LMP301 Lecture 13: Iron & Hemoglobin Flashcards Preview

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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

causes of iron deficiency

- loss of blood
- inadequate intake