Path IV Flashcards
What are some cytoplasmic features of necrosis?
increased cytoplasmic eosinophilia, calcification
What are some nuclear features of necrosis?
karyolysis leading to fading of basophilia of DNA
pyknosis: nculear shrinkage into a ball with increased basophilia
karyorrhexis: fragemntation of of pyknotic or karyolyitic nuclei
What is the morphology of an apoptotic cell?
shrunken, dark cell with pyknotic nucleus and fragmentation of the the cell into apoptotic bodies. followed by phagocytosis.
How do we regulate the size of a cell population?
altering the rate of cell death or changing the rate of cell proliferation and differentiation.
What are the three kinds of cells in the body, grouped by how often they divide?
- continuously dividing cells: epithelium, hematopoetic cells
- quiescent cells: low levels of activity and division but can be greatly upregulated in times of need: kidney, liver, pancreas, endothelial cells
- non-dividing cells: cells that don’t divide post-natally: neurons, cardiac myocytes, most skeletal muscle
What signaling goes on in the extrinsic pathway for apoptosis?
cell surface molecules like TNFR1 or Fas bind TNF-family molecules.
this leads to the aggregation of intracellulatr death domains (FADD)
we then se a proteolytic cascade where the final result is the activation of caspases.
What roles does TNF play in the cell?
may promote apoptosis by leading to the aggregation of intracellular death domains or may oppose apoptosis by degrading inhibitors of anit-apoptotic proteins (like NF-kB).
How do cytotoxic T cells promote apoptosis using the extrinsic death pathway?
via interacting with Fas receptors of the (soon-to-be) apoptotic cells. T cells have Fas ligand on their surfaces.
How does the intrinsic apopotic pathway work?
Normally, Bcl-2 is found on the surface of the mitochondria and is bound by growth factors and hormones. If this stimulus disappears, Bcl-2 decreases. Or, sensors of damage and stress like Bim, Bad, and Bid are activated leading tho the insertion of Bax and Bak into the mitochondrial membrane. Mitochondria leaks cytochrome c, cytochrome c binds cytoplasmic Apaf-1, and caspases are activated.
How does severe DNA damage promote apoptosis?
severe DNA damage leads to the accumulation of p53, which interacts with Bcl-2 and promotes apopotosis.
What happens during the execution phase of apoptosis?
activation of executioner caspases 3 and 6 by initiator caspases 8 and 9. they cleave each other, the cytoskeleton, and nuclear matrix proteins. DNases are activated and macrophage stimulatory factors are released.
How do cytotoxic T cells promote apoptosis directly?
they perforate the cell membrane with perforin and inject granzyme protease, which activates executioner caspases.
What happens during autophagy- what is its function and what occurs?
this is the lysosomal degradation of a cell’s own components.
it removes organelles that were damaged during injury or aren’t needed due to cellular remodeling. it also digests unneeded proteins. stuff is organelles are sequestered in an autophagic vaculue, which fuses w/ lysosome to make an autolysosome. digested materials may be recycled.
What is the difference between exogenous and endogenous intracellular accumulation?
endogenous: describes materials that are naturally occuring in the body
exogenous: describes materials that are ingested or absorbed from the environment.
Why do normal endogenous/exogenous things accumulate?
synthesis/absorption is up or degradation/metabolism/export is down.
