Reversible cell injury I Pathology

This presentation is for those who want to understand the basics of reversible cell injury.

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Harshit Jadav I Medical Wala

1. Reversible Cell Injury By Harshit Jadav

2. Cell Injury Ischemia and hypoxia are the most common forms of cell injury Ischemia is insufficient blood flow to provide adequate oxygenation. This, in turn, leads to tissue  hypoxia  (reduced oxygen) Ischemia always results in hypoxia; however, hypoxia can occur without ischemia

3. Normal cell (Homeostasis) Adaptation Cell Injury Irreversible Cell Injury Reversible Cell Injury Necrosis Apoptosis Stress removed Stress Inability to Adapt Severe Progressive Mild Transient Cell Death

4. Reversible Cell Injury If the ischemia or hypoxia is of short duration, the effects may be reversible on rapid restoration of circulation e.g. in coronary artery occlusion, myocardial contractility 1. Decreased generation of cellular ATP 2. Intracellular lactic acidosis: Nuclear clumping 3. Damage to plasma membrane pumps 4. Reduced protein synthesis

5. 1. Decreased generation of cellular ATP Living cells require continuous supply of oxygen to produce ATP Ischemia and Hypoxia causing decreased ATP generation In ischemia , aerobic respiration as well as glucose availability both are compromised resulting in more severe and faster effects of cell injury It also causes accumulation of metabolic waste products in the cells in hypoxia from other causes (RBC disorders, heart disease, lung disease), anaerobic glycolytic ATP generation continues , and thus cell injury is less severe.

6. 2. Intracellular lactic acidosis: Nuclear clumping Due to low oxygen supply to the cell, mitochondria fails first Anaerobic glycolytic pathway activates and generates ATP This results in rapid depletion of glycogen and accumulation of lactic acid Which lowers the intracellular pH. fall in intracellular pH (i.e. intracellular lactic acidosis) results in clumping of nuclear chromatin

7. 3. Damage to plasma membrane pumps Lack of ATP interferes in generation of phospholipids which are required for continuous repair of membranes. Which results in damage to membrane pumps operating for regulation of sodium and calcium 1. Failure of sodium-potassium pump: This pump allows active transport of sodium out of the cell and diffusion of potassium into the cell. Lowered ATP in the cell interfere with this membrane-regulated process. This results in intracellular accumulation of sodium and diffusion of potassium out of cell. accumulation of sodium in the cell leads to increase in intracellular water to maintain isosmotic conditions which is known as hydropic swelling occurs

8. 2. Failure of calcium pump: Membrane damage causes disturbance in the calcium ion exchange across the cell Membrane Excess of calcium moves into the cell (i.e. calcium influx), particularly in the mitochondria causing its swelling and deposition of phospholipid-rich amorphous densities damage is seen in the form of loss of microvilli, intramembranous particles and focal projections of the cytoplasm (blebs). 3. Damage to plasma membrane pumps

9. 4. Reduced protein synthesis Due to continuous hypoxia, membranes of endoplasmic reticulum and Golgi apparatus swell up Ribosomes are detached from granular endoplasmic reticulum So ribosomes disperse in the cytoplasm and inactivating their function Simultaneously protein synthesis reduced in Golgi apparatus Withdrawal of acute stress that resulted in reversible cell injury can restore the cell to normal state

10. 4. Reduced protein synthesis Due to continuous hypoxia, membranes of endoplasmic reticulum and Golgi apparatus swell up Ribosomes are detached from granular endoplasmic reticulum So ribosomes disperse in the cytoplasm and inactivating their function Simultaneously protein synthesis reduced in Golgi apparatus Withdrawal of acute stress that resulted in reversible cell injury can restore the cell to normal state

11. 4. Reduced protein synthesis Due to continuous hypoxia, membranes of endoplasmic reticulum and Golgi apparatus swell up Ribosomes are detached from granular endoplasmic reticulum So ribosomes disperse in the cytoplasm and inactivating their function Simultaneously protein synthesis reduced in Golgi apparatus Withdrawal of acute stress that resulted in reversible cell injury can restore the cell to normal state

12. Today’s Question What is the difference between Disease, Disorder and Syndrome? Give examples with justification. Please give answers in Comment section. (not in WhatsApp/Instagram) See you than… Enjoy … Like, share and Subscribe…