Apoptosis is a pathway of cellular suicide. Occurs without an inflammatory response. Responsible for programmed cell death in important physiological and pathological processes.
Programmed death of the cells in embryogenesis
Hormone dependent physiological involution
Cell deletion in proliferating populations
Irreparable DNA damage
Apoptosis can be triggered by internal and external stimuli.
Internal - p53 activation
Internal embryogenic signals
External – Release of granzyme B by cytotoxic T cells.
Specific ligand receptor interaction
The conversion of these signals to death signal is done by the execution of the caspases. BCL-2 class proteins of the mitochondria regulate the process of apoptosis.
After the execution DNA is fragmented into nucleosome size pieces. Cytoskeleton is broken down and finally karyorrhexis occurs.