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33 terms

General Pathology - Causes of Cell Injury

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With regards to differential diagnosis, what does VINDICATE mean?
- Vascular
- Infection/ Inflammatory/ Immune-mediated
- neoplasm
- Drugs
- Iatrogenic
- Congenital/ Developmental/ Inherited
- Anatomic
- Trauma
- Environmental Exposure/ Endocrine
What is cell injury?
damage or pathologic alterations in molecules and structure that can occur in cells and extracellular components
What 4 things can cause injury?
- persistent stress
- injurious stimuli
- deprived of essential nutrients
- compromised by mutations
When heart muscle accumulates fat droplets, is this the reversible or irreversible stage?
- reversible
What 4 cell systems are particularly vulnerable to injury?
- membranes
- aerobic respiration
- protein synthesis
- genetic apparatus (DNA, RNA)
What is ischemia?
reduced blood flow to the organ or part of the body
What is hypoxia?
inadequate oxygenation of tissues
what is anoxia?
complete loss of oxygen in the tissues
What is anemia?
decreased number of red blood cells in blood or volume or are deficient in hemoglbin
What are the 6 causes of oxygen deprivation?
- hypoxia
- ischemia
- anoxia
- anemia
- CO2 toxicity
- cyanide toxicosis
What is the pathogenesis of cyanide toxicosis?
- plants containing cyanogenic glycosides yield free hydrocyanic acid when hydrolyzed or plant cell structure is disrupted
- cyanide is absorbed and reacts with Fe3+ in cytochrome oxidase= stops cellular respirationvia oxygen deprivation bc the oxyhemoglobin cannot release O2
What type of physical agent causes direct rupture or death of large #s of cells and damage to blood supply to cells?
trauma
What type of physical agent denatures essential cell enzymes and other proteins?
extreme heat
What type of physical agent can increase the rate of metabolic reactions so that substrates, H2O, and pH changes reach lethal levels?
excessive heat
What type of physical agent generates great heat at it passes through tissue and alters conduction to nerves and muscles?
electricity
What type of physical agent causes ionization of cellular water with production of highly reactive free radicals?
Ionization radiation
What type of physical agent damages genetic material producing reproductive cell death of cells, genetic defects, and neoplasia?
radiation
How does extreme cold cause cell injury?
- impairs blood flow
- intracellular ice crystals rupture cell membranes
What does lead poisoning cause?
neuronal necrosis and renal tubular necrosis
What is type of toxin does not need to be converted to cause toxicity?
direct toxin
What type of toxin must be converted into another molecule to have a toxic affect?
indirect toxin
What is an exotoxin?
toxin secreted by gram positive bacterial that causes membrane damage
what is an endotoxin?
toxin (LPS) secreted by gram-negative bacteria from their walls upon cell death
- toxic to membranes
Endotoxin induced damage to endothelial cells activates what response in the host?
- coagulation pathway
- complement system
- results in inflammatory reaction and cell injury
What effect do endotoxins have on macrophages?
- activates them to release cytokines:
- TNF-alpha
What does TNF-alpha induce?
apoptosis
How do viruses act to kill cells?
- shuts down host cell protein synthesis
- inc. membrane permeability of Ca entry
- stimulates cytoxic Tcells taht kill infected cells via FAS-FAS ligand
- induce apoptosis
Vitamin E deficiency causes what in pigs?
hepatocellular necrosis
High dietary copper causes what in sheep?
hemolysis of redblood cells
Why does too much copper cause hepatocyte necrosis in bedlington terrier dogs?
- deletion of MURR1 gene cause them not to be able to get rid of copper
What is premature loss of vitality or degeneration of cells or tissues, especially when due to genetic causes?
abiotrophy
What does cellular response to an injurious stimuli depend on?
type, duration, and severity of the injury
What is cell death the result of?
irreversible cell injury