POM 03 - Cell injury and inflammation Flashcards
what are the 6 possible causes of cell stress and injury
physical injury
chemical injury
biological causes (eg viral infection)
immunological causes
genetic derangements
nutritional imbalances
what are the 3 outcomes that cell injury can lead to
no effect
adaptation
cell injury
what does it mean when the injurious agent or stress has no effect on the cell
the cell can cope with it, can function and survive in hostile environment
what does it mean when the injurious agent or stress causes adaptation in the cell
the cell can change itself in order to resist or adapt to the injury
what does it mean when the injurious agent or stress results in cell injury
there is a physical and biochemical change in the cell beyond amount of injury that can be fixed by turning on signal pathways and generating adaptation
cell injury can either be __ or __
irreversible leading to death or reversible
what is an example of cells that are no affected by injurious agents or stress
neutrophils
what is adaptation in cells a response to (2 things)
mild injurious agents
mild stress
what is an example of mild injurious agents
chronic irritant
what is an example of mild stress
altered environmental conditions
what does adaptations allow the cell to do
allows cell to continue to function without being injured despite the stress or change in environment
what are the 4 types of adaptation a cell can undergo
hypertrophy
hyperplasia
atrophy
metaplasia
what is hyperplasia
number of cells increases by stem cell dividing due to increased demand on cell
is adaptations in cell (the 4 types) active/passive processes and what drives them
active process
driven by signalling pathways
what is hypertrophy
individual cells gaining size - NOT increasing number of cells
what is atrophy
cells shrink smaller in size
what is metaplasia
stem cells reprogram themselves in order for cells to be better adapted in hostile environment
what are two broad types of signalling pathways that are activated by cell stress/injury
heat shock factors
stress enzymes
what are heat shock factors
transcription factors which induce expression of heat shock proteins which act in a circular loop that further activates heat shock factors
which two stress enzymes initiate the phosphorylation cascades
p38 MAP kinase
Jun N-terminal kinase
what does the p38 MAP kinase and Jun N-terminal kinase enzymes initiate
phosphorylation cascades
what is p53 activated by
DNA damagew
hat does p53 do to cell division and why
halts it to allow repair so they dont perpetuate damage while repairing or induces cell suicide
what does p53 sense
senses DNA damage
what is BMF a sensor for
actin cytosckeleton damage
what is Bim a sensor for
microtubule damage
what is Bad a sensor for
cell stress due to inadequate stimulation by growth factors
what are 3 stress enzymes starting with B
BMF
Bim
Bad
what is BMF, Bim and Bad examples of
stress enzymes
what are the 4 main cellular components that are due to the effect of stress/injury on cells
decreased ATP/energy
membrane damage
increased intracellular Calcium
reactive oxygen species
why does depletion of ATP occur in cell - 3 reasons
less ATP produced due to:
lack of oxygen (blood supply interrupted = less removal of CO2 = prevents oxidative phosphorylation)
damage to enzymes involved in ATP production
damage to mitochondria (decreases aerobic respiration)
why is decreased ATP in cell injury bad for the cell - 3 things
enzymes that repair damaged DNA needs ATP
ATP driven membrane pumps need ATP
protein synthesis needs ATP
what happens to when ATP driven membrane ion pumps dont have enough ATP - Na+ pumps
Na+ pump doesn’t work as well without ATP so sodium and water accumulate = cell swelling = can burst, lose function and alter tissue architecture
what happens to when ATP driven membrane ion pumps dont have enough ATP - Ca2+ pumps
Ca2+ pump doesnt work as well without ATP so Ca2+ influx into cytosol = activates destructive Ca2+ dependent enzymes (can lead to autolysis)