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28 Cards in this Set
- Front
- Back
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What is the difference between hypoxia and ischemia?
Which is worse? |
Hypoxia: oxygen deprivation
Ischemia: Loss of Blood Supply Ischemia is more rapidly injurious than hypoxia because of loss of BOTH oxygen and nutrients |
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What are the 4 cellular adaptations to injury?
Are they reversible? |
1. Hyperplasia
2. Hypertrophy 3. Atrophy 4. Metaplasia ALL ARE REVERSIBLE |
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What is hyperplasia?
What is an autoimmune example of hyperplasia? |
An increase in the number of cells in an organ or tissue
Graves Disease: autoantiboides bind to TSH receptor, promote thyroid hyperplasia |
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What is seen microscopically in a thyroid with graves disease?
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Hyperplasia causes too many thyroid cells to maintain a smooth shorelines of colloid lakes so cells bulge out as peninsulas.
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What (generally) often causes hyperplasia?
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Arises from an increased demand for function
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What is hypertrophy?
What often causes it? |
An increase in cell size due to increased protein synthesis (not due to cell swelling)
Often caused by an increased demand for function |
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What is cell atrophy?
What are 5 causes of cell atrophy? |
Decrease in cell size.
Caused by: 1. Decreased Workload (ex: muscle in cast) 2. Decreased blood supply 3. Inadequate Nutrition 4. Loss of endocrine stimulation 5. Denervation (ex: atrophy of skeletal muscle secondary to motor nerve damage) |
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What is a genetic example of cellular atrophy?
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Spinal Muscular Atrophy (SMA) - death of Motor Neurons cause denevation of skeletal muscle which causes muscle atrophy
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What is metaplasia?
What is the classic example? |
A reversible change in the differentiation program of tissue stem cells to a different mature cell type
Classic Example: Squamous metaplasia of the respiratory tract. Pseudostratified columnar epithelium to squamous epithelium |
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What is the main cellular metabolite that is depleted following ischemia?
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ATP - causes failure of membrane pumps (swelling), decrease pH (due to lactic acid buildup)
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What are 4 defenses against free radicals?
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1. Antioxidants
2. Superoxide dismutase: converts superoxide to H2O2 3. Catalase: Decomposes H2O2 4. GSH (recall from Biochem) |
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What 3 types of cell injury can free radicals cause?
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1. DNA Damage
2. Modification of Proteins 3. Lipid Peroxidation |
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What are 2 examples of chemicals that can cause free radical injury?
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1. Carbon Tetrachloride (CCl4)
2. Acetaminophen Both cause damage to hepatocytes because that is where they are metabolized |
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What type of proteins aid in protein folding?
What proteins destroy/recycle misfolded proteins? |
1. Chaperone (ex: Hsp 70)
2. Ubiquitin - tags for destruction |
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What are the 3 patterns of necrosis?
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1. Coagulative Necrosis
2. Liquifactive Necrosis 3. Caseous Necroses |
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What are the characteristics of coagulative necrosis?
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- Most common type of necrosis
- Proteins denature and coagulate, cytoplasm becomes pink on H&E stains - CELLULAR ARCHITECTURE of solid organ is preserved - Characteristic of irreversible ischemic injury to solid organs such as the heart |
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What are the characteristics of liquefactive necrosis?
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- Hydrolytic enzymes predominate over protein denaturation
- Rapid softening with loss of cell outlines (in contrast to coagulative necrosis) - Pattern is characteristic of brain tissue necrosis and some inflammatory reactions |
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A cardiac abscess is a good example of what kind of necrosis?
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Liquefactive Necrosis. Abscess forms and liquefactive necrosis is seen.
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Which type of necrosis is usually observed in the brain?
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Liquefactive
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What infection is usually associated with caseous necrosis?
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TB
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What are 2 main differences between apoptosis and necrosis?
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In apoptosis the plasma membrane remains intact and DOES NOT elicit inflammation
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What is the role of p53?
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p53 normally delays cell cycle, allowing time for DNA repair
When repair mechanisms do not function, it stimulates APOPTOSIS |
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What receptor mediates the extrinsic pathway for apoptosis?
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FASL-FAS
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Why is the permeability of the outer mitochondrial membrane a key step to apoptosis?
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BC the release of items such as cytochrome C make the APOPTOSOME which is needed for apoptosis
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What is the function of the Bcl-2 family of proteins?
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Regulate the permeability of the outer mitochondrial membrane
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What are 3 factors that dictate whether a cell undergoes apoptosis or necrosis?
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1. Type and intensity of cellular insult: More intense cellular insults tend to be associated with necrosis
2. ATP concentration: More rapid ATP depletion tends to be associated with necrosis 3. PARP-1 activation: Severe DNA damage activates PARP-1 which consumes ATP, leading to necrosis |
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What is follicular lymphoma?
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A disease of too little apoptosis
- Bcl-2 constitutively expressed, inhibits apoptosis. - Accumulation of B Cells and lymphoid follicles |
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What is friedrich's ataxia?
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Disease of too much apoptosis
- mutation in frataxin gene, affects mitochondria - causes cardiac hypertrophy and ataxia |
