Cell injury Flashcards
What are the categories of cell injury?
Lethal: causes cell death
Sublethal: produces injury but not amounting to cell death, may be reversible or progress may lead to cell death
What are the types of cell injury?
- Oxygen deprivation
- Chemical agents
- Infectious agents
- Immunological reaction
- Genetic defect
- Nutritional imbalance
- Ageing
- Physical agents
What does cellular response depend on?
- Type
- Duration
- Severity
What do consequence of cell injury depend on?
- Type
- Status (in cell cycle)
- Adaptability
- Genetic make up
What are the 4 intracellular mechanisms most vulnerable to injury?
- Cell membrane integrity
- ATP generation- important in integrity
- Protein synthesis: Affect CM
- Integrity of genetic apparatus
Atrophy:
shrinking in cell size/organs because loss of cell substance
Hypertrophy:
increased size of cell and therefore organ
Hyperplasia:
increased number of cells in organ, can be physiological or pathological
Dysplasia:
precancerous cells which shows genetic and cytological features of malignance but not invading underlying tissue (specifically basal lamina)
What are the light microscopic change in associated with reversible injury?
- Fatty changes
- Cellular swelling
What are the types of necrosis?
- Coagulative: substance change but molecule shape doesn’t
- Liquefactive: empty space, can only identify cells by looking at them around cysts
- Caseous:
- Necrotic area granular making it caseous
- Fat necrosis: associated with acute pancreatitis
- Release of lipases
- Free fatty acid combines with Ca
- Ulcer: local defect of surface of organ/tissue produced by sloughing of necrotic inflammatory tissue
What occurs during apoptosis?
- Active
- Physiological or pathological
- Cell shrinks and little bits break off lined by cytoplasm
- Nothing from inside the cell is exposed to the outside so as to not cause inflammation
- Then phagocytosed
What are the causes of apoptosis?
- Embryogenesis: intestine shave lumen because apoptosis during development
- Deletion of autoreactive T cells in thymus
- Hormone dependent physiological involutions - endometrium shedding
- Cell deletion in proliferating population
Variety of mild injurious stimuli causing irreparable DNA damage that triggers cell suicide pathway
Apoptosis vs. Necrosis.
- Apoptosis may be physiological
- Apoptosis is active energy dependant process
- Apoptosis is not associated with inflammation
