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31 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Iron functions in body
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DNA synth
electron transport drug, steroid, FA metabolism Nucleotide metab TCA Cycle |
energy & DNA
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properties of iron
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oxidation/reduction
not soluble at phys pH free radical damage (from hydoroxyl radicals OH-) |
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most soluble form of iron
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Fe 2+ & heme
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location & function of DMT1
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membrane enterocytes
transport in from lumen |
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location & function of ferroportin
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membrane intestine & MPs
transport iron out |
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location & function of transferrin
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serum (synthed in liver)
chaperone iron in circ |
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location & function transferrin receptor
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plasma membrane tissues
internalization of FE-TF |
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function of hepcidin
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serum
synthed in liver regulates export from cells elevated in inflammation & infection |
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iron protein elevated in infection/inflammation
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hepcidin
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location & function of ferritin
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cytoplasm of all cells
storage of iron |
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location & function of IRE-BP
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cytoplasm of all cells
regulates production of transferrin & ferritin |
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major locations of iron in normal body
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hemeglobin
ferritin tissue enzymes (myglobin, transferrin & serum ferritin are low) |
3
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how much iron can get absorbed from diet
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typically 10%
can increase to 30% b/c IREBP 1-2 mg/day (lose ~ 1-2 mg/d) |
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intestinal role in iron homeostasis
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crypt cells regulate Fe absorption
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Liver role in Fe homeostasis
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up/downreg proteins
storage regulate traffic |
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uptake of Fe at crypt cells
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Fe3 in diet
mucin holds near crypt cell ferroreductase gives Fe2 DMT into cell chaperoned (unknown) store, use or out ferroportin transport out Hephaestin oxidizes back to Fe3 picked up by transferrin |
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Fe uptake in tissues
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FeTf binds TfR
endocytosed H+ pump (in) changes pH iron released transprter & transferrin recycled |
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regulation of iron intake at tissues
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regulated by increase/decrease # of receptors
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protein for regulation of iron intake
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IREBP
Fe not bound: IREBP active - prevent transferrin degredation (5') - inhibit translation of ferritin (5') |
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dietary factors increasing Fe absorption
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aa's, ascorbic acid (C), citrate, organic acids
complex with Fe for uptake |
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dietary factors decreasing Fe absorption
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phytates
oxalates (spinach) tannin phosphate |
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function of TfR2
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sensor in liver for iron homeostasis
high liver iron increases Hepcidin hepcidin internalizes ferroportin (no Fe return to bloodstream or absorb) |
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function of hepcidin
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when liver Fe high
internalizes ferroportin decrease intest intake & MP release (Less Fe in tissues) increased by IL-6 |
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mechanism of anemia of infection
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IL-6 increases hepcidin
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causes of iron overload
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numerous transfusions (thallasemias)
hemachromatosis- auto rec, mut (C282Y) in HFE, regulates hepcidin expression mutation of hepcidin |
3
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assessment of iron status
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RBC indices
Serum ferritin (best indicator) transferrin sat serum transferrin serum iron (least useful) |
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RBC indices
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MCV
MCH MCHC RDW |
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microcytic, hypochromic, low iron, high TIBC, low sat, low stores
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iron def anemia
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normal cells, low iron, low TIBC, low sat, normal stores
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anemia of inflammation
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increased serum ferritin, and transferrin saturation
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hemachromacytosis
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stages of iron deficient anemia
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I- iron deplet
II- iron def erythpo III- Iron def anemia iron stores fall, then transferrin sat, then circulating Fe & Hgb (affects RBC indices) |
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