Apoptosis Flashcards Preview

Pathology -- Gen Path > Apoptosis > Flashcards

Flashcards in Apoptosis Deck (14):
1

Describe cell morphological changes in apoptosis?

Condensation of cytosol (eosinophilic cytoplasm)
Membrane blebbing into fragments
Fragments phagocytosed by surrounding cells
Cell loss not readily apparent

2

Important differences between apoptosis and necrosis?

Necrosis will extrude its contents, leading to inflamm. Apop will not.
Necrosis has apparent cell loss, apop doesn't necessarily.

3

Causes of physiologic apoptosis (5)

Embryogenesis, Clonal deletion, hormone dependent processes, T cells/Immune Modulation, Maintenance of rapidly dividing.

4

Causes of pathologic apoptosis (5)

Virus
2dary to obstruction, Hypoxia
Heat, Radiation
Cytotoxic Drugs
Tumor-assocaited Necrosis

5

What should you know about Caspases

Carry out protein hydrolysis
Zymogens, Activated by initiator or autocatalytic
Cleave nuclear+cytoskeletal scaffold (lamins)
Cause protein crosslinking
Triggers endonuclease activity

6

How does DNA breakdown in apoptosis happen?

Activation of Ca and Mg dependent endonucleases
First, break into 50-300 kb pieces, then internucleosomal clevage to multiples of 180-200

7

How do phagocytic cells know a cell is apoptotic and should be eaten?

Expression of phosphatidylserine ont he outside of the phospholipid membrane (flipped) or thrombospondin expression

8

Explain the Bcl-2 pathway for regulating mitochondrial fxn

Sensors activate pro-apoptotic members of Bcl-2 family
Release of Cytochrome C as a signal and a docking protein for caspases.

9

name anti-apoptotic proteins

bcl-2, bcl-x

10

name pro-apoptotic proteins

bim, bid, bad
BAX AND BAK

11

Explain the Fas ligand model of apoptosis

Cross linking of TNFR1 or FAS (CD95) allows T cell binding to trigger apoptosis.
Activated surface ligand allows death domain integration into receptor.
Subsequent FADD and Procaspase 8 Activation.

12

So FAS and Bcl-2 lead you up to the execution phase, whats that all about?

Caspases disrupt cytoskeleton+nuclear matrix
Activation of internucleosomal clevage of DNA

13

How do live cells prevent phagocytosis?

Expression of CD31

14

Two methods of CD8 T cell mediated death

FasL binding
Perforin release --> transmembrane pore formation