All are true regarding apoptosis except:
Correct Answer: Associated with inflammation
Description: Ref: Robbins Pathologic Basis of Disease, 8th edition, Chapter l, Pg: 3Explanation: ApoptosisApoptosis is a pathway of cell death that is induced by a tightly regulated suicide program in which cells destined to die activate enzymes that degrade the cells' own nuclear DMA and nuclear and cytoplasmic proteins.Apoptotic cells break up into fragments, called apoptotic bodies, which contain portions of the cytoplasm and nucleus.The plasma membrane of the apoptotic cell and bodies remains intact, but its structure is altered in such a way that these become ''tasty" targets for phagocytes.The dead cell and its fragments are rapidly devoured, before the contents have leaked out. and therefore cell death by this pathway does not elicit an inflammatory reaction in the host.Apoptosis is different from NecrosisCharacteristics of NecrosisLoss of membrane integrityEnzymatic digestion of cellsLeakage of cellular contentsInflammatory reactionHowever, apoptosis and necrosis sometimes coexist, and apoptosis induced by some pathologic stimuli may progress to necrosis.Morphology of ApoptosisThe following morphologic features, some best seen with the electron microscope, characterize cells undergoing apoptosisCell shrinkage. The cell is smaller in size; the cytoplasm is dense; and the organelles, though relatively normal, are more tightly packed.Chromatin condensation. This is the most characteristic feature of apoptosis. The chromatin aggregates peripherally, under the nuclear membrane, into dense masses of various shapes and sizes. The nucleus itself may break up, producing two or more fragments.Formation of cytoplasmic blebs and apoptotic bodies. The apoptotic cell first show s extensive surface blebbing. then undergoes fragmentation into membrane-bound apoptotic bodies composed of cytoplasm and tightly packed organelles, with or without nuclear fragments.Phagocytosis of apoptotic cells or cell bodies, usually hv macrophages. The apoptotic bodies are rapidly ingested by phagocytes and degraded by the phagocyte's lysosomal enzymes.Plasma membranes are thought to remain intact during apoptosis, until the last stages, when they become permeable to normally retained solutes.On histologic examination, in tissues stained with hematoxylin and eosin, the apoptotic cell appears as a round or oval mass of intensely eosinophilic cytoplasm with fragments of dense nuclear chromatin.Because the cell shrinkage and formation of apoptotic bodies are rapid and the pieces are quickly phagocytosed, considerable apoptosis may occur in tissues before it becomes apparent in histologic sections.Apoptosis--(in contrast to necrosis)--does not elicit inflammation, making it more difficult to detect histologically.Two pathways for Apoptosis- Mitochondria] (Intrinsic Pathway)- Death receptor (Extrinsic Pathway)
Category:
Pathology
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