find, read and cite all the research you. When cell death occurs in the living body, the term necrosis is used.
Regain access you can regain access to a recent pay per article purchase if your access period has not yet expired. May 30, 2014 an animated overview of the reversible changes that take place following cell injury. Cell injury it is change in cells morphology and function in response to stress. When cells are injured, one of two patterns will generally result. Cellular response for reversible and irreversible cell. Cellular swelling appears whenever cells are incapable of maintaining ionic and fluid homeostasis and is the result of loss of function of plasma membrane energydependent ion pumps. In coronary arteries, myocardial contractility is reversed if circulation is quickly restored. Cell injury, adaptation, and necrosis apoptosis and beyond wiley. Chapter 1 cellular responses to stress and toxic insults. Contrast ischemia in skeletal muscle tolerates 2 hours versus cardiac muscle tolerate 20. Pdf on mar 26, 2019, wasfi abid ali and others published cell damage find, read and cite all the. Hypoxia is the most important cause of cell injury.
The causes of cell injury, reversible or irreversible, may be broadly classified into two large groups. Adaptation change in cell morphology and function in response to a stimulus. Recovery reversible cell injury can be treated with drugs while irreversible cell injury leads to permanent cell loss. Banasik chapter outline reversible cell injury, 58 hydropic swelling, 58 intracellular accumulations, 58 cellular adaptation, 60 atrophy, 60 hypertrophy, 61 hyperplasia, 61 metaplasia, 61 dysplasia, 62 irreversible cell injury, 62 necrosis, 62 apoptosis, 64 etiology of cellular injury, 66 ischemia and hypoxic injury, 66 nutritional injury. Types of reversible changes resulting from cell injury, including ion deregulation and induction of immediateearly genes, may be responsible for cells reentering the. Adaptation, injury, and death 5 cytoplasmic changes described later. Discriminate cell adaptation, reversible cell injury and irreversible cell injury cell death based on etiology, pathogenesis and histological and ultrastructural appearance. Morphological changes follow functional changes o reversible injury. Introduction cell injury is defined as a variety of stresses a cell encounters as a result of.
Cell has various mechanisms to prevent cell injury by free radicals vit c, glutathione peroxidase, cerruloplasmin, etc. Adaptation and reversible injury patterns of tissue necrosis. Irreversible cell injury results in complete cell death and normal cellular conditions cannot be achieved even if the stress is relieved. Overview of cell injury cells actively control the composition of their. Chapter 1 cellular adaptations, cell injury, and cell death 5 if the limits of adaptive response to a stimulus are exceeded, or in certain instances when the cell is exposed to an injurious agent or stress, a sequence of events follows that is loosely termed cell injury. Reversible cell injury is usually the result of the beginning stages of lack of oxygen, also known as hypoxia, or ischemia, the lack of blood flow to cells, while irreversible cell injury involves more insidious agents such as viruses, immunological responses, or genetic disadvantages. If the adaptive capability is exceeded or if the external stress is inherently harmful, cell injury develops fig. Extremely important common cause of cell injurycell death. The adaptation may be physiologic normal or pathologic abnormal. Reversible injury nonlethal irreversible injury cell death. Cellular function is lost far before cell death occurs, and the morphologic changes of cell injury. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This presentation helps you in understanding the basic concepts of cell injury. This is the key difference between reversible and irreversible cell injury.
It also depends upon the organ which undergoes hypoxia. Fatty change occurs in hypoxic injury and various forms. In adult tissues, the size of a cell population is determined by the rates of cell differentiation, proliferation, and death by apoptosis. Being inhibited by low ph, the mpt pore is kept quiescent during ischemia. Cell injury is classified as reversible if the injured cell can regain homeostasis and return to a morphologically and functionally normal state. However, there is a thin rim 5 to 10 cell layers of endocardial myocytes which have survived because of diffusion of oxygen and nutrients from the ventricular cavity. Depending on the extent of injury, the cellular response may be adaptive and where possible, homeostasis is restored. Irreversible cell injury can be recognized by changes in the appearance of the nucleus and rupture of the cell membrane. The main mechanism of cell injury involves the formation of free radicals and examples include carbon tetrachloride ccl 4once widely used in the dry cleaning industry but now bannedand the analgesic acetaminophen ccl 4 is converted to the toxic free radical principally in the liver, and this free radical is the cause of cell injury. Two patterns of reversible cell injury can be recognized under the light microscope. Sep 21, 2017 reversible cell injury results in morphological and cellular changes that could be reversed if the stress is taken off. Oxygen deprivation to tissue ischemia leading to a form of tissue damage termed an infarct is of notable clinical significance e. Damage to pm influx of ca, na and h2o swelling inactivation of mt, cell enzymes and denaturation of proteins so far, two reasons for fatty liver alcoholism and ccl4 poisoning note. Reports of amelioration of myocardial metabolic and ischemic injury with caspase inhibitors have appeared.
Adaptation, reversible injury, and cell deathcan be considered. Full text get a printable copy pdf file of the complete article 2. Thus, cell death is a normal physiological process as well as a reaction to injury. Metaplasia is a reversible change in which one adult cell type is replaced by another adult cell type metaplasia is a cellular adaptation in which.
Notably, well focus in on the different types of necrosis that may occur in the body, their causes, and what. Reversible injury may require cellular adaptation but the cell survives. I will discuss histological changes in cells, cellular. They have the ability to resist these different external and internal stress stimuli. Free radical damage occurs when these defense mechanisms are overcome, i. The pathogenesis of cell injury is discussed in great detail. Just like bones, muscles and skin, your cells too can become injured. Cells undergo many adaptations in response to different environmental, physiological and chemical stimuli. Cell damage also known as cell injury is a variety of changes of stress that a cell suffers due to external as well as internal environmental changes. In this video we have discussed the different mechanisms of cell injury. When cells adapt to injury, their adaptive changes can be. Mechanism of irreversible cell injury the art of medicine. Fatty change occurs in hypoxic injury and various forms of.
What is the difference between reversible and irreversible. Four types of morphological adaptations include atrophy, hypertrophy, hyperplasia, and. Cellular swelling is the result of failure of energydependent ion pumps in the plasma membrane, leading to an inability to maintain ionic and fluid homeostasis. Irreversible injury an overview sciencedirect topics. This lesson will discuss the different causes and types of irreversible cell injury. Pathology ischemic changeseg, of the myocardium, that can be reversed with timely return of normal circulation to the tissue of interest. In the following quiz on cells, well be looking at how all of this can occur and what the processes are behind it. Cell death occurs when the severity of the injury exceeds the cell s ability to repair itself. Conclusion reversible cell injury is a condition that can return to the steady state. Reduction in an organs size may reflect reversible cell at rophy or irreversible loss of cells. Cell injury may be reversible sublethal or irreversible lethal. What do you know about the ins and outs of cell injury, as well as what causes there are and what preventative measures can be taken. Injury may progress through a reversible stage and culminate in cellular death.
Reversible injury definition of reversible injury by. Cell injury, cell death, and adaptations new age medical. Cell injury occurs when the limits to an adaptive response adaptation have been exceeded or if the cells are not able to adapt. This dynamic state occurs in tissues such as the bone marrow, skin. The stronger and the longer the stimulus, the larger the damage response to a given stimulus depends on the type, status, and genetic makeup of the injured cell. Opening of the mpt pore in the inner mitochondrial membrane is a critical event in the progression of cell death in response to ir. Cell injury is reversible up to a certain point, but if the stimulus persists or is severe enough from the beginning, the cell reaches a point of no return and suffers irreversible cell injury and ultimately cell death. In cell biology and pathophysiology, cellular adaptation refers to changes made by a cell in response to adverse or varying environmental changes. Adaptation and reversible injury patterns of tissue. It is an intracytoplasmic accumulation of water due to incapacity of the cells to maintain the ionic and fluid homeostasis.
This chapter will present an overview of how the pathologist views mechanisms of irreversible cell injury cell death, reversible cell injury, and the organisms response to both. Irreversible cell injury hypoxia massive ca influx, and enzyme activation entry of extracellular macromolecules into the dying cells the dead cell may become replaced by large masses composed of phospholipids in form of myelin figures calcification may occur leakage of enzymes in plasma. Key difference reversible vs irreversible cell injury cells are the main functional and structural units of living organisms. Cell injury may be reversible nonlethal damage which generally can be. Modes of myocardial cell injury and cell death in ischemic. This disorder in phospholipid metabolism is felt to be the critical lesion that produces irreversible cell injury. Acquired causes of cell injury further categorized as given, a. Introduction cell injury is defined as a variety of stresses a cell encounters as a result of changes in its internal and external environment. However, cell replication proceeds in a human body at a rate of c. Reversible cell injury results in cellular swelling and fat accumulation while irreversible cell injury results in necrosis and apoptosis. Cell injury it is change in cell s morphology and function in response to stress.
Cell response to injury is not an allornothing phenomenon. Causes of cell injury the causes of cell injury range from the external gross physical violence of an automobile accident to subtle internal abnormalities, such as a genetic mutation causing lack of a vital enzyme that impairs normal metabolic function. May 20, 2016 this presentation helps you in understanding the basic concepts of cell injury. Costa path learn with flashcards, games, and more for free. Pdf mechanisms of cell injury and death researchgate. Both reversible and irreversible cell injuries occur when stress acts upon cells. The first topic, reversible cell injury, covers the physiology and pathology of reversible cell injuries, and what happens to a cell when a cell is unable to adapt to the stresses of the environment. Sublethal injury apply knowledge of cellular physiology, metabolism, and macromolecular synthesis to discuss cellular and subcellular responses to sublethal injury or stress on cells. Role of mitochondria in ischemiareperfusioninduced cell injury. Within certain limits injury is reversible, and cells return to a stable baseline. Amongst other causes, this can be due to physical, chemical, infectious, biological, nutritional or immunological factors. Irreversible cell injury what are the similarities between reversible and irreversible cell injury. Reversible and irreversible cellular injury and necrosis dr. Cell injury results when cells are stressed so severely that they are no longer able to adapt or when cells are exposed to inherently damaging agents.
Acute cell swelling is the classic morphologic change in reversible injury. Reversible cell injury pdf the syllabus for cell injury and cell death covers the material to be presented at the. Difference between reversible and irreversible cell injury. If ischemia or hypoxia is for short period of time, the cell can be reverting back to its normal condition which is known as rci.
Key concepts contd cell injury can be reversible or irreversible. These alterations may be divided into the following stages. Reversible cell injury the two main morphologic correlates of reversible cell injury are cellular swelling and fatty change. Too much stress exceeds the cells adaptive capacity. Ex, skeletal muscle can with stand for half an hour with. Acquired causes of cell injury further categorized as. Irreversible cell injury various forms of cell injury. At the cellular level, there are many processes that can lead to necrosis. Pathologic cell injury and cell death i mechanism of. Cell injury, adaptation and death mit opencourseware. The stronger and the longer the stimulus, the larger the damage. May 29, 2015 pathologic cell injury and cell death i mechanism of reversible cell injuries pathologic cell injury and cell death i mechanism of reversible cell injury we already know that cells are able to adapt to their surroundings when there is an increased amount of stress to overcome them, just as we will in all our medical exams.
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