apoptosis and necrosis Flashcards
apoptosis
programmed cell death (of a single cell)
Give an example where apoptosis is important physiologically
embryogenesis - removal of tissue between digits
Which gene checks for DNA damage?
p53
Give an example where lack of apoptosis causes disease
cancer
virtues enhance their survival by inhibiting apoptosis
define necrosis
traumatic cell death (causing death of cells in bulk)
unprogrammed cell death of a large number of cells due to an adverse event such as infarction, burns, frostbite etc
Give some clinical examples of necrosis
frostbite cerebral infarction toxic spider venom avascular necrosis of bone pancreatitis (fat necrosis) TB - caseous necrosis
Give another term used for excessive cell loss by apoptosis
atrophy
what does loss of p53 function result in
neoplasia
Give examples of disease where there is excessive/inappropriate apoptosis
HIV neurodegernative disorders anaemia of chronic disorders autoimmune disease GvHD
Outline brief steps of necrosis
- failure of ATP production causes plasma membrane pumps to become ineffective
- loss of homeostasis, influx of water, oncosis, lysis and cell death
- This induces inflammation and repair (to remove the cell)
What are the differences in biochemical events between apoptosis and necrosis?
apoptosis:
energy dependent fragmentation of DNA
lysosomes remain intact
necrosis:
energy failure
impairment of ion homeostasis
lysosomes leak lytic enzymes
What are the differences in cell membrane integrity between apoptosis and necrosis?
cell membrane maintained in apoptosis
membrane integrity lost in necrosis
what are the differences in morphology between apoptosis and necrosis
apoptosis:
cell shrinkage
apoptotic bodies
dense chromatin
necrosis:
cell swelling and lysis
What are the differences in inflammatory response between A and N.
A: none
N: present inflammatory response (phagocytksed by neutrophils and macrophages)
