Apoptosis vs Necrosis

 Leaves are falling off the tree.

Apoptosis

 1. Apoptosis is a special type of cell death mechanism in which the pre-program cell death mechanism is triggered and cell undergoes suicidal death process.

 2. Cell size get shrinkage.

 3. Plasma membrane intact; altered structure, specially orientation of lipids.

 4. Cellular content: intact; may be released in Apoptotic bodies.

 5. Often physiologic

 6. No inflammatory reaction

Necrosis

 1. Necrosis is a pathologic process that is a consequence of severe injury.

 2. Cell get enlarged.

 3. Plasma membrane disrupted.

 4. Cellular contents: enzymatic digestion; may leak out of sale.

 5. Usually pathologic.

 6. Causes inflammatory reaction

Apoptosis in physiologic situation:

 1. Removal of supernumerary cell during embryogenesis.

 2. Hormonal withdrawal.

 Eg:- endometrial cell breakdown during the menstrual cycle, regression of the lactating breast after weaning.

 3. Cell turnover in proliferating cell population. Eg- epithelial cell in intestinal crypts, to maintain a constant cell number (homeostasis)

 4. Illumination of potentially harmful self reactive lymphocytes.

Actresses in pathologic condition

(apoptosis eliminates cells that are injured beyond repair)

 1. DNA damage : radiation and cytotoxic anticancer drugs can damage DNA.

 2. Accumulation of misfolded protein

 3. Pathologic atrophy in parenchymal organ after duct obstruction

 Eg- such as occurs in the pancreas, parotid gland and kidney.