Morphology of cell injury-adaptive changes Atrophy,hypertropy, hyperplasia, Metaplasia, Dysplasia

Adaptation is defined as reversible change in size number phenotype metabolic activity of function in response to change in external and internal environment.

Adaptation may be due to physiological change, pathological change physiological adaptation is due to hormonal change or may be induced by endogenous chemical used

Various adaptive response of the cell are as follows.

  • Hypertrophy: Increase in nourishment
  • Hyperplasia: Increase in growth
  • Metaplasia: Transfer
  • Dysplasia: Disorganised
  • Hypertrophy : increase in cell size without increase cell number.
  • Hyperplasia: increase in cell number without increase cell size.
  1. Hypertrophy: it is increase in cell size without increase in cell number leading to enlargement of an organ. Ex: hypertrophy of left ventricular muscle in response to Hypertension.
  2. Hyperplasia: It is increase in cell number without increase in cell size. Hyperplasia occurs in labili and stable cells which are capable of cell division. Ex: hyperplasia which is seen when an organ or a part of organ removed (enlargement of liver after removal of part of liver.)
  3. Metaplasia: it is reversible change it is seen in epithelial or mesenchymal tissue where one type of epithelial tissue or mesenchymal tissue is change to another type of epithelial or mesenchymal tissue. Ex: Epithelial metaplasia
  4. Dysplasia: Dysplasia is discovered cellular development often seen with metaplasia and a typical hyperlasia. It is characterized by cellular proliferation seen in epithelial tissue due to cellular proliferation there is disorders in arrangements of cell from apex to the facial layer.
  5. Atrophy: (reduction of cell division) Atrophy is the general physiological process of reabsorption and breakdown of tissue involving apoptosis when it occurs as a result of disease or loss of trophic support because of other diseases.

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