1.3 Cell Death Flashcards
1
Q
What happens intracellularly in cell necrosis: (3 steps)
A
- loss of nucleus, in 3 steps
1. Pyknosis–nuclear condensation
2. Karryorhexis–nuclear fragmentation
3. Karryolysis–nuclear dissolution
2
Q
2 main mechanisms of cell death
A
Necrosis, Apoptosis
3
Q
Types of gross necrosis (6)
A
- Coagulative necrosis
- Liquefactive necrosis
- Gangrenous necrosis
- Caseous necrosis
- Fat necrosis
- Fibrinoid necrosis
4
Q
Coagulative necrosis
- histological finding
- gross finding
- characteristic of what
A
- necrotic tissue remains firm. Cell shape preserved, but nucleus disappears
- organ structure preserved, often wedge-shaped infarct
- characteristic of ischemic infarct of all organs except brain
- Red infarct: Blood pools without venous drainage (ex: testicles)
5
Q
Liquefactive necrosis
- what is it
- characteristic of what (3 examples)
A
- necrotic tissue is liquefied from enzymes, eg leukocyte enzymes
- makes Pus if acute inflammation with neutrophils
- characteristic of :
1. brain infarct (microglial cell enzymes)
2. abscess (neutrophil enzymes)
3. pancreatitis (pancreatic enzymes)
6
Q
Gangrenous necrosis
- gross findings
- characteristic of what
- 2 types
A
- Not a ‘true’ necrosis type–it’s coagulative necrosis
- Dry: Coaguative necrosis that resembles mummified tissue
- characteristic of ischemia of lower limb, GI tract
- Wet: infection of dead tissues causes additional liquefactive necrosis
7
Q
Caseous necrosis
- gross finding
- characteristic of what?
A
- soft, “cottage cheese”
- combo of coagulative and liquefactive necrosis
- Granulomatous inflammation from TB or fungal infection
- ex: TB lung infection
8
Q
Fat necrosis
- what is it
- characteristic of what (2 main examples)
- Mech?
A
- necrotic adipose tissue, chalky-white appearance from Ca deposition
- characteristic of:
1. trauma (eg breast)
2. pancreatitis-mediated damage (lipase) of peripancreatic fat - Mech: Saponification. Fatty acids released are calcified by Ca.
9
Q
Fibrinoid Necrosis
- histological finding
- characteristic of what
A
- vessel wall necrosis
- microscope: Bright pink vessel wall
- caused by deposits of Ab/Ag complexes into vessel wall, as well as leakage of fibrin from vessel
- malignant hypertension, vasculitis
10
Q
Apoptosis
-describe cellular pathways (3).
A
- mediated by caspase activation, which activate proteases and endonucleases
1. Intrinsic mitochondrial pathway - Cell injury inactivates Bcl2, which keeps Cyto C from leaking from mito.
2. Extrinsic receptor-ligand pathway
a. FAS ligand binds FAS death receptor (Thymic T cell negative selection)
b. TNF binds TNF receptor on target cell
3. CD8 T-cell pathway - Killing of virus-infected cells with Perforins, Granzyme.
11
Q
Morphologic hallmark of cell death
A
Loss of nucleus
