U4 LEC: IRON KINETICS AND METABOLISM

Question 1

Iron kinetics happen in the?

Answer 1

intestinal lumen

Question 2

T/F: Iron is not endogenouslly produced.

Answer 2

True

Question 3

Forms of Iron from our diet

Answer 3

• heme form
• ionic form (ferric form)

Question 4

If Iron is in heme form, to where does it get transported and by what?

Answer 4

Enterocyte, Heme transporter

Question 5

This degrades the heme for release of Iron from Protoporphyrin IX.

Answer 5

Heme Oxygenase

Question 6

This reduces the ferric Iron to ferrous Iron.

Answer 6

Duodenal Cytochrome B

Question 7

Ferrous iron can be absorbed in enterocyte through the?

Answer 7

Divalent Metal Transporter 1 (DMT1)

Question 8

Excess iron can be stored as?

Answer 8

Ferritin

Question 9

Stored Iron

Answer 9

Ferritin

Question 10

Iron released from the enterocyte then in to the circulation is through the?

Answer 10

Ferroportin

Question 11

Aside from enterocytes, these cells also have Ferroportin.

Answer 11

• hepatocytes
• macrophages

Question 12

Protein produced by the liver responsible for transporting ferric Iron

Answer 12

Transferrin

Question 13

T/F: Before Transferrin transports the Iron, it must be in Ferrous form

Answer 13

False

must be reoxidized back to ferric state

Question 14

This is responsible for the reoxidation of ferrous to ferric state so it can bind to Transferrin.

Answer 14

Hephaestin

Question 15

Transferrin will carry Iron to ________ for heme synthesis to occur on developing eryhthroblasts.

Answer 15

Bone Marrow

Question 16

Excessive iron leads to?

Answer 16

iron toxicity and damage to the heart, liver, internal organs

Question 17

This is responsible to maintain iron homeostasis, produced in the liver that blocks Ferroportin.

Answer 17

Hepcidin

Question 18

Hepcidin blocks Ferroportin to?

Answer 18

prevent absorption and release of Iron in the circulation

Question 19

Increased Serum Fe, _______ Hepcidin

Answer 19

Increased

Question 20

Iron is also excreted through?

Answer 20

enterocyte (sloughed off)

Question 21

Absorption of excessive iron, can lead to iron toxicity

Answer 21

Primary Hemochromatosis

Question 22

Overdose of Iron due to medical treatments, drugs, supplements

Answer 22

Secondary Hemochromatosis

Question 23

Protein of hepatic origin that inhibits Ferroportin from transporting iron out of the enterocyte

Answer 23

Hepcidin

Question 24

T/F: All cells except the mature RBC can store Ferritin.

Answer 24

True

Mature RBC is the end receiver of iron used to synthesize Hgb

Question 25

1 Ferritin is equal to?

Answer 25

4000 Iron Ion Reserve

Question 26

Partially degraded Ferritin, less metabolically active and available

Answer 26

Hemosiderin

Question 27

These are found in RTE cells.

Answer 27

Hemosiderin granules

Question 28

These are cells that line the convoluted tubules.

Answer 28

Renal Tubular Epithelial Cells (RTE Cells)

Question 29

If patient has Intravascular Hemolysis (rupture of RBC in circulation), it will rseult to?

Answer 29

Hemoglobinuria

Question 30

In Hemoglobinuria, RTE tries to reabsorb the excessive Hgb and will deposit to RTE as?

Answer 30

iron as Hemosiderin granules

Question 31

Iron is stained by?

Answer 31

Prussian Blue

Question 32

Screening Tests for defects in Iron/Hgb Metabolism added to CBC

Answer 32

• Serum Fe
• TIBC
• % Transferrin Saturation
• Serum Ferritin

Question 33

If results are not yet definite for diagnosis or not matching , it is termed as?

Answer 33

equivocal

Question 34

If results are equivocal, these additional tests can be done:

Answer 34

• Prussian blue staining
• Hgb content of Reticulocytes
• Soluble Transferrin Receptor
• sTfR/log ferritin
• ZPP

Question 35

This is the Iron present in the circulation, or an indicator of available transport Iron.

Answer 35

Serum Iron Level (Serum Fe2+)

Question 36

Decreased (↓) Iron due to lack of dietary intake, increased need of Iron in pregnant women or developing children, chronic bleeding

Answer 36

Iron Deficiency Anemia (depletion of Ferritin)

Question 37

This refers to profused bleeding due to traumatic condition (surgery, gunshot, stab)

Answer 37

Acute Bleeding (↓ Decreased blood volume, abrupt losing)

Question 38

This refers to slowly losing small amounts of blood due to GI bleeding, heavy menstruation

Answer 38

Chronic bleeding (Normal blood volume but losing Iron)

Question 39

IDA

What is depleted first?

Answer 39

Ferritin

Question 40

Genetic condition in which patient has increased absorption of iron (abnormal iron overload)

Answer 40

Primary Hemochromatosis

Question 41

This is an acquired condition due to taking of iron supplements, medicine.

Answer 41

Secondary Hemochromatosis

Question 42

This conditions stems from malignant conditions such as cancer, TB, systemic lupus erythematosus, rheumatoid arthritis.

Answer 42

Anemia of Chronic Inflammation (Affected ferrokinetics)

Question 43

ACI

In presence of inflammation, liver will produce?

Answer 43

more Hepcidin (depleted serum iron)

Question 44

Hepcidin and C-reactive proteins are called?

Answer 44

Acute Phase Reactants (Elevated in inflammation)

Question 45

Requirements for Serum Iron Level testing

Answer 45

• fasting (intake will cause false elevated iron)
• early morning specimen (high in the morning, low in afternoon)

Question 46

Serum Iron Level

Reference Value

Answer 46

50-160 ug/dL

Question 47

Serum Iron Level

Conditions

Answer 47

IDA: Decreased (↓)
HEMO: Increased (↑)
ACI: Decreased (↓)