Cell damage is a variety of changes of stress that a cell suffers due to external as well as. Finally, cell death is caused by severe or prolonged injury. Insults due to hypoxia or ischemia chemical cell injury. Young people can respond better to injury than old. This presentation helps you in understanding the basic concepts of cell injury. Hypoxic ischemic injury, free radical induced, chemical injury, reversible, irreversible, ischemia reperfusion injury, free radical removal mechanisms, f.
She is treated with a chemotherapeutic agent which results in the loss of individual neoplastic cells through fragmentation of individual cell nuclei and cytoplasm. Response to chronic irritation or low grade injury takes time, not an overnight development generally columnar is converted to squamous a tougher actor a form of genetic reprogramming respiratory epithelium of smoker goes to squamous. Another form of cell death as a result of irreversible injury is known as liquefactive necrosis. Capable of causing cell injury include mechanical trauma, extremes of temperature burns and deep cold, sudden changes in atmospheric pressure, radiation, and electric shock. Irreversible cell injury is characterised by a dispersion of ribosomes b cell swelling c nuclear chromatin clumping d lysosomal rupture e cell membrane defects 11. Amongst other causes, this can be due to physical, chemical, infectious, biological, nutritional or immunological factors.
Pathology c601 cellular injury and cell death cellular. When theres not enough atp around, the cell membrane pumps dont work well, and sodium and calcium accumulate inside the cell. The pathogenesis of cell injury is discussed in great detail. Cellular injury during cardiac arrest is principally mediated by oxygen deprivation, but additional neurologic injury is incurred depending on associated factors such as concomitant toxic exposures such as carbon monoxide, metabolic stressors such as hypoglycemia, and freeradical production after restoration of. In this tutorial, i have discussed pathogenesis of cell injury foll. Cellular response to injury apply knowledge of membrane physiology, metabolism, signal transduction and macromolecular synthesis to discuss cellular responses to injury at the cell, tissue and organism levels.
Cell injury results from different chemical mechanisms that act on several cellular componentsamong these are depletion of atp mitochondrial damage influx of calcium and loss of calcium homeostasis accumulation of oxygenderived free radicals oxidative stress defects in membrane permeability cell injury results from different chemical mechanisms that act on several cellular components. Mitochondrial changes are seen as vacuoles membrane bound organellein the mitochondria and deposit of amorphous calcium salts in mitochondrial matrix 9. I hope that you will enjoy studying these topics, as i do teaching this material, which is. In this example, hepatocytes are dying individually arrows from injury through infection by viral hepatitis.
Mechanism of irreversible cell injury the art of medicine. Answer liver injury from nonalcoholic fatty liver disease is a consequence of diabetes mellitus, metabolic syndrome, and obesity. G1 cell activities and centrioles replicate s dna replicates g2 protein synthesis, preparation for mitosis influences on the cell cycle cellular division rates complete cell cycle 1224 hours mitosis 1 hour growth factors cytokines pdgf ct and neuroglial cells egf. Cell injury is the process through which a cell is damaged and start to behave in a different manner, in some cases with negative influence to the rest of the cells and organs. This chapter will present an overview of how the pathologist views mechanisms of irreversible cell injury cell death, reversible cell injury, and the organisms.
Also the effects of 24 hrs of blood reflow following the same ischemia periods were determined. Adaptation and reversible injury patterns of tissue. Within limits, the cell can compensate for these derangements and, if the injurious stimulus abates, will return to normalcy. Cell injury it is change in cells morphology and function in response to stress. Studies on the pathogenesis of ischemic cell injury. Mcd cell pathology alexandra burkesmith 5 pulmonary embolism is the most important potential complication arterial thrombosis almost always related to vessel wall injury caused by atherosclerotic plaques. Pathogenesis of human systemic lupus erythematosus. Cells are injured by numerous and diverse causes etiologic agents from intrinsic and. In certain cases the chemical is directly toxic to cellular components such as the plasma membrane or mitochondria, precipitating basic biochemical causes of cell injury see. Contrast ischemia in skeletal muscle tolerates 2 hours versus cardiac muscle tolerate 20. 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. Narrowing stenosis of the artery by thrombus causes ischaemia of the tissue supplied by the artery. Consequences of injury depend on type, state and adaptability of the injured cell.
May 20, 2016 this presentation helps you in understanding the basic concepts of cell injury. At the cellular level, there are many processes that can lead to necrosis. Cell response to injury is not an allornothing phenomenon. Mechanisms of cell injury by activated oxygen species. Reversible cell injury has two morphologic hallmarks cell swelling and fatty change. Morphology of cell injury the first effect of all injuries is on the biochemical and molecular level functional derangement happens next ultrastructural changes seen by electron microscopy follow. 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. The major characteristics of cell injury are atp depletion loss of mitochondrial atp and decreased atp synthesis which results in cellular swelling, decreased protein synthesis, decreased membrane transport and lipogenesis.
Classification of morphologic forms of cell injury. Cell injury may be reversible sublethal or irreversible lethal. Insults due to endogenous or exogenous chemicals free radical cell injury. Oct 26, 2016 a series of video tutorials discussing the pathology of cell injury and adaptations. Cell injury, cell death, and adaptations new age medical.
Appears whenever cells are incapable of maintaining ionic and fluid homeostasis. Etiology of cell injury free download as powerpoint presentation. Most injurious stimuli can be grouped into the following broad categories. Classification of morphologic forms of cell injury mechanism of cell injury 1. Insults due to free radicals generated by reactive oxygen species immune cell injury. The causes of cell injury are classified as exogenous or endogenous. The pathways and identification of cell injury and cell death are of key importance to the practice of diagnostic and research toxicologic pathology. The study of cell injury and cell death is the basis for the understanding of disease mechanisms.
Pathophysiology ch 01 introduction, cell injury, adaptaion. Caused usually by ischemia, occurs in most organs except brain. Cell injury often starts with atp depletion this can happen with several types of injury, including hypoxic injury and chemical injury. Cell injury, adaptation and death mit opencourseware. Following a lethal injury, cellular reactions are initially reversible. Chronic hepatitis typically has a component of fatty change. Although tbi induces changes in multiple cell types, mechanisms of neuronal cell death have been the predominant focus. Two phenomena haveconsistently characterized irre versibly in contrast to reversibly injured ischemic cells. The apoptotic cells are enlarged, pink from loss of cytoplasmic detail, and without nuclei. Overall cell outline maintained after cell death ghost town. Extremely important common cause of cell injury cell death. 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. Jun 11, 2015 this topic covers the mechanism of irreversible cell injury.
Cellular injury is the process through which the cell is unable to maintain its homeostasis in the encounter with injurious stimuli. If you continue browsing the site, you agree to the use of cookies on this website. This type of cell death is characterized by rapid enzymatic degradation of cells into a liquid form. 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. Understanding the characteristics and mechanisms of cell injury and cell death has been the major influence of our laboratory for a number of years. Introduction to pathology cell injury dr heyam awad md, frcpath, jordanian board lecture 4. Mechanisms and morphology of cellular injury, adaptation, and death. It is interesting and essential material for medical practice and medical science. A 48yearold woman has a malignant lymphoma involving lymph nodes in the paraaortic region. The maximal changes occurring after ischemic periods of up to 60 min included. Characteristics and mechanisms of cell injury and cell. When cell death occurs in the living body, the term necrosis is used.
Infections, most often viral hepatitis, may also induce fatty change. Identify the three major mechanisms of cell injury and their. General mechanism of cell injury flashcards quizlet. Cellular injury during cardiac arrest is principally mediated by oxygen deprivation, but additional neurologic injury is incurred depending on associated factors such as concomitant toxic exposures such as carbon monoxide, metabolic stressors such as hypoglycemia, and freeradical production after. However, severe cellular injury leads to irreversible change and death of the affected cells. Mechanical trauma, extremes of temperature burns and deep cold, sudden changes in atmospheric pressure, radiation, and electric. Leakage of cellular content causes inflammation which aims at getting rid f the dead necrotic tissue. Edema most cell types hypereosinophilia coagulation aggregation of proteins dissolution of ribosomes, loss of rna normal corneal epithelium reversible cell injury irreversible cell injury extensive loss of membrane integrity basis of lab tests for heart attack ldh, creatine kinasemb, troponin fatty change liver, heart normal liver. Strayer emanuel rubin p athology is basically the study of structural and functional abnormalities that are expressed as diseases of organs and systems.
Inhibition of macromolecular synthesis dna, rna, protein synthesis 2. Adaptation and reversible injury patterns of tissue necrosis. Necrosis is the type of cell death that is associated with loss of cell membrane integrity and leakage of cellular contents causing dissolution of cells. Just like bones, muscles and skin, your cells too can become injured. Cell damage and necrosis there are many ways of injuring cells in the body, including. Approximately 40 years ago, shalhoub5 proposed a major hypothesis that mcns was caused by a circulating factor derived from dysfunctional t cells. A wide variety of chemicals are can induce severe cellular injury. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Get a printable copy pdf file of the complete article 1. The earliest changes associated with various forms of cell injury are decreased generation of atp, loss of cell membrane integrity, defects in protein synthesis, cytoskeletal damage, and dna damage. First manifestation of almost all forms of cell injury. Cell injury reversible irreversible point of no return. Define and understand the morphologic patterns of lethal cell injury and the clinical settings in which they occur. Cell injury results from different biochemical mechanisms acting on essential cellular components.
Causes include reduced blood flow ischemia, inadequate oxygenation of the blood, decreased blood oxygencarrying capacity. The list of chemicals that may produce cell injury defies compilation. Hypoxia oxygen deprivation is a very important and common cause of cell injury and death. Cell injury occurs when the limits to an adaptive response adaptation have been exceeded or if the cells are not able to adapt. Generally, the cells with mild injury result in reversible cell damage and there is no cellular death. Minor injuries with a long duration can have a more profound effect than a major injury with short duration. If the adaptive capability is exceeded or if the external stress is inherently harmful, cell injury develops fig. Understanding the mechanisms of delayed posttraumatic cell loss may lead to new therapies that improve outcome. Cell injury it is change in cell s morphology and function in response to stress.
Metaplasia a reversible change of one adult cell type for another adult cell type 1. In addition to o2 and h2o2, the third essential component of the complex that mediates the lethal cell injury is a cellular source of ferric iron. Oxygen deprivation to tissue ischemia leading to a form of tissue damage termed an infarct is of notable clinical significance e. These refer to insults due to hereditary defects in key cellular proteins. Currently, we recognize two patterns, oncosis and apoptosis. The role of calcium in cell injury has been the subject of much recent investigation. 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. Discriminate cell adaptation, reversible cell injury and irreversible cell injury cell death based on etiology, pathogenesis and histological and ultrastructural appearance. Mitochondria are important targets for all types of injury, including hypoxia and toxins. General pathology overview of cell injury and cell death.
This hypothesis was based on several findings, such as the presence of no immune complexes in glomeruli, a good response to steroids, and frequent remission. Reversible injury may require cellular adaptation but the cell survives. Microbial insult can occur via direct release of cellular toxins or intracellular infection. Cell death mechanisms and modulation in traumatic brain injury. Haschek and rousseauxs handbook of toxicologic pathology third edition, 20. Cell blebs,a cell surface deformity most likely caused by disorderly function of the cellular cytoskeleton d. The pathogenesis of irreversible cell injur in ischemia europe pmc. The point of no returnis marked by irreversible damage to cell membranes,leading to massive calcium influx, extensive calcification of the mitochondria,and cell. A series of video tutorials discussing the pathology of cell injury and adaptations. The pars recta of the proximal tubule of the rat kidney was examined by means of light and electron microscopy after 15, 30, 60 and 120 min of ischemia produced by clamping of the aorta. Alteration of cell membranes, including the formation of multinucleated giant cells virus induced membrane fusion of infected cells 50100 may fuse together. Oct 12, 2010 cell injury i cell injury and cell death dept. Introduction cell injury is defined as a variety of stresses a cell encounters as a result of changes in its internal and external environment. Current evidence suggests that o2 and h2o2 injure cells as a result of the generation of a more potent oxidizing species.
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