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31 Cards in this Set

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Iron functions in body
DNA synth
electron transport
drug, steroid, FA metabolism
Nucleotide metab
TCA Cycle
energy & DNA
properties of iron
oxidation/reduction
not soluble at phys pH
free radical damage (from hydoroxyl radicals OH-)
most soluble form of iron
Fe 2+ & heme
location & function of DMT1
membrane enterocytes
transport in from lumen
location & function of ferroportin
membrane intestine & MPs
transport iron out
location & function of transferrin
serum (synthed in liver)
chaperone iron in circ
location & function transferrin receptor
plasma membrane tissues
internalization of FE-TF
function of hepcidin
serum
synthed in liver
regulates export from cells
elevated in inflammation & infection
iron protein elevated in infection/inflammation
hepcidin
location & function of ferritin
cytoplasm of all cells
storage of iron
location & function of IRE-BP
cytoplasm of all cells
regulates production of transferrin & ferritin
major locations of iron in normal body
hemeglobin
ferritin
tissue enzymes
(myglobin, transferrin & serum ferritin are low)
3
how much iron can get absorbed from diet
typically 10%
can increase to 30% b/c IREBP
1-2 mg/day (lose ~ 1-2 mg/d)
intestinal role in iron homeostasis
crypt cells regulate Fe absorption
Liver role in Fe homeostasis
up/downreg proteins
storage
regulate traffic
uptake of Fe at crypt cells
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
Fe uptake in tissues
FeTf binds TfR
endocytosed
H+ pump (in) changes pH
iron released
transprter & transferrin recycled
regulation of iron intake at tissues
regulated by increase/decrease # of receptors
protein for regulation of iron intake
IREBP
Fe not bound: IREBP active
- prevent transferrin degredation (5')
- inhibit translation of ferritin (5')
dietary factors increasing Fe absorption
aa's, ascorbic acid (C), citrate, organic acids

complex with Fe for uptake
dietary factors decreasing Fe absorption
phytates
oxalates (spinach)
tannin
phosphate
function of TfR2
sensor in liver for iron homeostasis
high liver iron increases Hepcidin
hepcidin internalizes ferroportin (no Fe return to bloodstream or absorb)
function of hepcidin
when liver Fe high
internalizes ferroportin
decrease intest intake & MP release
(Less Fe in tissues)
increased by IL-6
mechanism of anemia of infection
IL-6 increases hepcidin
causes of iron overload
numerous transfusions (thallasemias)
hemachromatosis- auto rec, mut (C282Y) in HFE, regulates hepcidin expression
mutation of hepcidin
3
assessment of iron status
RBC indices
Serum ferritin (best indicator)
transferrin sat
serum transferrin
serum iron (least useful)
RBC indices
MCV
MCH
MCHC
RDW
microcytic, hypochromic, low iron, high TIBC, low sat, low stores
iron def anemia
normal cells, low iron, low TIBC, low sat, normal stores
anemia of inflammation
increased serum ferritin, and transferrin saturation
hemachromacytosis
stages of iron deficient anemia
I- iron deplet
II- iron def erythpo
III- Iron def anemia

iron stores fall, then transferrin sat, then circulating Fe & Hgb (affects RBC indices)