Bhanu prakash usmle, fmge and neet pg 12,907 views 5. Pathology cell injury and death flashcards quizlet. Key difference reversible vs irreversible cell injury cells are the main functional and structural units of living organisms. What is the difference between reversible and irreversible. Cell shrinkage, apoptotic bodies which are eaten by macrophages. Define and understand the morphologic patterns of lethal cell injury and the clinical settings in which they occur. Both reversible and irreversible cell injuries occur when stress acts upon cells. Morphology of irreversible cell injury irreversible cell injury necrosis. 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. Cell injury, cell death, and adaptations new age medical. In this tutorial, i have discussed morphology of reversible and reversible cell injury follow me. Cell injury occurs when the limits to an adaptive response adaptation have been exceeded or if the cells are not able to adapt. Within certain limits injury is reversible, and cells return to a stable baseline. Cell injury may be reversible sublethal or irreversible lethal.
Discriminate cell adaptation, reversible cell injury and irreversible cell injury cell death based on etiology, pathogenesis and histological and ultrastructural appearance. 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. Describe the morphology of fatty change that occurs in the liver after reversible cell injury. Cell injury is classified as reversible if the injured cell can regain homeostasis and return to a morphologically and functionally normal state. Causes include reduced blood flow ischemia, inadequate oxygenation of the blood, decreased blood oxygencarrying capacity.
Difference between reversible and irreversible cell injury. If the injurious stimulus is not removed after a long period of time, for example in chronic viral infections, chemical exposures, or an internal response that is. Morphology of reversible cell injury general pathology animated lecture dr bhanu prakash duration. Reversible cell injury pdf the syllabus for cell injury and cell death covers the material to be presented at the. Cell injury it is change in cells morphology and function in response to stress. Pdf mechanisms of cell injury and death researchgate. When cell death occurs in the living body, the term necrosis is used. The irreversible increase in physical attributes of. 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. Contrast ischemia in skeletal muscle tolerates 2 hours versus cardiac muscle tolerate 20. This topic covers the mechanism of irreversible cell injury. Remember, dnases are activated in irreversible cell injury.
Study 5 morphology of reversible cell injury flashcards from lisence a. Cell injury, adaptation and death mit opencourseware. Amongst other causes, this can be due to physical, chemical, infectious, biological, nutritional or immunological factors. Irreversible cell injury is injury to a cell that also causes morphological changes to the cell, albeit more permanent and often, more internal to the inner machinery of the cell. Necrosis is defined as a localised area of death of tissue followed by degradation of tissue by hydrolytic enzymes liberated from dead cells. Cell swelling due to loss of function of plasma membrane energy dependent ion pumps, small clear vacuoles may be seen within the cytoplasm which are distended and pinched off segments of the erfatty change can occur in hypoxic, toxic, and metabolic injury. They have the ability to resist these different external and internal stress stimuli. Morphology of irreversible cell injury apoptosis necrosis. A series of video tutorials discussing the pathology of cell injury and adaptations. Cells undergo many adaptations in response to different environmental, physiological and chemical stimuli. Both are caused by chemical, physical or biological agents. The pathogenesis of cell injury is discussed in great detail. 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.
Morphological changes follow functional changes o reversible. Firstly, is the abnormal morphology seen in every field to be examined. Mechanism of irreversible cell injury the art of medicine. Because acute cell swelling is a common early response to both reversible and irreversible injury, it is well to think of this morphologic change as a marker of potentially reversible cell injury. Extremely important common cause of cell injurycell death. Irreversible oncocytic injury was characterized by cell swelling, inhomogeneously clumped chromatin in nuclei, dense bodies in mitochondria, andor ruptured plasma membranes. After the initiation of irreversible death, the cell and its organelles start to disintegrate, leading to rupture of the cells. 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. Abnormal morphology of red blood cell when a blood smear is inspected for abnormal morphology, two criteria must be met. Adaptation, reversible injury, and cell deathcan be considered. 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. You are asked to participate in a research project on myocardial infarctions in a rat model. Pdf on aug 1, 1996, j p cobb and others published mechanisms of cell injury and death find, read and cite all the. Most injurious stimuli can be grouped into the following broad categories.
There is dissolution of nuclear dna, which result in loss of affinity of nucleus to nuclear stain. In one common pattern of cell death resulting from lack of oxygen, the necrotic cells show increased eosinophilia i. This dynamic state occurs in tissues such as the bone marrow, skin. The different ways by which irreversible cell injury may occur are many. Chapter 1 cell injury, cell death, and adaptations 9. Necrosis refers to the spectrum of morphological changes that follow cell death, i. This presentation helps you in understanding the basic concepts of cell injury. In this tutorial, i have discussed morphology of reversible. Necrosis is the death of a group of cells occurring in living tissue.
Cells injury is engaged in a process that is reversible or irreversible. If the external stress is exceeded or adaptive capability continues, cell injury develops 1, 2. Acute cell swelling is the classic morphologic change in reversible injury. Irreversible cell injury what are the similarities between reversible and irreversible cell injury. One such example is radiation that causes lipid peroxidation, or the breakdown of lipidbased cellular structures due to. A pathologist notes that a biopsy from the lung of living patients shows the morphologic changes indicative of irreversible injury and cell death. If the injury is too severe irreversible injury, the.
Cells, depending on their reparative or regenerative capacities, may recover. If the adaptive capability is exceeded or if the external stress is inherently harmful, cell injury develops fig. The main difference between reversible and irreversible cell injury is that the reversible cell injury can return to the normal conditions by altering the homeostasis of the cell whereas the irreversible cell injury cannot return to the viable conditions as the cell has passed the point of no return reversible and irreversible cell injury are two types of cell injury that can lead to cell death. 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. It affects the endoplasmic and sarcoplasmic reticular membranes of liver and myocardial cells, respectively, and probably the plasma membranes of both. Tf signs of irreversible cell damage can be detected with light microscopy before cell death has occured. Reversible injury may require cellular adaptation but the cell survives. These changes occur due to nonspecific changes in the dna as a result of dnase activity. Oxygen deprivation to tissue ischemia leading to a form of tissue damage termed an infarct is of notable clinical significance e. In adult tissues, the size of a cell population is determined by the rates of cell differentiation, proliferation, and death by apoptosis. Cell function is lost far before biochemical and subsequently morphological manifestations of injury become. Adaptation and reversible injury patterns of tissue. Secondly, is the morphology pathologic and not artificially induced. These features, which are those of oncosis and classic ischemic injury, were already seen in the 0 and 30minute reperfusion groups without tunelpositive myocytes.
Morphology of irreversible cell injury apoptosis necrosis free 30. Cell injury may be reversible nonlethal damage which generally can be. The pathogenesis of irreversible cell injur in ischemia europe pmc. Classes of cell injury reversible if stressor removed, and if cell damage mild. Which of the following is most likely responsible for cell death in a living body. Mechanical trauma, extremes of temperature burns and deep cold, sudden changes in atmospheric pressure, radiation, and electric. It is an intracytoplasmic accumulation of water due to incapacity of the cells to maintain the ionic and fluid homeostasis.
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