Causes Of Cell Injury Flashcards
Define pathogenesis.
The study of the sequence of events from initiation (cause) to conclusion of a disease process.
It is the developmental process of a disease (“who, why, how,and when”).
To understand pathogenesis it is essential to identify the CAUSE and the HOST RESPONSE/TISSUE REACTION and determine the significance.
Define etiology
The study of the cause of disease
What is the mnemonic for Differential Diagnosis?
VINDICATE
What does VINDICATE stand for?
Vascular. Infection, inflammatory, immune-mediated. Neoplasm. Drugs. Iatrogenic. Congenital/developmental/inherited. Anatomic. Trauma. Environmental exposure/endocrine.
What is another mnemonic for Differential Diagnosis?
DAMMIT
What does DAMMIT stand for?
Degenerative. Autoimmune. Metabolic. Nutritional/neoplastic. Inflammatory/idiopathic/iatrogenic. Trauma.
What does cell injury refer to?
Refers to damage or pathologic alterations on molecules and structure that can occur in cells and extra cellular components.
What are some causes of cell injury? List 5.
O2 deprivation. Physical injury. Chemical injury. Infectious agents. Nutritional imbalances. Genetic.
List and define 6 causes/conditions of O2 deprivation.
1) Hypoxia: inadequate oxygenation of tissues.
2) Ischemia: decrease of blood supply in tissues.
3) Anoxia: absence of O2 in tissues.
4) Anemia: decrease in the # of RBC in blood, or decrease in blood volume, or RBC are deficient in hemoglobin.
5) CO2 toxicity.
6) Cyanide toxicosis: due to blockage of cell respiratory enzymes.
What are 5 external agents of physical injury?
Direct mechanical trauma. Temp extremes. Electrical trauma. Radiation. Sudden changes in pressure.
What effect can trauma have on cells?
Direct rupture or death of large #s of cells
Damage to blood supply to cells.
What effect can extreme heat have on cells?
Denatures essential cells enzymes and other proteins.
What effect can excessive heat have on cells?
Can increase the rate of metabolic rxns so that substrates, H2O, and pH changes reach lethal levels.
What effect can electricity have on cells?
Generates great heat as it passes thru tissue.
Alters conduction to nerves and muscles.
Ex.: lightening and high frequency currents.
What effect can ionization radiation have on cells?
Causes ionization of cellular water with production of highly reactive “free radicals”.
What effect can radiation have on cells?
Many forms may damage genetic material producing reproductive cell death of cells, genetic defects, neoplasia.
What effects can extreme cold have?
Impairs blood flow.
Intracellular ice crystals rupture cell membranes.
What are 2 types of radiation and give 3 examples
Radioactive isotope emissions or electromagnetic radiation.
Ex.: UV light, X-ray radiation,cosmic radiation.
What are some class types of chemical, drug, and toxin agents (7) and give some examples of each (# varies).
1) Inorganic poisons: Pb, Cu, arsenic, selenium, Hg, etc.
2) Chemicals: drugs (overdose/idiosyncratic), pesticides, herbicides, rodenticides, etc.
3) Physiologic compounds: Na, Glu, O2, etc.
4) Organic poisons: nitrate/nitrite, oxalate, hydrocyanic acid, etc.
5) Plant toxins: ragwort, sweet clover, braken fern, etc.
6) Animal toxins: snake venom, tick toxin, etc.
7) Mycotoxins: aflatoxin, ergot, fusarium, etc.
What are the 4 biologic/infectious agents discussed (4) and gave some examples.
1) Acellular agents: viruses, prions
2) Prokaryotes: bacteria, chlamydia, rickettsia, mycoplasma
3) Eukaryotes: fungi, protozoa
4) Metazoan parasites: Cestodes, Nematodes, Trematoda, insects
What are some of the effects that viral agents have on cells?
Viruses may cause cell damage by shutting down protein synthesis in host cells and/or by inducing increased membrane permeability and Ca2+ entry.
Viruses can stimulate cytotoxic T-cells that kill infected cells.
Viruses can induce apoptosis.
What effect can bacterial agents have on cells?
Causes variable degree of cell damage depending on type of bacteria.
Bacteria produce toxins: exotoxins, cytotoxins, endotoxins.
Damage could be caused by cytotoxins or inflammatory response.
Give an example as to who can produce an exotoxins and what effect on the cell does it have?
Clostridium spp.
The release of phospholipases can cause membrane damage.
Name 3 spp capable of producing cytotoxins.
Shigella spp.
E. coli
Salmonella spp.
What is produced by Gram- bacteria upon their death that has direct toxic effect on cell membranes?
Lipopolysaccharide (LPS)
The deletion of MURR-1 gene causes what type of disease?
Which dog breed is this derangement seen?
Cu-storage disease that can induce hepatocyte necrosis.
Bedlington terriers.
Cell response to injury depends on 3 criteria:
Type of injury
Duration
Severity
Consequences depend on blank, blank, blank, and blank do the injured cell.
Type
Status
Adaptability
Genetic makeup
For cell injury, the cells are either: 1) 2) 3) 4) That affect essential cellular constituents.
1) Exposed to persistent stress beyond the limits of adaptive responses.
2) Exposed to injurious stimuli.
3) Deprived of essential nutrients.
4) Compromised by mutations.
What are the 4 interrelated cell systems that are particularly vulnerable to injury?
1) Membranes (cellular and organellular).
2) Aerobic respiration.
3) Protein synthesis (enzymes, structural proteins, etc.).
4) Genetic apparatus (eg DNA, RNA)
