CH5 - Red Blood Cell Disorders Flashcards Preview

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Flashcards in CH5 - Red Blood Cell Disorders Deck (284)
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1

What is Anemia?

Reduction in circulating red blood cell (RBC) mass

2

What does anemia present with?

signs and symptoms of hypoxia; 1. Weakness, fatigue, and dyspnea 2. Pale conjunctiva and skin 3. Headache and lightheadedness 4. Angina, especially with preexisting coronary artery disease

3

How is RBC mass measured?

Hemoglobin (Hb), hematocrit (Hct), and RBC count are used as surrogates for RBC mass, which is difficult to measure

4

Anemia is defined as what (in terms of Hb)?

Hb<12.5 g/dL in females (normal Hb is 13.5-17.5 g/dL in males and 12.5-16.0 g/dl. in females)

5

What is the basis for anemia classification?

Based on mean corpuscular volume (MCV), anemia can be classified as microcytic (MCV 100)

6

What does the MCV give you an indication of in anemia?

size of the red blood cell

7

Microcytic anemias are due to

decreased production of hemoglobin.

8

RBC progenitor cells in the bone marrow are?

large and normally divide multiple times to produce smaller mature cells (MCV = 80-100)

9

Microcytosis is due to?

an "extra" division which occurs to maintain hemoglobin concentration.

10

Hemoglobin is made of

heme and globin:

11

heme is composed of?

iron and protoporphyrin

12

A decrease in what components leads to microcytic anemia?

iron, protoporphyrin and globin

13

Microcytic anemias include

(1) iron deficiency anemia, (2) anemia of chronic disease, (3) sideroblastic anemia, and (4) thalassemia.

14

Iron deficiency anemia is due to?

decreased levels of iron -> dec heme -> dec hemoglobin —» microcytic anemia

15

What is the most common type of anemia?

iron deficiency anemia

16

What is the most common nutritional deficiency in the world?

Lack of iron, affecting roughly 1/3 of world's population

17

Iron is consumed in what forms?

heme (meat-derived) and non-heme (vegetable-derived) forms

18

Absorption of iron occurs in the?

duodenum, Enterocytes have heme and non-heme (DMT1) transporters; the heme form is more readily absorbed

19

How do enterocytes transport iron?

across the cell membrane into blood via ferroportin

20

How does transferrin transports iron?

in the blood and delivers it to liver and bone marrow macrophages for storage.

21

Stored intracellular iron is bound to what?

ferritin, which prevents iron from forming free radicals via the Fenton reaction

22

Laboratory measurements of iron status

1) serum iron 2)TIBC 3) % saturation 4) Serum ferritin

23

What does the serum iron measure?

Serum iron is a measure of iron in the blood

24

What does total iron-binding capacity (TIBC) measure?

transferrin molecules in the blood

25

What does % saturation of iron measure?

percentage of transferrin molecules that are bound by iron (normal is 33%)

26

What does serum ferritin measure?

reflects iron stores in macrophages and the liver

27

What is iron deficiency is usually caused by?

dietary lack or blood loss

28

What is iron deficiency is usually caused by in infants?

breast-feeding (human milk is low in iron)

29

What is iron deficiency is usually caused by in children?

poor diet

30

What is iron deficiency is usually caused by in adults?

(20-50 years old)—peptic ulcer disease in males and menorrhagia or pregnancy in females