L1 Cell Injury Flashcards
What is disease?
The reaction of a cell or group of cells to an injury
What 2 broad effects can an injury have on a cell?
- Disrupt biochemical processes of the cell (function)
2. Damage components of the cell directly (structure)
What is the etiology of a disease?
The cause of the disease
What is the pathogenesis of the disease?
The mechanisms of disease
What are the 8 general etiologies of injury?
- Hypoxia (oxygen deprivation)
- Chemical
- Physical
- Infectious
- Immunologic
- Genetic
- Nutritional
- Degenerative (aging)
What are the three ways cells change in the adaptation process?
- Size
- Number
- Appearance
What are the 4 types of cell adaptation?
- Hyperplasia
- Hypertrophy
- Atrophy
- Metaplasia
What is hyperplasia?
Increase in the number of cells
What is hypertrophy?
Increase in the size of a cell because of increased cellular substance
What is atrophy?
Decrease in the size of a cell because of loss of cellular substance
What is metaplasia?
Substitution of one type of an adult cell for another type of adult cell
A normal cell reacts to stress by ___. When this cannot occur, or when injurious stimuli occur, ___ results. What are the two outcomes of this?
Adapting; cell injury; reversible injury, irreversible injury
True or false - as cell function decreases, changes are readily apparent.
False - cell function decreases before we can see changes
What are the two features of irreversible cell injury?
- Non-repairable mitochondrial dysfunction
- Profound membrane dysfunction
(membrane & mito)
What are the 5 major mechanisms of cell injury?
- Hypoxia and ischemia (decreased ATP)
- Multiple injurious stimuli (increased ROS)
- Mutations, cell stress, infections (accumulation of misfolded proteins)
- Radiation, other insults (DNA damage)
- Infections, immunologic disorders (inflammation)
Describe the hypoxic injury model.
Ischemia, hypoxemia, or decreased oxygen carrying capacity –> decreased oxidative phosphorylation in the mitochondria –> decreased ATP –> 3 things:
- Decreased sodium pump –> increased influx of calcium, water, sodium, efflux of potassium –> ER/cellular swelling, loss of microvilli, blebs
- Increased anaerobic glycolysis –> decreased glycogen, increased lactic acid, decreased pH
- Detachment of ribosomes –> decreased protein synthesis
What can be measured clinically to check for altered membrane permeability?
Levels of intracellular enzymes in vasculature
Examples: elevated CK or troponin in myocardial cells (acute MI), elevated AST/ALT in hepatocytes (hepatitis)
What is reperfusion injury?
Further injury to cells when blood/oxygen returns to ischemic tissue; caused by free radicals (from leukocytes)
What are the 5 components of the morphology of reversible cell injury?
- Cellular swelling
- Steatosis (fatty change)
- Myelin figures (collections of phospholipids)
- ER swelling
- Membrane blebs
What is necrosis?
The sum total of morphologic changes which occur in tissue following cell death
The presence of ___ is characteristic of necrosis.
Leukocytes (especially neutrophils) infiltrating dead tissue.
What are the 5 morphologic patterns of necrosis?
- Coagulative
- Liquefactive
- Caseous
- Enzymatic fat
- Gangrene
What type of necrosis is associated with severe ischemia in solid organs?
Coagulative necrosis
Describe the histology of coagulative necrosis.
Ghost-like remnants of intact cells which lack nuclei; cell outline preserved; eosinophilia (cytoplasm stains pink)
