Flashcards in LMP301 Lecture 13: Iron & Hemoglobin Deck (62)
Majority of iron comes from...
dietary iron is in the form...
Ferric iron is insoluble...
in basic conditions
5 - 10% of iron is absorbed at...
What happens to iron in the stomach?
- converted to Fe2+
- Fe2+ can be soluble in the basic duodenum, and thus absorbed
what increases iron absorption?
- ascorbic acid
What decreases iron absorption?
the shedding of epithelial cells
Iron is lost through...
- menstrual flow
Iron is stored in...
- RBC (70%)
- Ferritin (20%)
- Myoglobin (5%)
intracellular protein that stores iron
__ is the transport protein for iron in the plasma
Process of iron uptake into cells
1. transferrin receptor binds transferrin holding iron
2. endosome engulfs
3. endosome pH changes to acidic
4. iron is released from transferrin, and is pumped out of endosome
5. (apo)transferrin-receptor is recycled
transferrin without iron bound to it
transferrin has ____ binding sites for ___
Occupancy of transferrin sites
not always occupied
- only 25-50% of transferrin is normally saturated
What used to be an indirect way to measure transferrin concentration?
total iron binding capacity (TIBC)
Iron is an ____ element
free iron is...
Iron is found complexed with...
binding of iron to proteins occurs though...
- inorganic molecule
- Fe goes in the middle of the ring
Iron is stored as...
Ferritin can bind up to...
4500 iron atoms
This protects cells from free iron damage
= insoluble ferritin
- release iron slowly
1/3 of iron stores are in...
- bone marrow
- iron deficiency (anemia)
- iron overload
- iron poisoning
- chronic disease
Iron deficiency is common in...
women, children, elderly
Iron deficiency is usually associated with ___ because...
Iron stores are used up, so can't make enough RBC