All are cellular adaptations except -
Ans. is 'c' i.e., Necrosis Cellular adaptationo The normal cells is confined to a fairly narrow range of structure and function by its genetic programs of metabolism, differentiation & specilization; by constraints of neighboring cells; and by availability of metabolic substrates,o However, The normal cell is able to handle normal physiological stress to maintain a steady state called homeostasis.o More severe physiological stresses or some pathological stimuli may bring about a number of physiologic and morphologic cellular adaptation, during which new but altered steady states are achieved, preserving the viability of the cell and modulating its function as it responds to such stimuli.o An adapted cell is neither normal nor injured, but has an altered steady state and preserves the viability of the cells in order to escape and protect itself from injury.o The adaptive response may beHypertrophyHyperplasiaAtrophyMetaplasiao If the limits of adaptive response to a stimulation are exceded or if the cell is exposed to an injurious stimulus, cell injury occurs.o Cell injury is reversible up to a certain point, but if the stimulus persists, irreversible injury and ultimate cell death occurs.o There are two principal patterns of cell deathNecrosisApoptosisAtrophyHypertrophyHyperplasiaMetaplasiaDysplasiao Reduced size of an organ or tissue resulting from a decrease in cell size and numbero Caused by ischemia, ageing, malnutrition etc.o May result due to chronic absence of stimulus (disuse strophy)o Increase in size and function of cellso Results due to increase in growth factors or trophic stimulio Includes puberty, Lactating breasts and skeletal muscle fibres (in body builders)o Increase in number of cells intissues/organo Results due to increase in growth factors, increased expression of growth promoting genes and increased DNA synthesis o It persists so long as the stimulus is presento e.g., breast development at puberty, endometrial hyperplasia, benign hyperplasia of prostate, hyperplasia of liver cells after partial hepatectomyo Reversible change in which one differentiated cell type (epithelial or mesenchyma) is replaced by another cell typeo Results from "repro gramming" of stem cells that are known to exist in normal tissues, or of undiff- erentiated mesenchy- mal cells in connective tissue.o Abnormal multi-cation of cells characterized by change in size, Shape and loss of cellular OrganizationoThe basement membrane is IntactoCan progress to cancer
Hypertrophy
Hyperplasia
Necrosis
Metaplasia
Cellular Responses and Adaptations to Stress