Apoptosis

Apoptosis is the pathway of genetically intra cellular programmed cell death (cell suicide) in which unwanted host cells are eliminated by activation of intrinsic enzymes that degrade cell’s own DNA, Nuclear & cytoplasmic proteins

* Apoptosis always present physiologic & pathological condition.

*absence of survival factor /Absence of getting signal to cell; so cell size is decrease and containing apoptic bodies.

*In apoptosis no inflammation is present.

Apoptosis always present in pathological & physiological situations.

Apoptosis in physiologic situation

· During embryo which includes implantation, organogenesis, metamorphosis etc. during all these stage of development ;lots of cells are known unneeded, and they die via apoptosis in programmed manner.

 2)Harmone- dependent apoptosis tissue:- Eg- When mother stopped breast feeding to her child.then lactin harmone reduces the breast size and return back to their normal previous size that occur by apoptosis.

Apoptosis is the very common phenomena in multicellular organism. When the number of cell is very high then apoptosis occuring and reducing the no. of cells and maintain it.

Eg- replacement proliferation such as in intestinal epithelium

4) Elimination of blood cells after they have performed their role during their life span.

5) loss of immature B& T cells in the bone marrow and thymus by clonal deletion & cytotoxicity

Apoptosis in pathologic situation

Eg- Chemotherapy in treatment of cancer irradiation by therpy performed mild thermal injury or Hypoxia.

It’s due to accumulation of large excess of misfolded pattern formed by free redical injury or from mutations

Exp- council man bodies in viral hepatitis,

Progressive depletion of CD4 + T cells in HIV infection.

Cell death by cytotoxic T cell in transplant refection reaction