Deck 11: Iron Metabolism

Question 1

Which two organs are the major storage sites for iron in a normal individual?

A) Lymph nodes and muscle
B) Bone marrow and pancreas
C) Spleen and heart
D) Liver and spleen

Answer 1

Liver and spleen

Question 2

Where is the largest percentage of iron in the body located?

A) Stored in the bone marrow
B) Stored in the liver
C) Attached to hemoglobin in erythrocytes
D) In the cytoplasm of macrophages

Answer 2

Attached to hemoglobin in erythrocytes

Question 3

What is the plasma carrier protein for iron?

A) Ferritin
B) Transferrin
C) Albumin
D) Hemosiderin

Answer 3

Transferrin

Question 4

A congenital deficiency of transferrin results in:

A) Severe anemia
B) Reduced absorption of iron
C) Increased excretion of iron
D) Decreased storage of iron in organs

Question 5

Why is it not advisable for people with adequate iron stores to take supplemental iron?

A) Iron overload is a risk.
B) The RBC count will increase.
C) Erythropoietin will increase.
D) Severe anemia is a risk.

Question 6

A bone marrow Prussian blue stain shows blue granules inside of macrophages. What disorder can be ruled out by this result?

A) Iron overload
B) Iron deficiency
C) Chronic disease
D) Lead poisoning

Question 7

The serum iron and TIBC results given in Question 10 are consistent with:

A) Iron overload
B) Iron toxicity
C) Iron deficiency
D) Acute infection

Question 8

Heme is composed of iron and:

A) Globin chains
B) Oxygen
C) Methemoglobin
D) Protoporphyrin IX

Question 9

Which of the following stains blue with the Prussian blue stain?

A) Ferritin
B) Hemosiderin
C) Transferrin
D) Both ferritin and hemosiderin

Question 10

Which of the following is true about iron absorption?

A) It occurs primarily in the stomach.
B) Phytates and tannates enhance its absorption.
C) Ascorbic acid inhibits its absorption.
D) It must be in ferrous form for absorption.

Question 11

The proportion of hemosiderin to ferritin increases when:

A) Iron stores increase.
B) Anemia is present.
C) Transferrin increases.
D) Erythropoietin increases.

Question 12

Which of the following is true for transferrin?

A) It can bind two molecules of ferrous iron.
B) It binds to a transferrin receptor found on the cell membrane.
C) It is synthesized in the kidney.
D) It is normally about 50% saturated with iron.

Question 13

Which of the following is true regarding iron absorption?

A) Vegetable nonheme iron is more easily absorbed than heme iron.
B) Most of the iron consumed is absorbed.
C) Ascorbic acid (vitamin C) enhances absorption.
D) Those who are iron deficient absorb less iron.

Question 14

A patient has a serum iron of 10 g/dL and a total iron-binding capacity (TIBC) of 490 g/dL. What is the percent saturation of transferrin?

A) 2%
B) 25%
C) 40%
D) 60%

Question 15

Good dietary sources of iron include all except:

A) Meat
B) Fruit
C) Fortified flour
D) Legumes

Question 16

What is the mechanism for iron toxicity if iron is present in excess amounts?

A) Acts as a catalyst in forming free oxygen radicals
B) Impedes hematopoiesis
C) Reduces hemoglobin to methemoglobin
D) Interferes with globin synthesis

Question 17

What are hemosiderin and ferritin?

A) Enzymes necessary for iron absorption
B) Carrier proteins for iron
C) Storage forms of iron
D) Iron regulatory chemicals

Question 18

Transferrin receptors can be measured and are elevated when:

A) Erythropoietin increases.
B) Transferrin increases.
C) Iron stores are decreased.
D) Chronic disease is present.

Question 19

The serum ferritin is used more often than bone marrow or liver biopsies to assess iron stores because it is:

A) A more direct measurement
B) More accurate
C) More precise
D) Less invasive