Irreversible cell injury

25 %
75 %
Information about Irreversible cell injury

Published on August 8, 2011

Author: suraj_mindgamer



The molecular mechanisms connecting most forms of cell injury to ultimate cell death have proved elusive, for several reasons.

First, there are clearly many ways to injure a cell, not all of them invariably fatal.

Second, the numerous macromolecules, enzymes, and organelles within the cell are so closely interdependent that it is difficult to distinguish a primary injury from secondary (and not necessarily relevant) ripple effects.

Third, the "point of no return," at which irreversible damage has occurred, is still largely undetermined; thus, we have no precise cut-off point to establish cause and effect.

Finally, there is probably no single common final pathway by which cells die. It is, therefore, difficult to define the stage beyond which the cell is irretrievably doomed to destruction.

Classes of Cell Injury Reversible If stressor removed, and If cell damage mild: cells survive Irreversible --> cell death. Types: Apoptosis: normal (leaves falling) as in menses, aging PROGRAMMED Necrosis: patho-logical... Autolysis: after death of entire organism (dissolution of dead cells by its own digestive enzymes)

PROBABLE CAUSES The first is the inability to reverse mitochondrial dysfunction (lack of oxidative phosphorylation and ATPgeneration) even after resolution of the original injury. The second is the development of profound disturbances in membrane function.


NECROSIS DEFINITION: Death of a group of contiguous cells within a living tissue or organ Affect both nucleus and cytoplasm Unregulated cell death with inflammation

Morphological changesDURING NECROSIS CytoplasmicNuclearCytoplasmic changes : Cytoplasmiceosinophilia due to loss of normal basophilia& increased binding of eosin to denaturated proteins (Granular or homogenous glassy)  Nuclear changes: Pyknosis: shrinkage-increased staining with haematoxylin Karyorrhexis: fragmentation Karyolysis: total disappearance



TYPES: NECROSIS Coagulative Liquefactive Caseation Fat

COAGULATIVE NECROSIS In: infarcts of kidney, heart, spleen Gross: pale , yellow, opaque, firm Mic.: All cellular details are lost but general architecture of the tissue is preserved Surrounding tissue----acute inflammation Ex: Infarction - heart  Infarction - kidney        

LIQUEFACTIVE NECROSIS In: centers of pyogenic abscess amoebiasis infarcts of C.N.S. Necrotic tissue---completely liquified---turbid fluid----absorbed----space Ex: Brain - infarction  Amoebiasis ---liver 

CASEATION NECROSIS In: Tuberculosis Necrotic tissue is partially liquefied---cheesy material (caseation) Mic: Both cellular details & general architecture of dead tissue are lost---structurelesseosinophilic material

FAT NECROSIS Traumatic: in female breast Enzymatic: in acute hemorrhagic pancreatitis Gross: opaque & white fat cells appear cloudy, surrounded by chronic inflammatory cells, histiocytes, foreign body giant cells      


APOPTOSIS   (programmed cell death)  Definition:death of individual cells surrounded by viable cells when a cell dies through activation of an internally suicide program It is an active process—energy dependent Does not elicit inflammatory response May be physiologic or pathologic

APOPTOSIS CAUSES PHYSIOLOGIC During embryogenesis e.g. removal of interdigital webs during embryonic development of toes and fingers Hormone-dependent e.g. endometrial cellloss in menstruation PATHOLOGIC Irradiated tissues Cell death induced by cytotoxic T-lymphocytes Viral infections e.g. viral hepatitis Cell death in tumours

Differences between necrosis and apoptosis Necrosis Death of groups of cells A passive process—not energy-dependent Elicits inflammatory response Always pathologic Apoptosis Death of individual cells Active process—energy-dependent Does not elicit inflammatory response May be pathologic or physiologic


FATTY CHANGE  Definition: -abnormal accumulation of triglycerides within parenchymal cells Sites: Liver (the most common) Others, heart, kidney,-- Pathogenesis:  Excessive accumulation of triglycerides within the liver may result from defects in any one of the events in the sequence from fatty acid entry to lipoprotein exit

FATTY CHANGE CAUSES Congestive heart failure Diabetes mellitus Severe anaemia Ischaemia Septicaemia Poisons malnutrition

FATTY CHANGE EFFECTS In all organs, fatty change appears as clear vacuoles within parenchymal cells Due to fat solvents used in paraffin embedding To identify fat, frozen tissue sections are stained with Sudan IV or Oil Red-O---orange-red colour When mild - - - no effects on cell function Severe - - - - - -impair cell function


Add a comment

Related pages

Robbins Chapter 1: Cell Injury & Death - DR. JUDY MELINEK ...

· Irreversible mitochondrial damage: leakage of cytochrome c triggering apoptotic cell death Reversible cell injury: cell swelling, ...
Read more


Read more

Reversible Cell Injury | PharmaTutor

Cell Injury . REVERSIBLE CELL INJURY (RCI): If ischemia or hypoxia is for short period of time, the cell can be reverting back to its normal condition ...
Read more

irreversible cell injury - Med School Notes Archives

General Pathology - Irreversible Cell Injury. Lots of things happening in cell injury situations:- Influx of Ca2+, Na+, loss of K+- Membrane injury ...
Read more

Cell damage - Wikipedia, the free encyclopedia

Cell damage can result in death of individual cells, tissue or organ failure and/or death of the organism. Harmful molecules are continually bombarding the ...
Read more

Irreversible Cell Injury and Necrosis Flashcards

Irreversible Cell Injury and Necrosis. Description. 8.3 at 8:30am by Dr. Vander Heide. Total Cards. 55. Subject. Pathology. Level. Professional. Created ...
Read more

Irreversible Cellular Injury and Death: Types and Causes ...

This lesson will discuss the different causes and types of irreversible cell injury. Notably, we'll focus in on the different types of necrosis...
Read more

Cellular Pathology 2: Reversible and Irreversible Cellular ...

Vocabulary words for Cellular Pathology 2: Reversible and Irreversible Cellular Injury and Necrosis Dr. Costa (PATH). Includes studying games and tools ...
Read more

4-Reversible and Irreversible cell injury flashcards | Quizlet

Vocabulary words for 4-Reversible and Irreversible cell injury. Includes studying games and tools such as flashcards.
Read more