Iron absorption Flashcards Preview

COM Anatomy, Biochemistry, OS > Iron absorption > Flashcards

Flashcards in Iron absorption Deck (20):
1

HFE

mutation responsible for most common absorption problems hemochromatosis

chromosome 6

protein HFE

2

HJV

mutation responsible for jeuvanile absorption problems

protein Hemojeuvelin

chromosome 1

3

TFR2

mutation responsible for clinically similar features to HFE but rare

chromosome 7

protein Transferrin receptor 2

4

SLC40A1

chromosome 2

protein ferroportin

5

HAMP

hepcidin, an iron regulation hormone critical for absorption

chromosome 19

6

factors that INCREASE iron absorption

inadequate diet
impaired absorption
celiac disease
GI bleeding
hypoxia
anemias
decreased erythropoiesis

7

factors decreasing iron absorption

regular blood transfusions
high iron diet
iron loading vitamins

8

human hemochromatosis protein

HFE

functions to regulate circulating iron uptake by regulating the interaction of the TFR 1/2 with transferrin


9

Hepcidin

key regulator of the entry of iron into circulation

10

transferrin

iron binding blood plasma glycoprotein that controls the level of free iron in biological fluids

11

TFR1

a protein required for iron imort from transferrin into cells by endocytosis

12

TFR2

protein involved in uptake of transferrin bound iron into cells by endocytosis, although role is minor compared to TFR1

13

Ferroportin

transmembrane protein that transports iron from the inside of the cell to the outside of the cell. inhabited by hepcidin, results in the retention of iron

14

Low iron and Hepcidin

low iron decreases hepcidin, which causes ferroportin to ne expressed in order to allow iron to be absorbed by the duodenum

15

High iron and hepcidin

high iron causes hepcidin to be high, which causes ferroportin to be prevented from bringing more iron in from the duodenum and gut

16

hepcidin expression is regulated by

HFE, HJV, TRF2

17

mutation ins HFE, HJV and TRF2 effect

hepcidin expression, which regulates iron absorption

18

Transferrin binds two molecules

TRF and HFE

Transferrin and HFE compete for the TRF1 receptor, although transferrin has a higher affinity. Unbound HFE is raised to the surface of the cell which stimulates hepcidin expression

19

high iron levels and TRF2

high iron causes TRF2 to be expressed, binding more transferrin than TRf1

TRF2 upregulates more hepcidin expression downregulates transport of Fe out of the enterocytes

20

Too much iron causes more ____ to be produced than _____. Transferrins then bind more ______ than _____ because more is expressed. TRF2 binding stimulates ____ expression

TRF2 than TRF1

transferrins bind more TRF2 than TRF1

stimulates hepcidin production

hepcidin downregulates ferroportin which decreases Fe secretion out of enterocytes