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40 Cards in this Set
- Front
- Back
What is the most common cause of an elevated homocysteine level?
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Folate deficiency
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What are some extopic sources of epo?
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renal cell carcinoma, hepatocellular carcinoma
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where is epo synthesized?
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the endothelial cells of the peritubular capillaries
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What is the retic count?
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measure of effective erythropoesis to compensate for anemia, hct/45%
more than 3% good, less than 3% not good |
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Where does extra medullary hematopoesis most frequently occur?
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liver and spleen
occurs with myelofibrosis, or with accelerated destruction of RBCs (hemolytic anemia--> may expand the bone marrow) |
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What is HbF, and what does it do to the oxygen binding curve?
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HbF is two alpha and two gamma chains, shifts the curve to the left (takes oxygen) -- this causes a release of epo
epo increases RBC, Hct and HGb |
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Why are newborns jaundiced?
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the HgF is destroyed by splenic macrophages over the ensuing 6-9 months, the unconjugated bilirubin derived from the initial destruction is responsible for the physiologic jaundice
the HgF are replaced by HgA (97%), HgA2 (2.5%) and HbF (1) |
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What are the changes in RBC counts with thalassemia?
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Decreased Hct and Hgb, Increased RBC count
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Hypochromasia
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Central Area of pallor on the Red Blood Cells, corresponds with a decreased Hg (microcytic anemia)
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Iron Deficiency Anemia
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increased RDW
decreased ferritin (diagnostic of iron deficiency), decreased percent saturation, INCREASED transferrin |
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serum ferritin
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Diagnostic of Iron Deficiency (low levels)
ferritin is the primary soluble iron storage protein, seen in bone marrow macrophages macrophages synthesis ferritin increases with inflammation due to IL-1 and TNF alpha stored in bone marrow macrophages-- the serum levels of ferritin correlate with the level stored in |
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What has increased serum ferritin levels?
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anemia of chronic disease and iron overload
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what is hemosiderin?
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insoluble degradation product of ferritin, the levels correlate with ferritin levels
Iron Deficiency: decreased ferritin, decreased hemosiderin ACD and Iron Overload: increased ferritin, increased hemosiderin |
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serum iron levels
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Iron bound to transferrin, the iron binding protein
transferrin is synthesized in the liver-- normal serum iron is 100ug/dL |
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Decreased Serum Iron
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Seen in Iron Deficiency and ACD
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What is the relationship between ferritin and transferrin levels?
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decreased ferritin stores causes increased synthesis of transferrin
see increased transferrin levels in iron deficiency and anemia of chronic disease |
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What is needed to make ALA?
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ALA synthase, Glycine and Vitamin B6
this occurs in the mitochondria |
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What is needed to make heme?
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Iron plus protoporphyrin along with the enzyme ferrochetalase
this occurs in the mitochondria |
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what does iron deficiency look like?
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decreased iron, decreased ferritin, decreased percent saturation, INCREASED transferrin level and RDW
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What would chronic alcholism do to a blood smear?
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Alcohol is a mitochondrial toxin, damamges heme biosynthesis pathways, causing sideroblastic anemia
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pyridoxine deficiency
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this is VB6; you need it as a cofactor to make ALA as a cofactor for ALA synthase, the rate limiting step in heme synthesis
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Thalassemia
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Autosomal Recessive
alpha thal- SE asians and blacks beta thal: americans, greeks and italians |
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what is the pathogenesis of alpha thal?
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gene deletions; there is a decrease in alpha golbin chain synthesis due to gene deletions of the 4 that control alpha globin synthesis
1 deletion: SILENT 2: alpha thal trait mild anemia with increased RBC count, decreased HbA, HbA2, HbF (normal electrophoresis bc all Hg require alpha chains, proportion is the same) --> no treatment 3 deletions: HbH the four beta chain disease--> severe hemolytic anemia, electrophoresis detects HgH 4 deletion: Hb Barts-- no life |
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what is the pathogenesis of beta thal?
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mild: it's a splicing defect
severe: stop codon |
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release reaction
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when the platelet sticks, it releases chemicals (ADP and Thromboxane A2)
platelet is the ONLY cell that can make TXA2 |
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Functions of TXA2
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potent vasoconstrictor (what causes prinzemetal angina coronary spasm)
causes platelet sticking bronchoconstrictor |
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Mast Cells preformed chemicals
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histamine
esosinophilic chemotactic factor serotonin later on, releases prostaglandins and leukotrienes to enhance the inflammatory mediators |
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thrombocytopenia
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less than 90,000 platelets
vWF (most common genetic AD--1 in 250) have it taking aspirin causes prolonged BT |
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Aspirin
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Endothelial cells have COX, but aspirin doesn't inhibit this. The platelet COX is a different compound
9 times greater inhibition of platelet COX than the endothelial COX |
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Thrombin
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converts fibrinogen into fibrin
thrombin is generated by the coagulation pathway-- and will convert the unstable plug into something more stable |
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plasminogen
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will break up the clot
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platelet abnormalities
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petechia, prolonged BT, ecchymosis, epistaxis (nose bleeds)
NONE of these occur in a coagulation deficiency |
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Hemophilia
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has problems with LATE bleeding
after an appendectomy-- the platelet plugs are only temporary if you don't have any problems after a wisdom tooth extraction, you've had no problems with coagulation |
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bleeding time
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normal is about 7-9 minutes
cut vessel, release tissue thromboplastin (later activates extrinsic pathway) expose collagen activates (12, intrinsic) endothelial cells and megakarocytes make vwF (a part of factor VIII) so platelets carry some glue with them, vwF is also made in the endothelial cells, damaged endothelial cells, vWF is exposed. vwF is exposed so that platelets can stick, and releases chemicals, ADP a POTENT aggregator, along with Thromboxane A2, which ends the bleeding time. clot formed |
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ADP
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potent aggregator released by platelets
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Thromboxane Synthase
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only in platelets-- PGH2--> TXA2
TXA2 is a potent vasoconstrictor which helps platelets to stick. TXA2 causes the prinzmetal angina in coronary artery spasm. It's also a bronchoconstrictor. |
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Platelet Plug
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temporary plug, held together by fibrinogen. Enough to prevent bleeding, but it's not stable
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Prolonged bleeding time
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Thrombocytopenia-- less than 90,000
Taking Aspirin (blocks platelet COX) vwF deficiency: 1 in 250 people have this |
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aspirin
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taking one, NONE of your platelets will work, no TXA2 around, no aggregating
bleeding time is around 15-20 minutes |
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Who removes the platelet plug?
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plasminogen
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