Flashcards in LMP301 Lecture 13: Iron & Hemoglobin Deck (62)
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1
Majority of iron comes from...
diet
2
dietary iron is in the form...
ferric
Fe3+
3
Ferric iron is insoluble...
in basic conditions
4
5 - 10% of iron is absorbed at...
the duodenum
5
What happens to iron in the stomach?
- converted to Fe2+
- Fe2+ can be soluble in the basic duodenum, and thus absorbed
6
what increases iron absorption?
- ascorbic acid
- sugars
- AA
7
What decreases iron absorption?
- eggs
- cheese
- milk
- veggies
- tea
8
desquamation
the shedding of epithelial cells
9
Iron is lost through...
- desquamation
- menstrual flow
- urine
10
Iron is stored in...
- RBC (70%)
- Ferritin (20%)
- Myoglobin (5%)
11
Ferritin
intracellular protein that stores iron
12
__ is the transport protein for iron in the plasma
transferrin
13
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
14
(apo)transferrin
transferrin without iron bound to it
15
transferrin has ____ binding sites for ___
2
Fe+++
16
Occupancy of transferrin sites
not always occupied
- only 25-50% of transferrin is normally saturated
17
What used to be an indirect way to measure transferrin concentration?
total iron binding capacity (TIBC)
18
Iron is an ____ element
essential
19
free iron is...
toxic
20
Iron is found complexed with...
- hemoglobin
- myoglobin
- cytochromes
21
binding of iron to proteins occurs though...
heme
22
Heme
- inorganic molecule
- Fe goes in the middle of the ring
23
Iron is stored as...
- ferritin
- hemosiderin
24
Ferritin can bind up to...
4500 iron atoms
This protects cells from free iron damage
25
Hemosiderin
= insoluble ferritin
- release iron slowly
26
1/3 of iron stores are in...
- liver
- spleen
- bone marrow
27
Iron diseases
- iron deficiency (anemia)
- iron overload
- iron poisoning
- chronic disease
28
Iron deficiency is common in...
women, children, elderly
29
Iron deficiency is usually associated with ___ because...
anemia
Iron stores are used up, so can't make enough RBC
30
