Iron Flashcards
65% fo the iron in the body is found as a part of ___
hemoglobin
Sources of Iron
heme iron
non heme iron
Heme iron is derived from
hymoglobin and myoglobin
non heme iron is found in
meat
beans, dark green veg, dried fruit
blackstrap molasses
enriched foods
heme or non heme iron is only found in animal products
heme iron
iron exists in several oxidation states by only two are stable in the body which are;
Fe3+
Fe2+
heme iron is hydrolyzed from hemoglobin and myoglobin in the _____
small intestine
non hem iron is hydrolyzed from food components by HCL and proteases in the
stomach
when heme iron is hydrolyzed in the stomach it releases
Fe3+
FeOH3 which may be complexed from Fe3+ in the SI is relatively (Soluble/insoluble)
insoluble
______ reduces Fe3+ to Fe2+ in the duodenum
ferric reductase
______ is needed as a cofactor for ferric reductase activity
vitamin c
heme iron is absorbed throughout the
small intestine
non heme iron is absorbed via____
DMT1 (divalent mineral transporter 1)
factors that enhance non heme iron absorption
vitamin c
other organic acids (lactic, citric)
meat, fish, poultry
low iron status
_____ strongly enhances the absorption of non heme iron by reducing dietary Fe3+ to Fe2+
vitamin c
factors that inhibit iron absorption
phytic acids polyphenols oxalates Ca Zn Cu Mn nuts soy, wheat, egg, whey tea- peppermint, vervain, linden cham, GT rapid transit time decreased stomach acidity
when iron stores are adequate or high the protein ______ is released from the liver
hepcidin
hepcidin promotes the degradation of _____ which results in decreased transport of iron across basolateral membrane
ferroportin
low levels of hepcidin when iron store are low ______ ferroprotin levels
increase
____ transports iron through the enterocytes
mobilferring
_____ is require for Fe to cross the basolateral membrane
ferroportin
once iron is in the blood it is attached to the protein_____ for transport to other tissues
transferrin
Fe__ leaving the enterocyte must be converted to Fe__
2+
3+
the conversion of Fe2+ to Fe3+ is catalyzed by
hephaestin
ceruloplasmin
the number of transferring receptors expressed by a cell is determined by the amount of:
intracellular ion
iron is primarily stored in the:
liver
the two storage protein forms of iron are
ferritin
hemosiderin
ferritin is the ______ storage protein for iron
primary
ferritin is stable/unstable?
unstable
hemosiderin is a degradation product of
ferritin
hemosiderin levels increase when
iron overload
most plasma iron comes from the degradation of :
hemoglobin
ferritin
hemosiderin
functions of iron
oxygen transport and storage
electron transport and energy metabolism
enzymes
_____ transports oxygen from the lungs to the rest of the body
hemoglobin
____ functions in the transport and short term storage of oxygen in mm cells
myglobin
______ are heme containing compounds that sever as electron carriers during the synthesis of ATP int he mitochondiral ETC
cytochromes
some important iron dependent enzymes
peroxidases
ribonucleotide reductase
tyroside hydroxylase
monooxygenase
iron is primarily excreted in the ____. ____. and ____
blood
bile
desquamated mucosal cells (GIT)
iron deficiency is divided into what three leves
storage iron depletion
early functional iron deficiency
iron deficiency anemia
iron deficiency anemia results when there is inadequate iron to support normal _____ formation
RBC
anemia of iron is characterized as ____ and _____
microcytic
hypochromic
mycrocytic anemia means
RBCs are smaller than normal
hypochromic anemia means
hemoglobin content is decreased = they look pale
sx associated with anemia include
fatigue
tachycardia
arrhythmias
dyspnea
why do the symptoms of anemia such as fatigue, tachycardia, arrhythmias,dyspnea arise
reduced hemoglobin content of RBCs causes decreased oxygen delivery to tissues
other sx of iron deficiency include
cold intolerance
poor concentration, mood disturbances
angular stomatitis, atrophic glossitis
alopecia, brittle- spoon nails
increased risk of iron deficiency in
infants/kids teens menstruating females pregnancy chronic blood loss parasitic infections hypochlorhydria gastric bypass sugery celiac dz vegetarians/vegans regular intense exercise
clinical indications for iron supplementation
restless leg syndrom
adverse effects from iron supplementation include
constipation diarrhea
dark tarry stools
n/v
abd discomfort
iron supplements are better tolerated when taken____
in smaller divided doses with food
there is a high risk for chronic iron toxicity in:
hemochromatosis
thalassemia or sideroblastic anemia
alcoholic cirrhosis
what is hemochromatosis
increase iron absorption in the intestines that result in tissue iron overload
what is hemochromatosis caused by
genetic mutation in the iron absorption proteins
where will iron be deposited in hemochromatosis
joints, liver, heart, pancreas = which will damage these organs = organ failure
treatment of hemochromatosis
freq phlebotomy
_____ enhances absorption of non heme iron
vitamin c
both hephaestin ad cerulopphasmin are ____ dependent enzymes
copper
non hem iron and other divalent minerals such as_______compete for a common absorptive pathway
Ca
Zn
Cu
Mn
iron deficiency increases ____ absorption.
Lead
___ inhibits incorporation of iron int o heme
lead
____ sclera is often associated with iron deficiency
blue
beeturia may also indicate iron____
deficiency
serum ferritin level wil be _____ in early stages of iron deficiency
decreased
MCV may be _____ in iron def
decreased
RDW may be _____ in iron def
increased
