Cellular Adaptations in Biology

Cellular Adaptations

• Cellular adaptations are changes cells undergo in response to environmental stimuli.
• Major types include hypertrophy, atrophy, hyperplasia, metaplasia.
• Hypertrophy: Increase in cell size.
  • This is driven by increased workload.
  • Leads to increased protein synthesis and intracellular organelle size.
  • Resulting increased cell size causes increased organ size.
  • Examples include enlarged left ventricle (hypertensive heart disease) and skeletal muscle growth with exercise.
• Atrophy: Decrease in cell size.
  • Can be caused by factors like disuse, undernutrition, decreased endocrine stimulation, denervation, or old age.
  • Associated with muscle cell loss in inactivity and aging.
  • Causes a decrease in organ size.
• Hyperplasia: Increase in cell number.
  • Often linked to hormonal stimulation or increased workload.
  • Results in increased organ size.
  • Examples include breast enlargement during pregnancy and endometrial hyperplasia.
• Metaplasia: Replacement of one differentiated cell type with another.
  • Columnar epithelium can transition to squamous epithelium in smokers' lungs.
  • Connective tissue can turn into bone at injury sites.
  • Illustrates cells' adaptability to changing conditions.
• Dysplasia: Abnormal changes in cell size, shape, and organization.
  • Though not cancer, it can develop into cancer.
  • Severity varies (mild, moderate, severe), based on microscope findings.
  • Impacts tissue and organ in affected areas.