Ch2 Cell Death EC

Question 1

Necrosis

Answer 1

Death of groups of cells + inflammation

Question 2

Coagulative necrosis

Answer 2

Preservation of structural outlines

Question 3

Mechanism of coagulative necrosis

Answer 3

Denaturation of enzymes and structural proteins (lactate, heavy metals, ionizing radiation)

Inactivation of intracellular enzymes

Question 4

Microscopic features of coagulative necrosis

Answer 4

Indistinct outlines of cells within dead tissue

Nuclei absent

Question 5

Infarction

Answer 5

Gross manifestation of coagulative necrosis due to sudden occlusion of a vessel

Question 6

Pale (ischemic) infarcts

Answer 6

Dense tissue

heart, kidney, spleen

Question 7

Hemorrhagic (red) infarcts

Answer 7

Loose tissue

lung, bowel, testicle

Question 8

Dry gangrene

Answer 8

Toes in DM is a form of infarction that results from ischemia with coagulation necrosis

Question 9

When is an infarction less likely to occur?

Answer 9

Dual blood supply (lungs)
Collateral circulation (arcade system of superior/inferior mesenteric arteries)
Preexisting disease

Question 10

Mechanism of liquefactive necrosis

Answer 10

Release of lysosomal enzymes by necrotic cells or by the release of hydrolytic enzymes by neutrophils

Question 11

Examples of liquefactive necrosis

Answer 11

Cerebral infarction (via hydrolytic enzymes from neuroglial cells)
Abscess in bacterial infection (via hydrolytic enzymes released by neutrophils)

Question 12

Wet gangrene

Answer 12

Predominantly liquefactive necrosis

Dry gangrene + superimposed anaerobic infection (C. perfringens)

Question 13

Mechanism of caseous necrosis

Answer 13

Produced by lipid from cells walls of mycobacterium and fungi after immune destruction by macrophages in granulomas

other granulomas as noncaseating because they lack excessive amounts of lipid

Question 14

Gummatous necrosis

Answer 14

Type of coagulation necrosis
Associated with spirochetal disease (syphilis)
Hypersensitivity directed against spirochetes

Question 15

Mechanism of enzymatic fat necrosis

Answer 15

Activation of pancreatic lipase causes hydrolysis of TGs in fat cells
Calcium combines with fatty acids via saponification

Question 16

Traumatic fat necrosis

Answer 16

Necrosis in fatty tissue as a result of trauma

Non-enzymatic (unlike pancreas)

Question 17

Fibrinoid necrosis

Answer 17

Necrosis that may occur in small muscular arteries, arterioles, venules, glomerular capillaries, valve leaflets, myocardium, and subcutaneous tissue

Question 18

Mechanism of fibrinoid necrosis

Answer 18

Deposition of pink-staining proteinaceous material in damaged tissue
Necrosis of immune-mediated disease

Question 19

Extrinsic apoptosis pathway (death receptor pathway)

Answer 19

TNFR1 binds TNF-alpha
Fas-R binds Fas-Ligand
(Perforin and granzyme B in immune cells)

Activation of initiator caspases (8&10)
Activation of effector caspases
~Protease destroys cytoskeleton
~Endonuclease causes pyknosis of nucleus

Question 20

Intrinsic apoptosis pathway (mitochondrial pathway)

Answer 20

BCL-2 stabilizes cytochrome c in mito. membrane (anti-apoptotic)
BAX/BAK form channels in mito. membrane (pro-apoptotic)
Cytochrome C complexes with another protein activating initiator caspase 9
Activation of effector caspases
~Protease destroys cytoskeleton
~Endonuclease causes pyknosis of nucleus

Question 21

Microscopic appearance of apoptotic cells

Answer 21

Deeply eosinophilic
Nucleus pyknotic, fragmented, or absent
Minimal inflammation

Question 22

Pyroptosis

Answer 22

Proinflammatory cell death using caspase-1

Monocyte cell destruction of Salmonella, Shigella, Legionella

Question 23

What are some examples of pathologic activation of caspase-1?

Answer 23

MI
Neurodegenerative disease
IBD
Cerebral ischemia
Endotoxic shock

Question 24

Aspartate aminotransferase (AST) diagnostic use

Answer 24

Marker of diffuse liver cell necrosis

Mitochondrial enzyme preferentially increased in alcohol-induced liver disease

Question 25

Alanine aminotransferase (ALT) diagnostic use

Answer 25

Marker of diffuse liver cell necrosis (ie viral hepatitis)

More specific for liver cell necrosis than AST

Question 26

Creatine kinase MB (CK-MB) diagnostic use

Answer 26

Isoenzyme increased in acute MI or myocarditis

Question 27

Amylase and lipase diagnostic use

Answer 27

Marker enzymes for acute pancreatitis

Lipase more specific than amylase (also increased in salivary gland inflammation [mumps])