Iron Cycle Flashcards

1
Q

Which form of iron is best absorbed in the intestine?

A

Heme iron & Ferrous iron (Fe²⁺)

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2
Q

What is the main site of iron absorption in the gastrointestinal tract?

A

Duodenum

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3
Q

Which protein transports iron from enterocytes into the bloodstream?

A

Ferroportin.

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4
Q

What is the role of DMT1 (Divalent Metal Transporter 1)?

A

Transports iron across the intestinal epithelium.

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5
Q

What enhances non-heme iron absorption?

A

Vitamin C

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6
Q

What enzyme reduces **Fe³⁺ (Ferric) to Fe²⁺ (Ferrous) in enterocytes for absorption?

A

Ferrireductase (Dcytb).

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7
Q

Which protein stores iron inside enterocytes?

A

Ferritin.

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8
Q

What happens to iron after being exported from enterocytes?

A

Hephaestin oxidizes Fe²⁺ to Fe³⁺ for transport by transferrin

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9
Q

Which protein binds iron in plasma and delivers it to cells?


A

Transferrin

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10
Q

What condition reduces intestinal iron absorption?


A

Vitamin C deficiency.

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11
Q

What is the primary function of iron in the body?

A

Oxygen transport.

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12
Q

Iron is an essential component of:

A

Hemoglobin, Myoglobin, and Cytochromes.

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13
Q

Where is the majority of iron stored in the body?

A

Hemoglobin

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14
Q

How does iron contribute to immune function?

A

Enhances macrophage activity, T-cell proliferation, and bacterial growth restriction.

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15
Q

Cytochrome enzymes containing iron are critical for:

A

Electron transport chain (ATP production).

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16
Q

What is the main regulatory hormone for iron homeostasis?


17
Q

What happens to hepcidin levels when iron levels are high?

A

Hepcidin increases to block iron absorption.

18
Q

How does hepcidin regulate iron?


A

Blocks ferroportin to prevent iron release into circulation.

19
Q

What condition decreases hepcidin levels?


20
Q

Transferrin saturation is a marker of:


A

Iron stores, iron deficiency, and iron overload

21
Q

Ferritin primarily functions as:


A

An iron storage protein.

22
Q

Hepcidin decreases plasma iron levels by acting on which protein?


A

Ferroportin

23
Q

Which factor increases hepcidin production?


A

Iron overload.

24
Q

What decreases hepcidin production?


A

Erythropoietic stimulation.

25
The transferrin receptor is critical for iron uptake because:
It binds transferrin–iron complexes for receptor-mediated endocytosis.
26
Which condition is associated with iron overload?

Hemochromatosis
27
What gene mutation is linked to hereditary hemochromatosis?
HFE gene.
28
Which lab test best reflects iron stores?
Ferritin
29
Iron-deficiency anemia is characterized by:
Microcytic hypochromic red blood cells
30
Common causes of iron-deficiency anemia:
Chronic blood loss, pregnancy, poor diet
31
What is the primary treatment for iron-deficiency anemia?
Iron supplementation.
32
Which test differentiates iron-deficiency anemia from anemia of chronic disease?
Ferritin
33
What are the complications of iron overload?
Liver cirrhosis, diabetes, cardiomyopathy
34
What is the best treatment for hereditary hemochromatosis?
Phlebotomy
35
What is a major cause of secondary iron overload?
Repeated blood transfusions.
36
A 45-year-old man presents with fatigue, joint pain, and bronze skin pigmentation. Lab tests show high ferritin, high transferrin saturation, and low hepcidin. What is the most likely diagnosis?
A: Hereditary Hemochromatosis. Next Steps: * Confirm HFE gene mutation. * Start phlebotomy therapy.