HEMA Lec - Chapter 11 Flashcards Preview

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Flashcards in HEMA Lec - Chapter 11 Deck (44):
1

Body iron content:

3-4 g

2

iron compartments 70%

Hb

3

iron compartments 25%

storage iron: ferritin & hemosiderin

4

iron compartments 5%

myoglobin

5

iron compartments

POD, Catalase
Cytochrome
Fiboflavin enzymes
Transferrin

6

iron compartments 0.1%

serum

7

Iron overload: due to

1. increased Fe absorption due to genetic predisposition 2. repeated transfusion

8

Iron deficiency

Excessive bleeding
Inadequate intake

9

Thus iron homeostasis is regulated by ____

adjusting iron intake

10

mg iron are absorbed each day

1 – 2 mg

11

iron absorption occurs where

duodenum and jejunum

12

should be the form of iron so that it will enter the cell (enterocyte)

Fe +2 :

13

sources of
Heme: Non-heme: from legumes, leafy veggies

from Hb; Mb and meat sources;

14

sources of
Non-heme:

from legumes, leafy veggies

15

Only?%of dietary iron absorbed

10%

16

how is iron lost in the body [physiologic]

Cell loss: gut, desquamation
Menstruation (1mg/day)
Pregnancy, lactation

17


Reduction Fe+++ to Fe++




DcytB (for non-heme iron)

18

Transport into cell for non-heme iron

DMT1 (for non heme iron)

19


Transport out Fe+2

Ferroportin

20


Oxidizes Fe++ to Fe+++

Hephaestin

21

: acted upon by heme oxygenase to free Fe+2

Hemin

22

hepcidin meaning

Hepatic bacteriocidal protein


23

Master iron regulatory hormone

hepcidin

24

Inactivates ferroportin

hepcidin

25

Stops iron getting out of gut cells
Iron lost in stool when gut cells shed

hepcidin

26

Leads to decreased gut iron absorption

hepcidin

27

decrease in stored iron in the macrophages and liver

hepcidin

28


present on cell surface to release iron
Found on gut cells, liver cells and macrophages

Ferroportin

29

TRANSFERRIN synthesized in ___

liver

30

cofactors required by ferroportin
to oxidize iron to allow for binding to transferrin

Hephaestin in gut
Ceruloplasmin in other cells

31


Transferrin gene is located in chromosome ____

3(long arm)

32

Each molecule of transferrin binds can bind ___ Fe3+ molecules (oxidized)

2

33

saturation of transferrin with Fe

30%

34

Transferrin Contains __% of serum Fe.

95%

35

Truncated form of cell surface receptors
Found in the circulation

Soluble Transferrin Receptors

36

3 STORAGE SITES OF IRON

Liver
BM
Spleen

37

high level of soluble transferrin receptors would mean iron deficiency or overload

deficiency

38


= iron-binding sites w/c do not carry iron

Serum unsaturated iron-binding capacity

39

ferritin binding up __ atoms of iron per molecule.

4,500

40

A routine blood test – reflects iron stores

Ferritin

41

Prussian blue can be used to stain (blue coloration) [3]

hemosiderin, siderocyte and sideroblasts

42

retic in the BM with iron

Siderocytes

43

normal is only 10%; these are the nucleated RBCs in the BM w/ iron

Sideroblasts

44

Normally , mature RBCs must or must not contain iron?

must not

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