Cell injury Flashcards
What is cell injury a response to? Give examples
Stress or stimuli
Infectious agents, decreased O2, nutritional deficiencies, trauma
What does the cells response to injury depend on?
Type of cell
State of cell
Adaptability of cell
What do reversible and irreversible changes cause in response to cell injury?
Reversible - decreased function
Irreversible - structural/microscopic/gross changes then death
What ultimately causes death after irreversible cell injury?
Massive influx of calcium
Causes necrosis and apoptosis
What organelles are vulnerable to cell injury?
Cell membrane
Mitochondria
Protein synthesis
DNA
How does damage to mitochondria lead to cell death?
Damage decreases ATP
Lack of cell energy for respiration (decreased oxidative phosphorylation)
What is ischaemia?
Restricted blood supply
Are ischameia and hypoxia reversible or irreversible?
Irreversible
Lack of substrates for glycolysis and oxidative phosphorylation
What effects does ischaemia cause?
Swelling
Decreased pH
Decreased protein synthesis
What causes cells to die after blood flow is resumed following ischaemia/hypoxia?
Hypoxic cells express oxygen free radicals and cytokines
Cause inflammation and death
Oxidative stress is cell injury due to oxygen and oxygen free radicals. How does increased oxygen kill cells?
Increased O2 forms hydrogen peroxide
How does loss of intracellular calcium homeostasis (increased calcium) cause cell injury?
Hypercontraction of muscles
Activates ATPase and phospholipidase, protease (decreases ATP, phosphate and proteins)
How does membrane damage cause cell injury?
Allows oxygen to leave - hypoxia
Causes calcium to enter cell
How do chemicals directly cause cell injury?
Chemicals combine with organelles or chemicals converted to toxic metabolites
