Flashcards in Iron in Disease Deck (115)
What 2 things is iron essential for?
* Iron transport
* Electron transport
In iron, there is reversible/irreversible O2 binding from Hb
What 3 things is iron present in?
* Enzymes e.g. cytochromes.
Why is iron dangerous?
Due to its chemical reactivity - oxidative stress
Because iron can be toxic to the body, what does the body do to prevent this?
* Safe transport.
* Safe storage.
* Regulation of iron absorption.
Iron does NOT have a ....
Mechanism of excretion
Iron does NOT have a mechanism of excretion
What is there in each globin chain?
1 haem group
What ion is found in each haem group of every globin chain?
Where does the Fe2+ ion in the haem group sit?
In the porphyrin ring
Where is the majority of body iron found?
How is haem formed?
Protoporphyrin is formed from porphobilinogen
This combines with Fe3+ to form haem.
Porphyrin ring + Fe2+ =
How much iron does the body absorb per day?
1mg / day
How much iron exists in:
ii) parenchymal tissues
iii) erythroid marrow
iv) red cell haemoglobin
v) macrophage stores?
How much iron is lost per day?
Where does iron absorption occur?
In the duodenum
Iron absorption occurs in the _________
What is responsible for the transport of IRON INTO the DUODENAL ENTEROCYTE?
DMT (Divalent metal transporter) -1
What is the role of FERROPORTIN?
Facilitates iron EXPORT from the enterocyte
What happens to iron once it has been exported from he enterocyte?
It is passed on to transferrin for transport elsewhere
What is responsible for the down-regulation of ferroportin?
What does hepcidin do?
Down-regulates ferroportin to decrease exportation of iron from the enterocyte
The regulation of iron absorption can be grouped into 3 factors, what are these?
1. Intra-luminal factors.
2. Mucosal factors.
3. Systemic factors.
What does intraluminal factors for regulation of iron absorption take into account?
* Solubility of inorganic iron.
* Haem iron is easier to absorb.
* The reduction of (Fe3+) to ferrous (Fe2+)
What does mucosal factors refer to?
The expression of iron transporters
Give examples of 2 iron transporters (used in the regulation of iron absorption).
* DMT-1 (divalent metal transporter) - at mucosal surface.
* Ferroportin - at serosal surface.