Cell Death Flashcards
what is atrophy?
reduction in cell size/number
what are the two types of cell death?
necrosis
apoptosis
which type of cell death requires energy?
apoptosis
which type of cell death NEVER occurs physiologically, is always pathological?
necrosis
what are the three types of necrosis?
coagulative
liquefactive
caseous
describe coagulative necrosis
the cell outline is preserved
dead cells are consumed by enzymes and cells
when is coagulative necrosis often seen?
after an MI in cardiac muscle
describe liquefactive necrosis
cells become a liquid mass and no cell structure remains
what is produced by liquefactive necrosis?
pus
what type of necrosis occurs in the brain after a stroke?
liquefactive
what is liquefactive necrosis associated with?
localised bacterial and fungal infections
what is caseous necrosis often associated with?
TB
what three tests should you ask for if someone has suspected TB?
culture
PCR
ziehl neelsen stain
describe caseous necrosis
granulomatous inflammation with central necrosis
what is apoptosis?
programmed cell death in response to specific signals
when could apoptosis be physiological?
the removal of self reactive lymphocytes
when does pathological apoptosis occur?
in response to injury
what are the two pathways of apoptosis and what do they both rely on?
intrinsic and extrinsic
the activation of caspases
what activates the extrinsic pathway of apoptosis?
death receptors binding to the death domain on the cell membrane
stimulates caspases
name two death receptors?
TNF and Fas
where does Fas cause apoptosis?
in autoimmune lymphocytes
where does TNF cause apoptosis?
in association with inflammatory conditions
what type of pathway is the intrinsic pathway of apoptosis?
mitochondrial
how does the intrinsic pathway cause apoptosis?
anti-apoptotic molecules in mitochondrial membrane replaced with Bac and Bax
increased mitochondrial permeability
proteins released that stimulate caspases
name a protein released by the mitochondria that can activate caspases
cytochrome C
what can too little apoptosis cause?
cancer
autoimmune disorders
what can too much apoptosis cause?
neurodegenerative disorders
name two causes of cellular aging
oxidative stress
accumulation of metabolic by-products
