Causes of cell injury

• Hypoxia, ischemia

  • brain; heart: atherosclerosis, a process that advances as you get older

• Nutrition

  • too little (developing countries) or too much (developed countries)

• Genetic disease

  • sickle-cell disease, the molecular basis of which was defined when Dr. Baird was in medical school

  • Tay-Sachs, for which screening can now be performed

  • Gaucher’s disease, of which there are three different forms

Ischemic changes in cells

• Ca leaks into cells, uncoupling ox phos and causing further damage

• you basically need to know it at the level of this diagram, which is found in the book

• leukocyte recruitment further damages cells because leukocytes excrete hyperactive oxygen radicals

• Physical agents

  • heat

  • cold

  • bullets

  • sports

• Infections agents

  • viruses

  • bacteria

  • fungi

  • prions, which are alternative folding patterns of proteins

• Autoimmunity

  • antibodies

    • autoimmune hemolytic anemia

    • erythroblastosis fetalis: Rh antigen and maternal anti-Rh, anti-fetus antibodies

    • lupus erythematosus: antibodies against DNA; potential exposure was in bone marrow (10% of RBCs are defective and are turned over; nuclear material leaks out)

  • T cells

    • involved in graft rejection

    • also play a role in polio, where most of the destruction of neurons is via the polio virus; however, if T cells are turned on, they kill the virus-producing factories—namely, the neurons, which can’t regenerate

    • hepatitis B: hepatocytes are destroyed

Category: Medical Subject Notes , Pathology Notes