General mechanism of cell injury flashcards quizlet. Cell death occurs when the severity of the injury exceeds the cells ability to repair itself. Cellular function is lost far before cell death occurs, and the morphologic changes of cell injury or death lag far behind both. Extremely important common cause of cell injurycell death. Within certain limits injury is reversible, and cells return to a stable baseline. Depending on the extent of injury, the cellular response may be adaptive and where possible, homeostasis is restored.
Therefore, although an injurious agent may target a particular aspect of cell structure or function, this will rapidly lead to wideranging secondary effects. Mechanisms of cell injury the structure and metabolic functions of the cell are interdependent. Cell injury may be reversible sublethal or irreversible lethal. P athophysiology, concussion, mild traumatic brain inj ury, traumatic b. Thrombosis, artherosclerosis diminished o2 carrying capacity of blood, eg. 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. There are four structures within a cell that are particularly vulnerable to injury. Cell injury, adaptation and death mit opencourseware. Cell injury occurs when the limits to an adaptive response. The cellular organelles that play major role in these processes are mitochondria and lysosomes. This presentation helps you in understanding the basic concepts of cell injury. Cell death is valuable for the organism because it removes terminally injured or unwanted cells that utilize valuable substrates and nutrients. Tutorial contains images and text for pathology education.
Cell function is lost far before biochemical and subsequently morphological manifestations of injury become detectable. Aug 27, 2012 there are four structures within a cell that are particularly vulnerable to injury. Mechanism of irreversible cell injury the art of medicine. The causes of cell injury are classified as exogenous or endogenous. Adaptation and reversible injury patterns of tissue. Causes include reduced blood flow ischemia, inadequate oxygenation of the blood, decreased blood oxygencarrying capacity. Cell injury results when cells are stressed and can no longer adapt. In other words, inflammation is a protective response to rid the body of the cause of cell injury and the resultant necrotic cells that cell injury produces. Hyperplasia is primarily operative in which of the following growth alterations a appearance of affected kidney in renovascular hypertension. Inflammation is the bodys normal physiological response to injury. May 15, 2018 in this video we have discussed the different mechanisms of cell injury. 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. Mechanism of cell death in case of ionizing radiation. Mechanism of cell injury learning objectives discuss the mechanisms of cell injury in terms of.
Professor and hod of the department of pathology at. This has big implications for the use of pathology as gold standard for evaluation of new technologies that could detect changes before they are morphologically apparent. Discriminate cell adaptation, reversible cell injury and irreversible cell injury cell death based on etiology, pathogenesis and histological and ultrastructural appearance. Explain ischemic injury,reperfusion injury and toxic injury with the help of selected clinical examples of cell injury and necrosis.
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. In this video we have discussed the different mechanisms of cell injury. Likewise, cell death also has value for the species, as it provides a mechanism for eliminating terminally injured individuals who consume necessary societal resources or harbour toxic pathogens. The cause of tissue injury is attributed to trauma, autoimmune, microbial, heat and toxins chemicals. Define and understand the morphologic patterns of lethal cell injury and the clinical settings in which they occur. Cell injury general mechanisms four very interrelated cell systems are. Mechanisms of endothelial dysfunction, injury, and death. 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. May 20, 2016 this presentation helps you in understanding the basic concepts of cell injury. Cell injury occurs when the limits to an adaptive response adaptation have been exceeded or if the cells are not able to adapt. Co poisoning poisoning of oxidative enzymes, cyanide. However, secondary mechanisms of injury can exacerbate damage and limit restorative processes, and hence.
Reversible injury may require cellular adaptation but the cell survives. Studies of cellular responses in vivo indicate that. Dna or proteins are damaged beyond repair, the cell kills itself characterized by nuclear dissolution, fragmentation of the cell without complete loss of membrane integrity. Mechanisms of cell injury and death 5 figure 1 electron micrographs of murine thymocytes from normal a, sham laparotomy and septic b, caecal ligation and puncture mice. Likewise, cell death also has value for the species, as it provides a mechanism for eliminating terminally injured. Chapter 1 cell injury, cell death, and adaptations 19. Full text get a printable copy pdf file of the complete article 2. Mechanism of cellular injury there is increased rate of anaerobic glycolysis depletion of glycogen stores, and accumulation of.
Normal cell destruction followed by replacement proliferation such as in intestinal epithelium. Homeostasis is the normal steady dynamic cell state. The causes of cell injury, reversible or irreversible, may be broadly classified into two large groups. Mechanical trauma, extremes of temperature burns and deep cold, sudden changes in atmospheric pressure, radiation, and electric shock. Although the processes of acute and chronic inflammation are an important protective mechanism used by the.
Pathology mechanism of cell injury mechanism of cell. This chapter will present an overview of how the pathologist views mechanisms of irreversible cell injury cell death, reversible cell injury, and the organisms. In this case, it is an orderly process and part of normal. 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. Dna damage that is irreparable results in apoptosis apoptosis can also result in misfolded proteins. Oxygen deprivation to tissue ischemia leading to a form of tissue damage termed an infarct is of notable clinical significance e.
Cell injury, cell death, and adaptations examples of cell injury and necrosis ischemic and hypoxic injury ischemiareperfusion injury chemical toxic injury apoptosis causes of apoptosis mechanisms of apoptosis examples of apoptosis intracellular accumulations pathologic calci. Pathology of cell injury for medical education webpath. Mar 19, 2020 a pathologist notes that a biopsy from the lung of living patients shows the morphologic changes indicative of irreversible injury and cell death. Terms in this set 29 what is the most common immediate cause of cell injury and what are the mechanisms. Most injurious stimuli can be grouped into the following broad categories. Introduction cell injury is defined as a variety of stresses a cell encounters as a result of changes in its internal and external environment. P athophysiology, concussion, mild traumatic brain inj ury, traumatic b rain injury, kenya, neural structures. We rarely use electron microscopy in diagnostic pathology, but we often examine cells.
This has big implications for the use of pathology as gold standard for evaluation of new technologies that could detect changes. 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. Sep 21, 2017 reversible cell injury results in morphological and cellular changes that could be reversed if the stress is taken off. Injury or cell death impairs or prevents conduct of these activities, resulting in dysfunction. Physiologic involution of cells in hormone dependent tissues endometrial shedding during mensuration endometrial shedding during mensuration regression of lactating breast after withdrawal of breastfeeding. What is the major final common pathway for cellular injury and what is the mechanism. Jun 11, 2015 this topic covers the mechanism of irreversible cell injury. Pathologic cell injury and cell death i mechanism of. Inflammation is the bodys mechanism for coping with agents that could damage it. Cell death mechanisms following traumatic brain injury.
This is the mechanism in immune injury and when viralloaded cells are destroyed by the body. 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. Chemicals induce cell injury by one of two general mechanisms. Recent advances in cellular biology have contributed substantially to our understanding of the processes of cell injury and death, and have provided. Fundamentals of toxicologic pathology sciencedirect. 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 it is change in cell s morphology and function in response to stress.
The pathogenesis of cell injury is discussed in great detail. Role of free radicals in disease causation and antioxidants in their prevention. Depending on the cell type, oxidative dna damage can be coupled to cell killing through a mechanism related to the activation of poly adpribose polymerase. Spinal cord injury may be divided into both primary and secondary mechanisms of injury. If the adaptive capability is exceeded or if the external stress is inherently harmful, cell injury develops fig. Within limits, the cell can compensate for these derangements and, if the injurious stimulus abates, will return to normalcy. Haschek and rousseauxs handbook of toxicologic pathology third edition, 20. Neuronal and glial cell death and traumatic axonal injury contribute to the overall pathology of traumatic brain injury tbi in both humans and animals. The cellular organelles that play major role in these processes are. When cell death occurs in the living body, the term necrosis is used. At the cellular level, there are many processes that can lead to necrosis. We make appropriate adjustments, so does the cell the unit of life.
The primary injury, in large part, determines a given patients neurologic grade on admission and thereby is the strongest prognostic indicator. Cell injury and cell death taiwanese pathology site. Light microscopy of cell injury the electron microscopic appearances of hurt cells described in big robbins reiterate the mechanisms of cell injury. From this perspective, pathology is the study of cell injury and the expression of a cells preexisting capacity to adapt to such injury. Difference between reversible and irreversible cell injury. Vascular endothelial cells normally perform several key homeostatic functions such as keeping blood fluid, regulating blood flow, regulating macromolecule and fluid exchange with the tissues, preventing leukocyte activation, and aiding in immune surveillance for pathogens. I will discuss histological changes in cells, cellular swelling and steatosis. Cell injury it is change in cells morphology and function in response to stress. Mechanisms of cell injury by activated oxygen species. Which of the following is most likely responsible for cell death in a living body.
You are asked to participate in a research project on myocardial infarctions in a rat model. As you learned in the immune system module, there is an intimate relationship between the mechanism of inflammation and the immune system response. The vascular response to injury is a dynamic event that involves sequential physiological and pathological changes. General principles cell response to injury is not an allornothing phenomenon response to a given stimulus depends on the type, status, and genetic makeup of the injured cell cells are complex interconnected systems, and single local injuries can result in multiple secondary and tertiary effects cell function is lost far before biochemical and. Cell death is relative to both the length of exposure to a harmful stimulus and the severity of the damage caused. Reversible cell injury has two morphologic hallmarks cell swelling and fatty change. Sep 22, 2009 cell injury may be reversible or irreversible 6. Reversible cell injury results in morphological and cellular changes that could be reversed if the stress is taken off. 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. Control of the rate of cell death relative to the rate of cell division maintains organ integrity and physiological homeostasis. 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. Such an orientation leaves little room for the concept of parallelnormal and pathologicbiologies. 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.
Reactions to persistent stress and cell injury persistent stress often leads to chronic cell injury. Cell injury, cell death, and adaptations new age medical. Fundamentals of toxicologic pathology second edition updates the information presented in the first edition, including five entirely new chapters addressing basic concepts in toxicologic pathology, along with color photomicrographs that show examples of specific toxicantinduced diseases in animals. Pdf mechanisms of cell injury and death researchgate.
Cell injury is any disruption, physical or chemical, that results in the loss of a cells or tissues ability to maintain homeostasis, in either a normal or adapted state. Cell injury often starts with atp depletion this can happen with several types of injury, including hypoxic injury and chemical injury. Full text get a printable copy pdf file of the complete article 1. Unit 2a hand injury prevention hand injury prevention quiz questions. This is the key difference between reversible and irreversible cell injury. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
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