L5 Cell Injury Flashcards
Define types of cellular injury Define 7 common causes of Cellular injury Explain difference between reversible and irreversible injury Types of cellular death Types of necrosis
What are the seven causes of cell injury?
- Hypoxia
- Physical agents (temperature, trauma, radiation)
- Chemical agents (drugs)
- Immune reactions
- Infectious agents
- Genetic derangements
- Nutritional imbalance
What biochemical mechanisms cause cell death?
- ATP depletion
- Oxygen and O2-derived free radicals
- Loss of intercellular calcium homeostasis
- Defects in membrane permeability
- irreversible mitochondrial damage
What type of cell injury is being described:
- Decreased ATP generation
- Loss of cell membrane integrity
- Swelling of cell
Reversible cell injury
What type of cell injury is being described:
- Mitochondrial swelling
- Leakage of enzymes
- Swelling of lysosomes
Irreversible cell injury
Characterised by severe mitochondrial changes, failure of plasma membranes and swelling of lysosomes.
How does reversible cell injury become irreversible?
Persistent or excessive injury
What causes ischaemic/reperfusion injury to cells?
Oxygen-derived free radicals
Why does decreased ATP generation lead to cellular injury? Is this reversible or irreversible?
Fewer ATP molecules results in decreased function of the Na/K pumps. This results in too much Na in the cell, which draws in more water (osmosis) and causes the cell to swell.
If ATP generation improves, the cell will begin working as normal and can be salvaged, therefore this is reversible.
What type of molecule activates apoptosis in a cell?
Caspaces
Activated by excessive Ca (due to damaged cell membrane) or Cyt C (leaked from damaged mitochondria).
What are the major changes that occur during necrosis of a cell?
(Hint: SUMO)
Size: many cells affected, cells swell
Uptake: contents ingested by macrophages, significant inflammation
Membrane: lysis and loss or integrity
Organelles: organelles swell and lysosomes leak. DNA randomly degraded.
What are the major changes that occur during apoptosis?
Hint: SUMO
Size: one cell at a time, cell shrinks
Uptake: contents ingested by neighbouring cells, no inflammatory response
Membrane: blebbing allows integrity to be maintained. Formation of apoptotic bodies
Organelles: mitochondria release pro-apoptotic proteins. Chromatin condensation and non-random DNA degradation.
Which type of cell death results in an inflammatory response?
Necrosis
Which type of cell death involves cellular swelling?
Necrosis
Which type of cell death involves caspase activation?
Apoptosis
Which type of cell death involves cell shrinkage and DNA fragmentation?
Apoptosis
Which type of necrosis is most common?
Coagulative necrosis is the commonest form.
Myocardial infarction generally results in which type of necrosis?
Coagulative necrosis
True or false: In coagulative necrosis the cells lose their outlines
False. In coagulative necrosis, cells retain their outlines.
Proteins coagulate and metabolic activity ceases.
Which type of necrosis is seen in the brain? Why?
Liquefactive necrosis. There is a lack of supporting stroma and structures, therefore neural tissue can totally liquify.
Infections usually result in which type of necrosis?
Gangrenous
What is the main cause of caseous necrosis?
Tuberculosis
Which type of necrosed tissue looks like ‘amorphous pink material in centre, with necrotic debris’?
Caseous
Results in structureless dead tissue
Fat necrosis is caused by what?
Enzymes (pancreatic)
Trauma
Which two conditions cause fibrinoid necrosis?
Malignant hypertension
Autoimmune disease
Where is coagulative necrosis most commonly found?
Myocardium
Can occur in all organs but the heart is most common.
Where is liquefactive necrosis seen?
The brain
Which type of necrosis occurs due to lack of substantial supporting stroma?
Liquefactive
Which type of necrosis results in putrefaction of the tissue, caused mostly by infection?
Gangrenous
What are the subtypes of gangrenous necrosis?
Wet
Dry
Gas
Tuberculosis is the main cause of which type of necrosis?
Caseous
Which type of necrosis leads to tissue that looks amorphous pink material in the centre with necrotic debris?
Caseous
What are the main causes of fat necrosis?
Enzymes and trauma
Fibrinoid necrosis is seen in which conditions?
Malignant hypertension
Autoimmune diseases
What are the two possible types of cell injury?
Reversible
Irreversible
What are the possible types of cell death?
Apoptosis and necrosis
What is the most common type of necrosis?
Coagulative
Where is the most common site of coagulative necrosis?
Myocardium
Which necrosis is caused by enzymes and trauma?
Fat necrosis
Which type of necrosis is caused by malignant hypertension and autoimmune diseases?
Fibrinoid necrosis
