Irrversible Cell Injury

Question 1

What is irreversible cell injury ?

Answer 1

Severe cell injury that the cell can NOT recover after the removal of adverse influence .

Question 2

Necrosis

Answer 2

It is changes that accompany the cell death , generated by degradative action of enzymes released out of lysosomes of the dying cell itself OR the leukocytes (WBCs)

Question 3

The major characteristic of necrosis is :

Answer 3

The cell’ s inability to maintain plasma membrane integrity THEN leakage of intracellular proteins

Question 4

Necrosis detection in MI & hepatitis :

Answer 4

1. Necrotic myocytes release certain isoform of creatine kinase and contractile protein troponin within the circulation
2. Necrotic hepatocytes release alkaline phosphatase and transaminases (GPT and GOT )

Question 5

Necrosis appearance ultrastructurally :

Answer 5

1. Fragmentation of plasma and organelles membrane
2. Myelin figures
3. Lysosomes rupture
4. Nuclear condensation or dissolution
5. ER swelling with the loss of ribosomes
   6.mitochondrial dilatation

Question 6

Necrosis appearance in LM :

Answer 6

1. Increased cytoplasmic eosinophilia ( eosin binds with denatured cytoplasmic proteins )
2. Glassy homogenous appearance ( loss of glycogen particles )
3. Vacuolated cytoplasm ( degradation of organelles )
4. Myelin figures ( replacement of dead cells usually )

Question 7

Necrosis patterns :

Answer 7

1. Coagulative necrosis
2. Liquefactive necrosis
3. Caseous necrosis
4. Fat necrosis
5. Fibrinoid necrosis
6. Gangrene necrosis

Question 8

Coagulative necrosis is characterised by :

Answer 8

Preservation of tissue architecture

Coagulative necrotic cells appear eosinophilic and anucleated ( karyolysis )

Question 9

General mechanism of coagulative necrosis :

Answer 9

• Proteins denaturation and Inhibition of enzyme activity
• leading to blocking of proteolysis of dead cells

Question 10

Coagulative necrosis occur only in :

Answer 10

Solid organs except brain

Question 11

Coagulative necrosis Example :

Answer 11

MI

Question 12

How to determine necrotic myocardial cells :

Answer 12

Acidophilic , loss of nuclei and striations

Question 13

How to get red of coagulatied necrotic cells :

Answer 13

Fragmentation and phagocytosis

Question 14

Liquefaction necrosis is characterised by :

Answer 14

Softening of of the necrotic tissue

Question 15

Liquefaction necrosis is found in :

Answer 15

1. Brain infarction
2. Abscess

Question 16

Liquefaction necrosis in brain is due to :

Answer 16

Hydrolytic action of enzymes

Question 17

The organelles involved in Liquefactive necrosis in abcsess :

Answer 17

Lysosomes of the inflammatory cells invading the necrotic tissue

Question 18

Abscess occurs due to

Answer 18

Pyogenic bacterial or fungal infection producing pus

Question 19

Pus definition

Answer 19

Necrotic tissue with inflammatory cells are transformed into thick yellow creamy material

Question 20

Liquefactive necrosis mechanism

Answer 20

1. Complete digestion of dead cells
2. Transformation into a viscous liquid
3. Loss of the general architecture of tissue

Question 21

How to get rid of Liquefactive necrotic tissue

Answer 21

Phagocytosis

Question 22

Caseous necrosis gross appearance :

Answer 22

• cheesy yellow white necrotic area
• Nicrotic material : soft greasy

Question 23

Caseous necrosis macroscopically

Answer 23

• complete loss of tissue architecture and fragments ( structureless and amorphous granulomas )

Question 24

Caseous necrosis microscopically :

Answer 24

1. Epithelioid cells ( altered macrophages )
2. Granuloma ( whole necrotic lesion )
3. Langerhan’s giant cells ( multi uncleared giant cells )

Question 25

Caseous necrosis found in diseases as :

Answer 25

1. Tuberculous infection 2. Tuberculous lymphadenitis

Question 26

Severe tuberculosis is characterised by :

Answer 26

There are cystic spaces ( cavitation ) in the destructed tissue

Question 27

What is fat necrosis ?

Answer 27

Fat destruction due to release of activated pancreatic lipases

Question 28

Where could fat necrosis be found ?

Answer 28

Fat cells in and around the pancreas , in omentum , and subcutaneous tissue .

Question 29

Cases related to fat necrosis :

Answer 29

1. Acute hepatitis 2.trauma to fat

Question 30

What happens in acute pancreatitis ?

Answer 30

1. Pancreatic enzymes are released out of the acinar cells and ducts that liquefy the membrane of fat cells 2. Lipases split of the triglycerides within the cytoplasm of fat cells 3. Accumulated fatty acids combine with calcium

Question 31

Trauma to fat

Answer 31

In breast and subcutaneous tissue

Question 32

How to detect fat necrosis

Answer 32

Staining of oil red O or Sudan IV H&E stain

Question 33

Fat appearance in Oil red O Or Sudan IV :

Answer 33

Red intercytoplasmic granules

Question 34

H&E stain

Question 35

What is Fibrinoid Necrosis in polyarthritis nodosa :

Answer 35

Antigen- antibody complex combine with fibrin ( that has leaked out of vessels ) then deposit in the wall of arteries involved in immune reaction

Question 36

Fibrinoid necrosis is a special for :

Answer 36

Small blood vessels

Question 37

Appearance of Fibrinoid necrosis in polyarthritis :

Answer 37

Bright pink and homogenously red amorphous appearance

Question 38

Fibrinoid appearance is involved in :

Answer 38

1. Blood vessels in malignant hypertension 2. Blood vessels involved in immune reaction

Question 39

Gangrenous Necrosis :

Answer 39

Infarction + superimposed infection of saprophytic bacterial

Question 40

Types of gangrene

Answer 40

1. Wet gangrene 2.dry gangrene 3.gas gangrene

Question 41

Wet gangrene

Answer 41

Intestine

Question 42

Wet gangrene

Answer 42

DM

Question 43

Gas gangrene

Answer 43

Clostridial welchii infection

Question 44

Gross appearance of gangrenous digit :

Answer 44

The nail is bluish-black The skin is purplish red - cased by thrombosis