Pathophysiology

Altered Cellular and Tissue Biology

cellular adaptation

• response to conditions

  • physiologic (normal) and pathologic (adverse)

  • maintain homeostasis

  • reversible

• adaptive changes

  • atrophy

    • a decrease in cell size

    • caused by aging, disuse, insufficient blood supply, and insufficient hormonal/neural stimualtion

  • hypertrophy

    • increase in cell size

    • caused by mechanical stimuli, physiologic - increased demand, hormone stimulation, and growth factors, and pathologic - chronic hemodynamic overload

  • hyperplasia

    • an increase in number of cells, increased rate of mitosis (cellular division), physiologic - compensatory hyperplasia, hormonal hyperplasia, and pathologic hormonal hyperplasia

  • metaplasia

    • reversible replacement of mature cell type by another

    • associated with tissue damage, repair, and regeneration

  • dysplasia

    • abnormal changes in size, shape, organization of mature cells, tissue disappears disorderly, but is not cancer

    • not cancer, but:

      • invasive neoplasm if changes penetrate basement membrane

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