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)
What type of necrosis is associated with bacterial infections?
Liquefactive
Liquefactive necrosis is often seen in ___.
Brain hypoxia/infarct
Describe the histology of liquefactive necrosis.
Necrotic amorphous tissue surrounded by a rim of neutrophils
What type of necrosis is associated with a granuloma?
Caseous
Describe the histology of caseous necrosis.
Amorphous debris in the center of a granulomatous cell reaction (lymphocytes, macrophages, giant cells)
What type of necrosis describes cell death in the pancreas and adjacent fat?
Enzymatic fat necrosis
What is gangrene?
Ischemic necrosis of an extremity, bowel, or gallbladder
What is a regulated pattern of cell death characterized by nuclear condensation and fragmentation coupled with fragmentation of cytoplasm into acidophilic bodies, followed by phagocytosis?
Apoptosis
True or false - apoptosis is not associated with an inflammatory reaction.
True
Where is apoptosis seen normally?
- Normal embryogenesis
- Hormone dependent physiologic involution (menstrual cycle)
- Proliferating cell populations (intestinal crypts)
Where is apoptosis seen abnormally?
- DNA damage
- Infections
- Accumulation of misfolded proteins
