Term
| Describe the patterns of necrosis at the cellular level (shown by all) |
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Definition
Eosinophilia
Cytoplasm becomes vaculoated
Inflammation
Nucleus lives a day or so before fading away completely |
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Term
| Describe coagulative necrosis |
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Definition
Denaturation - proteins coagulate, metabolism stops
H&E shows inflammation and collagen is less affected so structure remains |
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Term
| Describe colliquative / liquefactive necrosis |
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Definition
| Enzyme degeneration (pus if infective). If no supporting structure can lead to a cyst. |
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Term
| Describe caseative necrosis |
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Definition
| Coagulation with granular debris and granulomata. Often calcification. |
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Term
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Definition
| Direct trauma or lipases. Not a distinct form of necrosis |
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Term
| Describe fibrinoid necrosis |
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Definition
| Necrosis of SM wall - plasma and fibrin in wall. Accumulation of amorphous, basic, proteinaceous material in the tissue matrix with a staining pattern reminiscent of fibrin |
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Term
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Definition
Liquefactive necrosis putrefaction.
Occurs especially in the bowel and distal limbs |
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Term
| What is the sequelae of necrosis? |
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Definition
| Complete removal --> Organisation --> Calcification |
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Term
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Definition
| Energy dependent process of deletion of unwanted cells |
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Term
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Definition
| Spectrum of morphological changes following cell death in living tissue |
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Term
| Describe the morphological changes that occur during apoptosis (5) |
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Definition
1. Shrinkage
2. Condensed chromatin under nuclear membrane
3. Blebbing - forming apoptotic bodies
4. Phagocytosis, including by neighbouring cells
5. No inflammation - can be cleared quickly |
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Term
| Describe the stages of apoptosis |
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Definition
| Signalling --> Control and integration --> Execution --> Removal of dead cells |
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Term
| What are the three types of signalling that occur during apoptosis |
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Definition
Fas (CD95) signalling
T cell killing
DNA damage |
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Term
| Why is there no inflammation in apoptosis? |
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Definition
| Because the removal of dead cells is by phagocytes - marker molecules make this an efficient process and there is no inflammation |
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Term
| List some disorders of apoptosis (too little / too much) |
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Definition
Too little = cancer, autoimmune
Too much = neurodegeneration, AIDS |
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Term
| Describe the ultra-structural changes occurring in cell adaptation and sub-lethal injury |
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Definition
Swelling of cell and organelles, especially in mitochondria and ER
Blebbing
Detachment of ribosomes
Loss of microvilli
Myelin figures
Surface blebs
Chromatin clumping
Lipid deposition
Loosening of intercellular attachments |
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Term
| Describe the hydrophic changes occurring in cell adaptation and sublethal injury |
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Definition
Usually metabolic disturbance, especially hypoxia - due to failure of pumps and increased osmotic load
Pale, swollen cytoplasm and organelles
Central nucleus |
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Term
| Describe the fatty changes occurring in adaptation and sublethal injury |
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Definition
Ribosomal dysfunction
Lipid and protein metabolism decoupled
Liver - hypoxia, alcohol, diabetes
Micro and macro-vesicular steatosis, initially reversible |
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Term
| Define dystrophic calcification |
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Definition
| Calcification in dead or dying tissues with normal calcium levels. Clinically a sign of previous cell injury. |
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Term
| Describe metastatic calcification |
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Definition
| Deposition of calcium salts in otherwise in normal tissues due to hypercalcaemia, which can occur because of deranged metabolism as well as increased absorption or decreased excretion of calcium and related minerals |
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Term
| Where does metastatic calcification usually occur? |
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Definition
| In skin, gastric mucosa, kidneys, lungs, arteries |
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