Chapter 28: Structure and Function of the Hematologic System Flashcards
What is the most abundant class of plasma protein?
a. Globulin
c. Clotting factors
b. Albumin
d. Complement proteins
ANS: B
Albumin (approximately 60% of total plasma protein at a concentration of about 4 g/dl) is
the most abundant plasma protein.
PTS: 1 REF: Page 946
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.
ANS: D
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. The other options are not accurate descriptions of the
effect of low plasma albumin.
PTS: 1 REF: Page 946
What is the life span of an erythrocyte (in days)?
a. 20 to 30
c. 100 to 120
b. 60 to 90
d. 200 to 240
ANS: C
Because it cannot undergo mitotic division, the erythrocyte has a limited life span of
approximately 120 days.
PTS: 1 REF: Pages 947-948
Which statement concerning erythrocytes is true?
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. Erythrocyte colony-stimulating factor (E-CSF) stimulates erythrocytes.
ANS: C
Reversible deformity enables the erythrocyte to assume a more compact torpedo-like
shape, squeeze through the microcirculation, and return to normal. The other options are
not accurate statements about erythrocytes.
Granulocytes that contain granules of vasoactive amines, such as histamine, are called:
a. Neutrophils
c. Monocytes
b. Eosinophils
d. Basophils
ANS: D
Basophils contain cytoplasmic granules that hold an abundant mixture of biochemical
mediators, including histamine, chemotactic factors, proteolytic enzymes, and an
anticoagulant (heparin) (see Figure 27-3, C). This is not an accurate description of any of
the other options.
PTS: 1 REF: Page 949
Which of the following are formed elements of the blood that are not cells but are
disk-shaped cytoplasmic fragments essential for blood clotting?
a. Monocytes
c. Macrophages
b. Platelets
d. Erythrocytes
ANS: B
Platelets (thrombocytes) are not true cells but are disk-shaped cytoplasmic fragments that
are essential for blood coagulation and control of bleeding. This description is not accurate
for any of the other options.
PTS: 1 REF: Pages 950-951
Blood cells that differentiate into macrophages are known as:
a. Monocytes
c. Eosinophils
b. Neutrophils
d. Basophils
ANS: A
Only monocytes migrate into a variety of tissues and fully mature into tissue
macrophages and myeloid dendritic cells (see Table 27-3).
PTS: 1 REF: Page 950
Without prior exposure to an antigen, which cells are able to destroy some types of tumor cells and some virus-infected cells? a. Lymphocytes c. Megakaryocytes b. Plasma cells d. Natural killer (NK) cells
ANS: D
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 the other options.
PTS: 1 REF: Page 950
What is the life span of platelets (in days)?
a. 10
c. 90
b. 30
d. 120
ANS: A
A platelet circulates for approximately 10 days and ages. Macrophages of the mononuclear
phagocyte system, mostly in the spleen, remove platelets.
PTS: 1 REF: Page 951
Fetal hematopoiesis occurs in which structure?
a. Gut
c. Bone marrow
b. Spleen
d. Thymus
ANS: B
The spleen is the largest of the secondary lymphoid organs and the site of fetal
hematopoiesis.
PTS: 1 REF: Page 951
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.
ANS: C
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. This description of the consequence of a splenectomy is
not accurate for the other options.
PTS: 1 REF: Pages 951-952
During an infection, why do lymph nodes enlarge and become tender?
a. B lymphocytes proliferate.
b. The nodes are inflamed.
c. The nodes fill with purulent exudate.
d. The nodes are not properly functioning.
ANS: A
The B lymphocyte proliferation in response to significant antigen (e.g., during infection)
may result in lymph node enlargement and tenderness (reactive lymph node). This
description is not accurate for the other options.
PTS: 1 REF: Page 954
Which blood cells are the chief phagocytes involved in the early inflammation process?
a. Neutrophils
c. Eosinophils
b. Monocytes
d. Erythrocytes
ANS: A
Neutrophils are the chief phagocytes of early inflammation.
PTS: 1 REF: Page 949
Which blood cells are biconcave in shape and have the capacity to be reversibly deformed? a. Neutrophils c. Eosinophils b. Monocytes d. Erythrocytes
ANS: D
The erythrocyte’s size and shape are ideally suited to its function as a gas carrier. A red
blood cell (RBC) is a small disk with two unique properties: (1) a biconcave shape and (2)
the capacity to be reversibly deformed. These are characteristics not observed in any of the
other options.
PTS: 1 REF: Page 948
Which hemoglobin is made from oxidized ferric iron (Fe3+) and lacks the ability to bind oxygen? a. Deoxyhemoglobin c. Methemoglobin b. Oxyhemoglobin d. Glycosylated hemoglobin
ANS: C
Without reactivation by methemoglobin reductase, the Fe3+-containing hemoglobin
(methemoglobin) cannot bind oxygen. This capability is not true of the other types of
hemoglobin mentioned.
PTS: 1 REF: Page 961
The absence of parietal cells would prevent the absorption of an essential nutrient
necessary to prevent which type of anemia?
a. Iron deficiency
c. Folic acid deficiency anemia
b. Pernicious anemia
d. Aplastic anemia
ANS: B
Dietary vitamin B12 is a large molecule that requires a protein secreted by parietal cells
into the stomach (intrinsic factor [IF]) to transport across the ileum. Defects in IF
production lead to decreased B12 absorption and pernicious anemia. The other options are
not the result of this process.
PTS: 1 REF: Page 962
Which nutrients are necessary for the synthesis of DNA and the maturation of erythrocytes? a. Protein and niacin c. Cobalamin (vitamin B12) and folate b. Iron and vitamin B6 (pyridoxine) d. Pantothenic acid and vitamin C
ANS: C
Cobalamin and folate are necessary for the synthesis of DNA and for the maturation of
erythrocytes. The remaining options are not necessary for these processes to occur.
PTS: 1 REF: Page 962 | Table 27-6
Which nutrients are necessary for hemoglobin synthesis?
a. Protein and niacin
c. Cobalamin (vitamin B12) and folate
b. Iron and vitamin B6 (pyridoxine)
d. Pantothenic acid and vitamin C
ANS: B
Iron and B6 (pyridoxine) are necessary for hemoglobin synthesis (see Table 27-6). The
remaining options are not necessary for hemoglobin synthesis.
PTS: 1 REF: Page 962 | Table 27-6
Recycling of iron from erythrocytes is made possible by which of the following?
a. Transferrin
c. Apoferritin
b. Hemosiderin
d. Erythropoietin
ANS: A
Transferrin is recycled (transferrin cycle) in the following manner: (1) the transferrin-iron
complex binds to a transferring receptor on the erythroblast’s plasma membrane; (2) the
complex moves into the cell by receptor-mediated endocytosis; (3) iron is released
(dissociated) from transferrin; and (4) the dissociated transferrin is returned to the
bloodstream for reuse. The other options do not present an accurate description of the
recycling of erythrocytic iron.
PTS: 1 REF: Pages 963-964
By which structure are mature erythrocytes removed from the bloodstream?
a. Liver
c. Thymus
b. Lymph nodes
d. Spleen
ANS: D
After approximately 100 to 120 days in the circulation, old erythrocytes are removed by
tissue macrophages, primarily in the spleen.
PTS: 1 REF: Page 962
Which substance is used to correct the chronic anemia associated with chronic renal failure? a. Iron c. Cobalamin (vitamin B12) b. Erythropoietin d. Folate
ANS: B
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.
PTS: 1 REF: Pages 960-961
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.
ANS: C
Platelet aggregation is primarily stimulated by TXA2 and adenosine diphosphate (ADP),
which induce functional fibrinogen receptors on the platelet. Th
Which of the following 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 cyclic adenosine monophosphate
(cAMP)–mediated signaling.
ANS: D
Endothelial cell NO synthase produces NO, which controls platelet activation through
cAMP-mediated signaling. The other options do not present an accurate description of the
role of NO in hemostasis.
PTS: 1 REF: Page 966 | Figure 27-18
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
ANS: A
Clinically administered heparin or heparin sulfate (on the surface of endothelial cells)
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. The other options do not accurately describe the role heparin plays in
hemostasis.
PTS: 1 REF: Page 970
