Cell death and Necrosis - Types - S.pptx

Cell death and Necrosis - Types - S.pptx

1. Cell death-necrosis Dr. P. Shiny latha M.B.B.S., M.D.,

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3. Programmed cell death Accidental cell death

4. NECROSIS (Gr: Nekrosis = death) Necrosis is a process of  localized cell death      degradation of tissue  by hydrolytic enzymes. the inability of the cells to maintain membrane integrity, leading to the leakage of cellular contents  extensive inflammatory reaction.

5. MECHANISM OF NECROSIS a. Denaturation of intracellular proteins  b. Leakage of cellular contents thru damaged membranes c. Enzymatic digestion of the cell. Denaturation of proteins disrupts their normal function  cellular dysfunction  cell death.

6. DAMP Damage Associated Molecular Patterns Specific substances released from injured cell ATPs – released from damaged mitochondria Uric acid- breakdown product of DNA

7. COAGULATIVE NECROSIS MC type of necrosis sudden cessation of blood supply (ischemia) to an organ or tissue heart, kidneys, and spleen Removed later by phagocytosis Example Myocardial Infarction following occlusion of coronary arteries

8. COAGULATIVE NECROSIS The affected tissue- kidney appears firm, pale, and swollen in the early stages turning softer, yellowish, and shrunken as it progresses.

9. Microscopically,  coagulative necrosis is identified by the preservation of cell outlines but with loss of nuclear detail.

10. 24 Infarcted Heart Normal

11. LIQUEFACTIVE NECROSIS occurs due to ischemic injury to the brain or bacterial/fungal infections  formation of abscesses. the complete digestion of dead cells  liquid, viscous mass. due to the action of hydrolytic enzymes , which is particularly evident in the CNS where the brain tissue turns into a fluid-filled cavity.

12. CASEOUS NECROSIS Characteristic of  tuberculosis infections,  this type of necrosis presents a  cheese-like appearance  of the affected tissue Caseous= cheese Obliterates structure; appears eosinophilic, granular & amorphous

13. CASEOUS NECROSIS Microscopically,  caseous necrosis appears as eosinophilic granular debris Structureless collection of fragmented or lysed cells, typically surrounded by granuloma comprised of  epithelioid histiocytes, lymphocytes,  and  multinucleated giant cells.

14. FAT NECROSIS This type of necrosis specifically affects fat tissue and can occur due to  trauma (such as in the breast)  or  enzymatic action (as in acute pancreatitis).

15. FAT NECROSIS In Traumatic fat necrosis , the fatty tissue is damaged directly In Enzymatic fat necrosis , pancreatic enzymes digest the fat cells  the release of triglycerides and fatty acids. These fatty acids then bind with calcium to form chalky white deposits known as  saponification.

16. FAT NECROSIS In Traumatic fat necrosis , the fatty tissue is damaged directly In Enzymatic fat necrosis , pancreatic enzymes digest the fat cells  the release of triglycerides and fatty acids. SAPONIFICATION

17. 43 Fat Necrosis - Morphology Acute pancreatitis with fat necrosis : chalky white areas (red arrow) are calcium soap (figure left) The necrotic fat cells at the right (black arrow) have vague cellular outlines without nuclei, and cytoplasm has become a pink & amorphous .

18. FIBRINOID NECROSIS Immune reactions involving blood vessels , associated with  immune-mediated conditions vasculitis hypertension-induced vascular damage.

19. FIBRINOID NECROSIS The affected vessels show deposition of fibrin-like material in the wall ,  bright eosinophilic (pink) staining  during histological examination This material is composed of plasma proteins, including fibrin, That material escape from the bloodstream into the vessel wall  thickening  occlusion of the vessel  tissue damage.

20. 47 It is an indication of severe damage to the vessel wall, caused usually by hypertension or immunological process. It is not clear Whether it is truly necrosis or plasma protein insudation

21. 49 Gangrene ( Gr: Gangraina = an eating sore) The term Gangrene is used when necrosis is modified by super-added putrefaction

22. 50 Common Causes of Gangrene Diabetes Mellitus Embolism Senile arteriosclerosis Raynaud disease Ergot poisoning Thromboangitis obliterans Frostbite, crush injury Generally seen in extremities and bowel Gas gangrene is caused by Clostridium welchii, Cl. perfringes, Cl. septicum, Cl. novyi, Cl. histolyticum, Cl. Sporogenes

23. 51 Gangrenous Necrosis  Wet gangrene  Dry gangrene

24. 52

25. 53 Special types of gangrene Ainhum (little toe) Fournier Gangrene (scrotum)  Post-operative synergistic gangrene (Necrotising Fascitis) Cancrum Oris (Noma)

26. Fat necrosis Liquefactive necrosis Fibrinoid necrosis

27. Caseous necrosis Coagulative necrosis