Practice question

Stem cells actively participate in tissue development, continuous renewal, repair after injury, and homeostatic maintenance through balanced self-renewal and differentiation, secreting trophic and immunomodulatory factors that modulate niche environment and immune response. Apoptosis is programmed cell death executed by intrinsic and extrinsic caspase cascade leading to orderly elimination of damaged, redundant, or infected cells, characterized by membrane blebbing, chromatin condensation, DNA fragmentation, and phagocytic clearance without inflammation. It is not a constructive synthetic function of stem cells but rather a quality control mechanism sometimes activated in stem cells themselves to prevent propagation of potentially oncogenic mutations.