Pathoma: Cell Injury Flashcards
What are the three causes of hypoxia (defined as the decreased O2 delivery to tissues)?
Ischemia (decreased blood flow to organ), hypoxemia (low paO2),
Describe the types of ischemia.
Arterial blockage (narrowing of the arteries) and venous blockage (blocking the flow of fresh blood to organ)
The difference between FiO2, PAO2, PaO2, and SaO2 is _______.
FiO2 = partial pressure of O2 in air; PAO2 = pp of O2 in alveolae; PaO2 = pp of O2 in arteries; and SaO2 = percent saturation of hemoglobin
Anytime the PACO2 increases, the PAO2 ______.
decreases
Define hypoxemia.
(n) a decrease in the partial pressure of oxygen in the blood
Why are those with carbon monoxide poisoning red?
The CO does not dissociate from hemoglobin, thus the hemoglobin remains red throughout the capillaries.
What is one of the first signs of carbon monoxide poisoning?
Headache!
List some oxidant stresses that might induce methemoglobinemia.
Sulfa and nitrate drugs
Classic signs of methemoglobinemia are _______.
cyanosis and chocolate-colored blood
Why does hypoxia injure cells?
Hypoxia leads to decreased ATP synthesis, which itself leads to (1) deficient sodium-potassium pump (water intake, cell swelling); (2) deficient calcium pumps (resulting in increased intracellular calcium, which can activate caspases); and (3) reliance on anerobic metabolism, which creates lactic acid
What are consequence of cell swelling?
Loss of microvilli (due to cell expansion), membrane blebbing (due to membrane swelling off of the cytoskeleton), and RER ribosomes popping off (because the ER also expands with cell swelling)
The hallmark of irreversible cell injury is ________.
membrane damage (this is why so many clinical tests are for intracellular enzymes; if troponin is in the peripheral blood, for example, then it means cardiomyocytes have ruptured)
