Cell injury/inflammation/apoptosis/necrosis

Question 1

bcl2

Answer 1

inhibits Apaf-1 –> normally stimulates caspases
inhibits cytochrome C
increased in some cancers = no death of cells

Question 2

bax and bak

Answer 2

proapoptotic

cause release of cytochrome c

Question 3

CD95

Answer 3

FasL for Fas extrinsic pathway - FADD - activation of caspases

Question 4

Coagulative necrosis - where? when? what do you see?

Answer 4

ischaemic infarcts everywhere but brain
proteins denature and then enzymes degrade
cell outlines preserved - increased acidophilic binding

Question 5

liquefactive necrosis - where? when? what do you see?

Answer 5

bacterial absecess and brain (due to increased fat content)
PMN release lysosomal enzymes
enzymes degrade then proteins denature
early: cellular debris and macrophages
later: cystic spaces and cavitation @ brain, PMN and cell debrin @ bacterial

Question 6

caseous necrosis - where? when? what do you see?

Answer 6

Tb, systemic fungi (histoplasma), nocardia
macrophages wall off infecting moo - granuloma debris
fragmented celsl and debris surrounding by lymphocytes and MO (TH1)

Question 7

fat necrosis - where? when? what do you see?

Answer 7

acute pancreatitis = enzymatic (saponification)
breast trauma = non enzymatic
damaged cell release lipases – fatty acids in cell membrane break down
outlines of dead fat cells without peripheral nucles
saponidficaiton with Ca is dark blue

Question 8

fibrinoud necrosis - where? when? what do you see?

Answer 8

immune reaction in vessels
immune complexes combine with fibrin
vessel walls are thick and pink

Question 9

gangrenous necrosis - where? when? what do you see?

Answer 9

distal extremities after chornic ischaemia
dry - ischaemia - coagulative necrosis
wet - superinfeciton - liquefactive

Question 10

list the iscahemia susceptible areas

Answer 10

brain @ MCA, PCA, ACA - watershed and hypoxis ischemic encehalopathy
heart @ subendothelium in LV
kidney @ straight portion of proximal tubule and thick ascending loop of henle (both are in medulla)
liver @ area around central vein ie zone 3
colon @ splenic flexure, rectum - watershed

Question 11

where do red infarcts occur?

Answer 11

tissues with multiple blood supplies
venous occlusion
liver, lung, intestine

Question 12

where do pale infarcts occur?

Answer 12

tissues with end arterial blood supplies
end arterial
sold organs ie heart, kidney, spleen

Question 13

describe chromatolysis

Answer 13

involves neuronal cell body after axonal injury; increase in protein synthesis to try and repair axon

a) round cellular swelling
b) displacement of the nucleus to the periphery
c) dispersion of nissl substance throughout cytoplasm