HEMA Lec - Chapter 11 Flashcards
Body iron content:
3-4 g
iron compartments 70%
Hb
iron compartments 25%
storage iron: ferritin & hemosiderin
iron compartments 5%
myoglobin
iron compartments
POD, Catalase
Cytochrome
Fiboflavin enzymes
Transferrin
iron compartments 0.1%
serum
Iron overload: due to
- increased Fe absorption due to genetic predisposition 2. repeated transfusion
Iron deficiency
Excessive bleeding
Inadequate intake
Thus iron homeostasis is regulated by ____
adjusting iron intake
mg iron are absorbed each day
1 – 2 mg
iron absorption occurs where
duodenum and jejunum
should be the form of iron so that it will enter the cell (enterocyte)
Fe +2 :
sources of
Heme: Non-heme: from legumes, leafy veggies
from Hb; Mb and meat sources;
sources of
Non-heme:
from legumes, leafy veggies
Only?%of dietary iron absorbed
10%
how is iron lost in the body [physiologic]
Cell loss: gut, desquamation
Menstruation (1mg/day)
Pregnancy, lactation
Reduction Fe+++ to Fe++
DcytB (for non-heme iron)
Transport into cell for non-heme iron
DMT1 (for non heme iron)
Transport out Fe+2
Ferroportin
Oxidizes Fe++ to Fe+++
Hephaestin
: acted upon by heme oxygenase to free Fe+2
Hemin
hepcidin meaning
Hepatic bacteriocidal protein
Master iron regulatory hormone
hepcidin
Inactivates ferroportin
hepcidin
Stops iron getting out of gut cells
Iron lost in stool when gut cells shed
hepcidin
Leads to decreased gut iron absorption
hepcidin
decrease in stored iron in the macrophages and liver
hepcidin
present on cell surface to release iron
Found on gut cells, liver cells and macrophages
Ferroportin
TRANSFERRIN synthesized in ___
liver
cofactors required by ferroportin
to oxidize iron to allow for binding to transferrin
Hephaestin in gut
Ceruloplasmin in other cells
Transferrin gene is located in chromosome ____
3(long arm)
Each molecule of transferrin binds can bind ___ Fe3+ molecules (oxidized)
2
saturation of transferrin with Fe
30%
Transferrin Contains __% of serum Fe.
95%
Truncated form of cell surface receptors
Found in the circulation
Soluble Transferrin Receptors
3 STORAGE SITES OF IRON
Liver
BM
Spleen
high level of soluble transferrin receptors would mean iron deficiency or overload
deficiency
= iron-binding sites w/c do not carry iron
Serum unsaturated iron-binding capacity
ferritin binding up __ atoms of iron per molecule.
4,500
A routine blood test – reflects iron stores
Ferritin
Prussian blue can be used to stain (blue coloration) [3]
hemosiderin, siderocyte and sideroblasts
retic in the BM with iron
Siderocytes
normal is only 10%; these are the nucleated RBCs in the BM w/ iron
Sideroblasts
Normally , mature RBCs must or must not contain iron?
must not
