Apoptosis: Programmed Cell Death
Apoptosis is valid for most of our cells except the Cancer cells.
As we know the life span of RBC is 120 days , after their turn is over they need to be destroyed. The worn our RBC's are destroyed in spleen and obey Apoptosis.
Same phenomenon goes with other cells of our bodies like platelets , old wbc's etc.
Apoptosis or Programmed cell death is a natural phenomenon through which our body cells are killed after their life span is over.
But in case of cancer cells , apoptosis becomes non fucntional , so they just dont die and keep on dividing and forms bunch of cells , we call it tumor.
Programmed cell death
Cells either die via necrosis or apoptosis. Apoptosis is programmed (to maintain normalcy within an organism), whereas necrosis is due to external factors such as injury or poison.
Apoptosis is controlled so that unneeded or potentially dangerous cells are eliminated. During apoptosis, the cell commits suicide. The organelles, DNA, and eventually the entire cell splits into small fragments. These parts are devoured by the phagocytes/macrophages.
Apoptosis is critical to maintaining homeostasis (internal stability) and getting rid of cancerous cells. Unlike necrosis, it is beneficial.