Question 1

Fetal hematopoiesis occurs primarily in which structure?
A)Gut
B)Spleen
C)Bone marrow
D)Thymus

Accepted Answer

The spleen is the largest of the secondary lymphoid organs and the primary site of fetal hematopoiesis. The bone marrow and thymus are other primary lymphoid organs. Peyer patches in the small intestine are considered secondary lymphoid organs.

Question 2

What is the life span of platelets (in days)?
A)10
B)30
C)90
D)120

Accepted Answer

A platelet circulates for approximately 8 to 11 days and ages. Macrophages of the mononuclear phagocyte system, mostly in the spleen, remove platelets.

Question 3

What does the student learn about erythrocytes?
A)Erythrocytes contain a nucleus, mitochondria, and ribosomes.
B)Erythrocytes synthesize proteins.
C)Erythrocytes have the ability to change shape to squeeze through microcirculation.
D)Erythrocytes are more abundant in women than men.

Accepted Answer

Reversible deformity enables the erythrocyte to assume a more compact torpedo-like shape, squeeze through the microcirculation, and return to normal. The mature erythrocyte lacks a nucleus and cytoplasmic organelles so it cannot synthesize protein or carry out oxidative reactions. Men have more erythrocytes than women (48% to 42% respectively).

Question 4

Without prior exposure to an antigen, which cells are able to destroy some types of tumor cells and some virus-infected cells?
A)Lymphocytes
B)Plasma cells
C)Megakaryocytes
D)Natural killer (NK) cells

Accepted Answer

NK cells, which resemble large granular lymphocytes, kill some types of tumor cells (in vitro) and some virus-infected cells without being induced by previous exposure to these antigens. This capability is not true of lymphocytes, plasma cells, or megakaryocytes.

Question 5

What are blood cells that differentiate into macrophages known as?
A)Monocytes
B)Neutrophils
C)Eosinophils
D)Basophils

Accepted Answer

Monocytes migrate into a variety of tissues and fully mature into tissue macrophages and myeloid dendritic cells. Neutrophils, eosinophils, and basophils do not undergo this transformation.

Question 6

What is the life span of an erythrocyte (in days)?
A)20 to 30
B)60 to 90
C)100 to 120
D)200 to 240

Accepted Answer

Because it cannot undergo mitotic division, the erythrocyte has a limited life span of up to approximately 120 days.

Question 7

By which structure are mature erythrocytes removed from the bloodstream?
A)Liver
B)Lymph nodes
C)Thymus
D)Spleen

Accepted Answer

At the end of their life spans, old erythrocytes are removed by tissue macrophages, primarily in the spleen.

Question 8

A professor explains to a class that the reason lymph nodes enlarge and become tender during infection is because of what reason?
A)B lymphocytes proliferate.
B)The nodes are inflamed.
C)The nodes fill with purulent exudate.
D)The nodes are not properly functioning.

Accepted Answer

The B lymphocyte proliferation in response to significant antigen (e.g., during infection) may result in lymph node enlargement and tenderness (reactive lymph node). The nodes are not specifically inflamed or filled with purulent exudate.

Question 9

What is plasmin's role in the clotting process?
A)Stimulates platelet aggregation.
B)Inhibits platelet adhesion and aggregation.
C)Prevents the conversion of prothrombin to degrade the fibrin within blood clots.
D)Degrades the fibrin within blood clots.

Accepted Answer

Plasmin (also called fibrinase or fibrinolysin) is a serine protease that degrades fibrin polymers in clots. It is not capable of stimulating platelet aggregation, inhibiting platelet adhesion, or preventing conversion of prothrombin.

Question 10

What is the most abundant class of plasma protein?
A)Globulin
B)Albumin
C)Clotting factors
D)Complement proteins

Accepted Answer

Albumin (approximately 60% of total plasma protein at a concentration of about 4 g/dL) is the most abundant plasma protein.

Question 11

Which of these is the role of nitric oxide (NO) in hemostasis?
A)Stimulates the release of fibrinogen to maintain the platelet plug.
B)Stimulates the release of clotting factors V and VII.
C)Causes vasoconstriction and stimulates platelet aggregation.
D)Controls platelet activation through in concert with prostacyclin.

Accepted Answer

Endothelial cell NO synthase produces NO, which controls platelet activation in concert with prostacyclin. The other options do not present an accurate description of the role of NO in hemostasis.

Question 12

The drug heparin acts in hemostasis by which processes?
A)Inhibiting thrombin and antithrombin III (AT-III)
B)Preventing the conversion of prothrombin to thrombin
C)Shortening the fibrin strands to retract the blood clot
D)Degrading the fibrin within blood clots

Accepted Answer

Clinically administered heparin binds to AT-III and induces a conformational change that greatly enhances its activity. Under normal conditions, the presence of endothelial cell heparin sulfate and available AT-III in the circulation cooperate to protect the vessels from the effects of spontaneously activated thrombin. Heparin does not prevent the conversion of prothrombin to thrombin, shorten fibrin strands, or degrade the fibrin in blood clots.

Question 13

A patient has pernicious anemia and asks the healthcare professional to explain the disease. Which statement by the professional is most accurate?
A)The lack of certain foods in your diet
B)Your body cannot absorb vitamin B₁₂.
C)You are not getting enough vitamin C.
D)Your bone marrow has stopped working.

Accepted Answer

Dietary vitamin B₁₂ is a large molecule that requires a protein secreted by parietal cells in the stomach (intrinsic factor [IF]) to transport across the ileum. Defects in IF production lead to decreased B₁₂ absorption and pernicious anemia. A lack of certain foods (i.e., meat) might lead to iron-deficiency anemia. Vitamin C lack would not lead to anemia, but in a severe state could lead to scurvy. If the bone marrow had totally failed, that would be termed aplastic anemia.

Question 14

What are granulocytes that contain granules of vasoactive amines, such as histamine, called?
A)Neutrophils
B)Eosinophils
C)Monocytes
D)Basophils

Accepted Answer

Basophils contain cytoplasmic granules that hold an abundant mixture of biochemical mediators, including histamine, chemotactic factors, proteolytic enzymes, and an anticoagulant (heparin). These substances are not found in neutrophils, monocytes, or eosinophils.

Question 15

What is the effect of low plasma albumin?
A)Clotting factors decrease, thus increasing the chance of prolonged bleeding.
B)Fewer immunoglobulins are synthesized, thus impairing the immune function.
C)Less iron is stored, thus increasing the incidence of iron deficiency anemia.
D)Osmotic pressure decreases; thus water moves from the capillaries to the interstitium.

Accepted Answer

In the case of decreased production (e.g., cirrhosis, other diffuse liver diseases, protein malnutrition) or excessive loss of albumin (e.g., certain kidney diseases, extensive burns), the reduced oncotic pressure leads to excessive movement of fluid and solutes into the tissues and decreased blood volume. Low plasma albumin does not affect clotting factors, immunoglobulins, or iron.

Question 16

What is the role of thromboxane A (TXA₂) in the secretion stage of hemostasis?
A)Stimulates the synthesis of serotonin.
B)Promotes vasodilation.
C)Stimulates platelet aggregation.
D)Promotes formation of cyclooxygenase.

Accepted Answer

Platelet aggregation is primarily stimulated by TXA₂ and adenosine diphosphate (ADP), which induce functional fibrinogen receptors on the platelet. Thromboxane A is not involved with serotonin synthesis, vasodilation, or production of cyclooxygenase.

Question 17

A patient has chronic anemia associated with chronic renal failure. What substance does the healthcare professional tell the patient is needed to treat this anemia?
A)Iron
B)Erythropoietin
C)Cobalamin (vitamin B12)
D)Folate

Accepted Answer

One of the most significant advances in the study of hematopoietic growth factors has been the development of erythropoietin for individuals with chronic renal failure. The other options are not associated with the treatment of chronic anemia.

Question 18

Which hemoglobin is made from oxidized ferric iron (Fe³⁺) and lacks the ability to bind oxygen?
A)Deoxyhemoglobin
B)Oxyhemoglobin
C)Methemoglobin
D)Glycosylated hemoglobin

Accepted Answer

Without reactivation by methemoglobin reductase, the Fe³⁺-containing hemoglobin (methemoglobin) cannot bind oxygen. Deoxyhemoglobin is hemoglobin available for oxygen binding. Oxyhemoglobin is bound with oxygen. Glycosylated hemoglobin is hemoglobin with which glucose is bound.

Question 19

Which of these are formed elements of the blood that are not cells but are disk-shaped cytoplasmic fragments essential for blood clotting?
A)Monocytes
B)Platelets
C)Macrophages
D)Erythrocytes

Accepted Answer

Platelets (thrombocytes) are not true cells but are disk-shaped cytoplasmic fragments that are essential for blood coagulation and control of bleeding. Monocytes, macrophages, and erythrocytes are cells.

Question 20

What is the consequence of a splenectomy?
A)The level of iron in circulation increases.
B)Antibody production increases to improve immune function.
C)The number of defective cells in circulation increases.
D)The number of clotting factors increases.

Accepted Answer

Splenic absence from any cause (e.g., atrophy, traumatic injury, removal because of disease) has several secondary effects on the body, among them an increase in morphologically defective blood cells in the circulation, confirming the spleen's role in removing old or damaged cells. Loss of the spleen does not increase iron blood levels, increase antibody production, or increase the number of clotting factors.

Quiz 28: Structure and Function of the Hematologic System

Fetal hematopoiesis occurs primarily in which structure?

What is the life span of platelets (in days) ?

What does the student learn about erythrocytes?

Without prior exposure to an antigen, which cells are able to destroy some types of tumor cells and some virus-infected cells?

What are blood cells that differentiate into macrophages known as?

What is the life span of an erythrocyte (in days) ?

By which structure are mature erythrocytes removed from the bloodstream?

A professor explains to a class that the reason lymph nodes enlarge and become tender during infection is because of what reason?

What is plasmin's role in the clotting process?

What is the most abundant class of plasma protein?

Which of these is the role of nitric oxide (NO) in hemostasis?

The drug heparin acts in hemostasis by which processes?

A patient has pernicious anemia and asks the healthcare professional to explain the disease. Which statement by the professional is most accurate?

What are granulocytes that contain granules of vasoactive amines, such as histamine, called?

What is the effect of low plasma albumin?

What is the role of thromboxane A (TXA₂) in the secretion stage of hemostasis?

A patient has chronic anemia associated with chronic renal failure. What substance does the healthcare professional tell the patient is needed to treat this anemia?

Which hemoglobin is made from oxidized ferric iron (Fe³⁺) and lacks the ability to bind oxygen?

Which of these are formed elements of the blood that are not cells but are disk-shaped cytoplasmic fragments essential for blood clotting?

What is the consequence of a splenectomy?