Clin Path-Erythrophysiology.txt

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Clin Path-Erythrophysiology.txt
2014-09-29 20:59:38
vet med
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  1. What are the components of the RBC membrane and cytoplasm
    • Membrane- fatty acids and cholesterol, including glycolipids and glycoproteins.
    • Cytoplasm- contains hemoglobin; in mammals, lacks nuclei, mitochondria, and ribosomes; in non-mammals, retains nucleus.
  2. How do RBCs respond to tissue hypoxia?
    tissue hypoxia stimulates increased EPO production, causing increased erythropoiesis, which increases transport of oxygen to tissues; can be assessed by reticulocyte count, but reticulocytosis is not apparent in peripheral blood for 2-3 days; they also release nRBC into circulation (may also be attributed to EMH or BM disease )
  3. Compare the reticulocyte response in cats, dogs, cattle, and horses.
    cattle do not release as many reticulocytes than cats and dogs with increased erythropoiesis; horses do not release reticulocytes into circulation.
  4. What two pathways do RBCs use to metabolize glucose?
    Embden-Meyerhof Pathway and Pentose Phosphate Pathway
  5. Name 2 clinical syndromes associated with abnormalities in the Embden-Meyerhof Pathway.
    PFK (phosphofructokinase) deficiency in Springer Spaniels and Whippets and PK (pyruvate kinase) deficiency in basenjis, beagles, and westies (HEMOLYTIC ANEMIA)
  6. What clinical manifestations are associated with abnormalities in the Pentose Phosphate Pathway?
    hemolytic anemia with formation of heinz bodies and/or eccentrocytes
  7. What are the major functions of RBCs?
    to carry oxygen to the tissues,to carry CO2 to the lungs
  8. Describe the crux of hemoglobin synthesis.
    it is a very complicated process that takes place in the cytoplasm and mitochondria of RBC precursors; the intact heme is manufactured in the cytoplasm; globin polypeptides are synthesized on ribosomes in the cytoplasm.
  9. MetHb forms when the Fe in Hb is ______ from _____ to _____; this form cannot....
    oxidized from Fe2+ to Fe3+; bind O2
  10. In healthy animals MetHb is addressed by the function of ______; abnormalities in this process cause...
    MetHb reductase; mild exercise intolerance, intermittent lethargy, and increased risk associated with anesthesia.
  11. Cross-linking of ________ in globin portion of Hb causes the formation of ______, which are associated with _____.
    SH groups; Heinz bodies; hemolytic anemia
  12. Oxidative damage to the RBC membrane causing adhesion of opposing areas of the cytoplasmic face of the membrane is known as _______, which makes animals susceptible to ____.
    eccentrocytes; splenic trapping
  13. How are senescent RBCs removed from circulation?
    they are phagocytized and degraded by macrophages in the spleen and liver
  14. When Hb is metabolized by macrophages, it dissociates into _____________, which then go to...
    heme and globulin chains; globulin is reused; heme is oxidized to biliverdin and Fe by heme oxygenase
  15. Biliverdin is metabolized to ____ and is transported out of the macrophage by ____.
    unconjugated bilirubin; biliverdin reductase
  16. Fe product of Hb metabolism is transported by _____ and stored as _____ in the tissues.
    transferrin; hemmosiderin (ferritin)
  17. Unconjugated bilirubin binds to _______ for transport to the _____, where it is metabolized to conjugated bilirubin.
    albumin; liver
  18. _______ conjugate unconjugated bilirubin.
  19. In the large intestine, conjugated bilirubin is converted to _________ and then to _________, which is mostly secreted in feces or urine.
    urobilinogen; stercobilinogen
  20. Hyperbilirubinemia is indicative of... (3)
    hemolysis (pre-hepatic), liver disease (hepatic), or obstruction of bile flow (post-hepatic)
  21. Pre-hepatic bilirubinemia occurs with _______ and has the following 4 clinical manifestations on a CBC and blood smear....
    hemolysis; decrease PVC, sphereocyte, heinz bodies, and hemotrophic parasites
  22. Hepatic bilirubinemia occurs from _____ and is associated with the following 5 liver disorders.....
    inability to take up or excrete bilirubin; lipidosis, cirrhosis, inflammation, neoplasia,or genetic defects
  23. Post-hepatic hyperbilirubinemia occurs with ___________ and is most often due to one of the 3 following disorders...
    obstruction of bile from cholestasis; pancreatitis, cholangitis, or neoplasia
  24. What test is used to quantify unconjugated and conjugated bilirubin?
    The Van den Bergh test
  25. What differential usually accounts for hyperbilirubinemia in horses?
  26. What disorder of heme synthesis is often indicated by basophilic stippling?
    Lead toxicity
  27. Disorder of heme synthesis characterized by excessive porphyrin production and accumulation in the teeth, bones, gums, and skin.
    congenital porphyria
  28. The majority of iron is in ___.
  29. Almost all Fe is obtained by _____.
    recycling senescent RBCs
  30. __________ cells regulate Fe absorption
    Intestinal epithelial cells
  31. Plasma protein that binds Fe3+ for transport to tissues.
  32. Fe deficiency in veterinary medicine is almost always due to _____.
    chronic blood loss
  33. Iron is stored in... (3) as _____ or _____.
    liver, spleen, and BM; ferritin or hemosiderin
  34. Once absorbed, the only mechanism of Fe excretion is _______.
    sloughing of intestinal epithelial cells
  35. Hepcidin is synthesized in the ______ and is a regulator of ______
    liver; iron metabolism (inhibits dietary absorption)
  36. Hepcidin is down-regulated by _________ and up-regulated by _________.
    anemia or hypoxia (so more iron is absorbed); inflammation (more iron is stored in macrophages).
  37. The oxyhemoglobin dissociation curve is ______, indicating that....
    sigmoidal; binding of the first heme binding to O2 allows easier binding of subsequent O2 molecules.
  38. Describe the conditions in tissues and what the result is on the oxyhemoglobin dissociation curve.
    low pH, high 2,3-DPG, high temp, and high CO2; there is a right shift so oxygen is readily released from heme to the tissues
  39. Describe the conditions in the lungs and what the result is on the oxyhemoglobin dissociation curve.
    high pH, low 2,3-DPG, low temp, and low CO2; left shift to increase affinity of heme and O2 to facilitate transport of O2 to the tissues
  40. Fetal Hb has _____ O2 affinity, indicated by a _____ shift.
    higher; left
  41. When 2,3-DPG associates with Hb, the oxyhemoglobin dissociation curve shift to the _____ allowing....
    right; increased unloading of O2 in the tissues.
  42. 2,3-DPG levels increase when...
    there is higher tissue demand for O2 or less O2 available