Macrophages and Hemoglobin Destruction Process

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What is the normal hematocrit percentage in men?

45 percent (correct)

47 percent

40 percent

42 percent

How is the hematocrit measured?

By analyzing the color of erythrocytes

By counting the number of leukocytes

By centrifuging a blood sample (correct)

By measuring the amount of iron in the blood

What is the volume of plasma in an average-sized person with a 45 percent hematocrit?

3.0 L (correct)

4.0 L

3.5 L

2.5 L

What is the quantity of hemoglobin that red blood cells can concentrate in their cell fluid?

34 grams in each 100 milliliters of cells Signup and view all the answers

Why is it important to understand the means by which iron is utilized in the body?

To ensure the formation of myoglobin and cytochromes Signup and view all the answers

What is the approximate volume of blood in an average-sized person (70 kg)?

5.5 L Signup and view all the answers

What is the primary function of hemoglobin in the body?

To combine with oxygen in the peripheral tissue capillaries Signup and view all the answers

What determines the binding affinity of the hemoglobin for oxygen?

The types of hemoglobin chains in the hemoglobin molecule Signup and view all the answers

What happens when reticulocytes leave the bone marrow and pass into the blood stream?

They continue to form minute quantities of hemoglobin for another day or so Signup and view all the answers

What alteration in the hemoglobin molecule leads to sickle cell anemia?

Substitution of glutamic acid for valine at one point in each of the two beta chains Signup and view all the answers

Where is excess iron deposited in the body?

In the liver hepatocytes and reticuloendothelial cells Signup and view all the answers

What is the role of transferrin in iron metabolism?

It transports iron to the mitochondria for heme synthesis Signup and view all the answers

What happens to old abnormal red cells when the spleen is removed?

Their number increases considerably in the blood circulation Signup and view all the answers

What happens when red blood cells burst and release their hemoglobin?

The hemoglobin is phagocytized immediately by macrophages Signup and view all the answers

What is unique about transferrin's interaction with erythroblasts?

It binds with receptors in erythroblasts and forms ferritin directly Signup and view all the answers

What is stored as hemosiderin?

Iron combined with clusters of iron radicals and apoferritin Signup and view all the answers

What causes severe hypochromic anemia?

Failure to transport iron to erythroblasts by transferrin Signup and view all the answers

Where does most destruction of red blood cells occur?

In the liver hepatocytes and macrophages of the spleen and bone marrow Signup and view all the answers

Which of the following is the primary role of transferrin in the process described?

Transporting iron to the bone marrow for the production of new red blood cells Signup and view all the answers

In cases of chronic blood loss, why are RBCs smaller than normal and contain too little hemoglobin?

Inability to absorb enough iron from the intestines Signup and view all the answers

What condition may lead to megaloblastic anemia due to slow reproduction of erythroblasts in the bone marrow?

Inability to absorb vitamin B12 from the gastrointestinal tract Signup and view all the answers

What is the basic abnormality in pernicious anemia?

Atrophy of the stomach mucosa Signup and view all the answers

What is the role of intrinsic factor in the absorption of vitamin B12 from the gastrointestinal tract?

Combines with vitamin B12 in food for absorption by the gut Signup and view all the answers

What is the minimum amount of vitamin B12 required each day to maintain normal red cell maturation?

1-3 micrograms Signup and view all the answers

What is a common cause of maturation failure anemia?

Deficiency of folic acid and vitamin B12 absorption Signup and view all the answers

What leads to hemolytic anemia?

Hereditary abnormalities making RBCs fragile Signup and view all the answers

What characterizes RBCs in hereditary spherocytosis?

Small size and biconcave disc shape Signup and view all the answers

What causes the cells in sickle cell disease to become highly fragile?

Damage to the cell membrane by the precipitated hemoglobin Signup and view all the answers

What event in erythroblastosis fetalis leads to rapid rupture of Rh-positive RBCs in the fetus?

Attack by antibodies from an Rh-negative mother Signup and view all the answers

What causes the bloodforming organs to produce large quantities of extra RBCs in secondary polycythemia?

Hypoxia in the tissues Signup and view all the answers

What is the characteristic of physiological polycythemia in individuals living at high altitudes?

Ability to perform high levels of continuous work at rarefied atmosphere Signup and view all the answers

What distinguishes polycythemia vera from physiological polycythemia?

Genetic aberration in the blood cells Signup and view all the answers

What is the cause of excess production of RBCs in polycythemia vera?

Blast cells no longer stop producing RBCs when too many cells are already present Signup and view all the answers

What is the hematocrit percentage in polycythemia vera compared to the normal range?

60% to 70% Signup and view all the answers

What effect does polycythemia vera have on the total blood volume?

Increases almost twice normal Signup and view all the answers

What is a consequence of the entire vascular system becoming intensely engorged in polycythemia vera?

Many blood capillaries become plugged Signup and view all the answers

What condition causes a large number of early blast forms of RBCs to be released from the bone marrow into the blood?

Secondary polycythemia Signup and view all the answers

What type of secondary polycythemia occurs in those living at altitudes of 14,000 to 17,000 feet?

Physiological polycythemia Signup and view all the answers

What causes sickling, ruptured RBCs, and further decrease in oxygen tension in sickle cell disease crisis?

Low oxygen tension in the tissues Signup and view all the answers