Cell injury & death Flashcards
Describe the cells response to stress?
- Cell tries to adapt
- If stress exceeds adaptability –> injury
- If injury is irreversible –> cell death
What are 7 causes of cell injury + death?
- Oxygen deprivation
- Physical agents
- Chemicals & drugs
- Infectious agents
- Immune reactions
- Genetic derangements
- Nutritional imbalances
How can you detect cell injury?
Look for intracellular components in the blood - increased levels indicates loss of integrity of cell membrane
What are the two types of cell death?
- Necrosis
- Apoptosis
Describe necrosis
- Something causes injury to cell
- Pathologic
- Enzymatic cell digestion
- Cell contents leak out - causes inflammation
- Cell size enlarges
Describe apoptosis
- Programmed cell death
- Pathological or physiologic
- Internally controlled
- Nuclear dissolution
- Cell size shrinks
When is cell injury irreversible?
- Severe mitochondrial damage
- Rupture of lysosomal & plasma membranes
How does mitochondrial damage cause cell injury?
- Less ATP produced
- Free oxygen species produced
- Pores in Mt membrane –> leakage of Mt proteins
How does loss of Ca homeostasis cause cell injury?
Influx upon cell injury to activate enzymes for apoptosis
How do free oxygen species cause cell injury?
From Reactive Oxygen Species (ROS)
What causes increased free radical generation?
- Absorption of radiant energy
- Enzymatic metabolism of exogenous chemicals
- Activation of inflammation
How are free radicals removed?
- Spontaneous decay
- Anti-oxidants
- Storage proteins
- Enzymes
How do free radicals injure cells?
- Membrane lipid peroxidation
- Interaction with proteins
- DNA damage
What are the 6 types of necrosis?
- Coagulative - no enzymatic digestion of tissue
- Liquefactive - replaces cell with liquefied material
- Caseous - looks like cottage cheese (TB)
- Gangrenous -
- Fat - no strictly necrosis - enzymatic digestion of tissues
- Elbrinoid
What is infarction?
Area of ischaemic necrosis in a tissue or organ
