Pathoma: Cell Death Flashcards

1
Q

What is the morphologic hallmark of cell death?

A

Loss of nucleus

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2
Q

3 ways cell death occurs

A

pyknosis, karyorrhexis, karyolysis

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3
Q

Pyknosis

A

shrinking of nucleus

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4
Q

Karyorrhexis

A

breaking up of nucleus

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5
Q

Karyolysis

A

nucleus broken down into building blocks

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6
Q

2 mechanisms of cell death

A

necrosis

apoptosis

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7
Q

Necrosis

A

death of a large group of cells followed by acute inflammation

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8
Q

Is necrosis pathologic or physiologic?

A

pathologic only

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9
Q

Coagulative necrosis

A

necrotic tissue that remains firm
cell shape and organ structure are preserved by coagulation of cellular proteins
Nucleus disappears

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10
Q

What is coagulative necrosis characteristic of?

A

ischemic infarction of any organ except brain

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11
Q

What is the shape and color of the necrotic tissue?

A

wedge-shaped and pale

wedge points to the area of occlusion

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12
Q

Red infarction

A

arises if blood re-enters a loosely organized tissue

testicle during testicular torsion due to the vein being blocked and blood filling testicle

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13
Q

Liquefactive necrosis

A

necrotic tissue that becomes liquefied

enzymatic lysis of cells and proteins–>liquefaction

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14
Q

What is liquefactive necrosis characteristic of?

A

brain infarction: because of microglial cells that contain hyrolytic enzymes
Abscess: neutrophils contain hyrolytic enzymes
pancreatitis: pancreatic enzymes activated

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15
Q

Gangrenous necrosis

A

coagulative necrosis that resembles mummified tissue (dry gangrene)

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16
Q

What is gangrenous necrosis characteristic of?

A

ischemia of the lower limb and GI tract

if superimposed infection occurs–>liquefactive necrosis ensues (wet gangrene)

17
Q

Caseous necrosis

A

soft, friable necrotic tissue with “cottage cheese-like” appearance
coagulative and liquefactive necrosis

18
Q

What is caseous necrosis characteristic of?

A

granulomatous inflammation due to TB or fungal infection

19
Q

Fat necrosis

A

necrotic adipose tissue with chalky-white appearance due to deposition of Ca2+

20
Q

Saponification

A

fat binding with Ca2+
FA released by trauma or lipase joins with Ca2+
example of dystophic calcification

21
Q

What is fat necrosis characteristic of?

A

trauma to fat (e.g. breast)–>looks like a mass

pancreatitis-mediated damage of peripancreatic fat

22
Q

Metastatic calcification

A

calcification that occurs in multiple tissues due to a high serum Ca2+ or phosphate; not cancerous

23
Q

Fibrinoid necrosis

A

necrotic damage to blood vessel wall

leaking of proteins into vessel wall–>bright pink staining

24
Q

What is fibrinoid necrosis characteristic of?

A

malignant hypertension or vasculitis

preeclampsia–>fibrinoid necrosis of placenta

25
Apoptosis
energy-dependent geneticaly programmed cell death involves single cells or small groups of cells NOT FOLLOWED BY INFLAMMATION
26
Physiologic examples of apoptosis
endometrial shedding during menstrual cycle removal of cells during embryogenesis CD8+ T cell-mediated killing of virally infected cells
27
Morphology of apoptosis
dying cell shrinks (becomes eosinophilic) nucleus condenses and fragments apoptotic bodies fall from cell and are removed by macrophages
28
What mediates apoptosis?
Caspases
29
Caspases
``` activate proteases (break down cytoskeleton) activate endonucleases (break down DNA) ```
30
3 pathways that activate caspases
intrinsic mitochondrial pathway extrinsic receptor-ligand pathway cytotoxic CD8+ T cell pathway
31
Intrinsic mitochondrial pathway
cell injury, DNA damage, or decreased hormonal stimulation inactivates Bcl2 cytochrome c leads from inner mitochondrial membrane-->cytoplasm
32
Extrinsic receptor-ligand pathway
FAS ligand binds FAS death receptor (CD95) on target cell: negative selection during cell cycle of T cell in thymus TNF binds TNF receptor on target cell
33
Cytotoxic CD8+ T cell pathway
perforins create pores in membrane of target cell | granzyme enters pores and activates caspases