L5 - Cell injury and Cell death Flashcards
what are the two cellular adaptions a cell can make in response to external pressures?
hypertrophy
atrophy
what is necrosis?
Severe cell swelling and rupture (not programmed)
what is apoptosis?
Internally controlled cell death (programmed)
what is oncosis?
Pre lethal changes preceding cell death
what are causes of cell injury?
• Hypoxia • Physical agents – Temperature, trauma, radiation • Chemical agents – Drugs etc • Immunologic reactions • Infectious agents • Genetic derangements • Nutritional imbalances
how does trauma cause cellular injury?
Mechanical disruption of tissue
how does carbon monoxide inhalation cause cellular injury?
Prevents oxygen transport
how does contact with strong acid cause cellular injury?
Coagulates tissue protein
how does a paracetamol overdose cause cellular injury?
Metabolites bind to liver cell protein and lipoproteins
how do bacterial infections cause cellular injury?
Toxins and enzymes
how does ionising radiation cause cellular injury?
Damage to DNA
a cell experiences swelling, pallor, hydropic change, vacuolar degeneration - what type of injury is this?
reversible
what are the 3 types of. cellular injury?
reversible
irreversible
ischaemic/reperfusion
a cell experiences Mitochondrial swelling, lysosomes swells, damage to membrane,
leakages of enzymes
- what type of injury is this?
irreversible
a cell experiences New damage on reperfusion mediated by free oxygen radicals - what type of injury is this?
Ischaemic/Reperfusion injury
features of a reversible cell injury?
- decreased generation of ATP
- loss of cell membrane integrity
- defects in protein synthesis and DNA damage
(cell shuts down to. concentrate on surviving)
features of a irreversible cell injury?
- severe mitochondrial. changes
- extensive damage to plasma membranes
- swelling of lysosomes
how does the degeneration of ATP in reversible cell injury, lead to cellular swelling?
- decreased ATP
- decreased activity of Na/K pump
- increased Na inside of cell
- water comes into cell (osmosis)
- cell swells
in an irreversible cellular injury, membrane damage to lysosomes can cause what?
- leakage of lysosomal enzymes into cytosol
- enzymatic degradation of cell
in an irreversible cellular injury, membrane damage to the cell membrane can cause what?
- increased Ca inside cell which activates proteases and other enzymes
- enzymatic degradation of cell
in an irreversible cellular injury, membrane damage to mitochondria can cause what?
- cytochrome c. leakage
- activates caspaces which triggers apoptosis
features of apoptosis?
• Programmed cell death
• Individual cell deletion
• Activated or prevented by many stimuli
• Increased apoptosis results in excessive cell loss e.g,
atrophy
features of necrosis?
• Death of tissue following bioenergy failure and loss of plasma
membrane integrity
• Includes inflammation and repair
what happens to the size of a cell in necrosis compared to apoptosis?
necrosis:
- cellular swelling
- many cells affected
apoptosis:
- cell shrinkage
- one cell affected
what happens to the uptake of a cell in necrosis compared to apoptosis?
necrosis:
- contents ingested by macrophages
- significant inflammation
apoptosis:
- contents ingested by neighbouring cells
- no inflammatory response
what happens to the membrane of a cell in necrosis compared to apoptosis?
necrosis:
- loss of membrane integrity
- cell lysis occurs
apoptosis:
- membrane blebbing but integrity maintained
- apoptotic bodies form.
what happens to the organelles of a cell in necrosis compared to apoptosis?
necrosis:
- organelle selling and lysosomal leakage
- random degradation of DNA
apoptosis:
- mitochondria release pro-apoptotic proteins
- chromatic condensation and non-random DNA degradation
chromatic condensation is a feature of necrosis or apoptosis?
apoptosis
cell lysis is a feature of necrosis or apoptosis?
necrosis
organelle swelling is a feature of necrosis or apoptosis?
necrosis
membrane blebbing is a feature of necrosis or apoptosis?
apoptosis
an inflammatory response is a feature of necrosis or apoptosis?
necrosis
what is autophagy?
cell dissembles itself/eats itself to provide energy to surrounding cells
NB: normal natural response - no inflammatory response
what are the 6 types of necrosis?
- coagulative
- liquefactive
- gangrenous
- caseous
- fat necrosis
- fibrinoid necrosis
what is the most common form of necrosis?
Coagulative Necrosis
features of Coagulative Necrosis?
- cells retain their outlines
- architecture preserved but loss of proteins/enzymes and metabolic activity
features of Liquefactive Necrosis?
• Seen in brain • Due to lack of substantial supporting stroma • Neural tissue may totally liquify
what type of necrosis is seen in the brain?
Liquefactive Necrosis
features of Gangrenous Necrosis?
• Putrefaction of the tissue • Cause is mostly infectious/ bacteria. • Appear black • Types – Wet gangrene – Dry gangrene – Gas gangrene
what are the 3 types of gangrenous necrosis?
– Wet gangrene
– Dry gangrene
– Gas gangrene
what is the main cause of Caseous Necrosis?
tuberculosis
features of Caseous Necrosis?
• looks like cottage cheese • Tuberculosis is main cause • Structureless dead tissue • Amorphous pink material in centre with necrotic debri
what are the two causes of fat necrosis?
enzymes
trauma
what two conditions is fibrinoid necrosis seen in?
malignant hypertension
autoimmune diseases
what type of necrosis is seen in autoimmune disease?
fibrinoid necrosis
what type of necrosis is seen in malignant hypertension?
fibrinoid necrosis
what is the most common site of Coagulative necrosis?
myocardium
