Question 1

Where is iron absorbed?
A) Stomach
B) Duodenum
C) Proximal jejunum
D) Ascending colon

Accepted Answer

Iron is primarily absorbed in the duodenum, which is the first part of the small intestine. The acid in the stomach helps to convert dietary iron into a more absorbable form, and then the iron is transported into the duodenum for further absorption. The proximal jejunum also contributes to iron absorption, but to a lesser extent than the duodenum. The ascending colon is part of the large intestine and is not involved in iron absorption.

Question 2

Hemoglobin made from oxidized ferric iron (Fe¹¹¹)is called _____ and is unstable and lacks the ability to bind oxygen. A) deoxyhemoglobin B) oxyhemoglobin C) methemoglobin D) glycosylated hemoglobin

Accepted Answer

Hemoglobin made from oxidized ferric iron is called methemoglobin, which is unstable and lacks the ability to bind oxygen. Deoxyhemoglobin is hemoglobin with reduced or deoxygenated iron, oxyhemoglobin is hemoglobin with oxygenated iron, and glycosylated hemoglobin is hemoglobin with a glucose molecule attached to the protein.

Question 3

During an infection,lymph nodes enlarge and become tender because:
A) of the proliferation of macrophages.
B) the nodes are inflamed.
C) the nodes filled with purulent exudate.
D) the nodes are not functioning properly.

Accepted Answer

Lymph nodes enlarge and become tender during an infection primarily due to the proliferation of immune cells, such as macrophages and lymphocytes, as they respond to the infection.

Question 4

What is the role of plasmin in the clotting process?
A) It stimulates platelet aggregation.
B) It inhibits platelet adhesion and aggregation.
C) It prevents the conversion of prothrombin to degrade the fibrin within blood clots.
D) It degrades the fibrin within blood clots.

Accepted Answer

Plasmin is a protease that breaks down fibrin, the protein involved in blood clot formation. It is necessary for the dissolution of blood clots, a process known as fibrinolysis.

Question 5

How does the drug heparin act in hemostasis?
A) Heparin inhibits thrombin and factor XA.
B) Heparin prevents the conversion of prothrombin to thrombin.
C) Heparin shortens the fibrin strands to retract the blood clot.
D) Heparin degrades the fibrin within blood clots.

Accepted Answer

Heparin acts by inhibiting thrombin and factor XA, which are key players in the coagulation cascade. This prevents the formation of blood clots and therefore helps in preventing the formation of thrombi. Heparin does not prevent the conversion of prothrombin to thrombin or shorten fibrin strands, nor does it degrade fibrin within blood clots.

Question 6

Which nutrients are necessary for the hemoglobin synthesis? A) Protein and niacin B) Iron and vitamin B₆ (pyridoxine) C) Cobalamin (vitamin B₁₂)and folate D) Pantothenic acid and vitamin C

Accepted Answer

Iron and vitamin B6 are directly involved in the synthesis of hemoglobin, with iron being a core component of the hemoglobin molecule and vitamin B6 playing a role in the synthesis of heme.

Question 7

Which of the following shows a correct sequence in the development of erythrocytes?
A) Normoblast,reticulocyte,and basophilic erythroblast
B) Basophilic erythroblast,normoblast,and reticulocyte
C) Normoblast,committed proerythroblast,and reticulocyte
D) Committed proerythroblast,normoblast,and reticulocyte

Accepted Answer

Normoblast, committed proerythroblast and then reticulocyte is the correct sequence in the development of erythrocytes.

Question 8

Removing the stomach with its parietal cells would prevent the absorption of an essential nutrient necessary to prevent which type of anemia?
A) Iron deficiency
B) Pernicious anemia
C) Folic acid deficiency anemia
D) Aplastic anemia

Accepted Answer

Parietal cells in the stomach secrete intrinsic factor that aids in the absorption of vitamin B12. Pernicious anemia is a type of anemia that results from a deficiency of vitamin B12, which can occur when there is a lack of intrinsic factor or when the body is unable to absorb vitamin B12 due to autoimmune destruction of the parietal cells. Therefore, removing the stomach with its parietal cells would prevent the absorption of vitamin B12 and lead to pernicious anemia.

Question 9

Where does fetal hematopoiesis occur?
A) In the gut
B) In the liver
C) In the bone marrow
D) In the thymus

Accepted Answer

Fetal hematopoiesis occurs primarily in the liver during the first trimester of gestation, and then gradually shifts to the bone marrow as it becomes functional in the second trimester. The gut and thymus also have hematopoietic potential, but to a much lesser extent compared to the liver and bone marrow.

Question 10

Polycythemia at birth may indicate:
A) hypoxia in utero.
B) dysfunctional bone marrow.
C) congenitally absent spleen.
D) dehydration in utero.

Accepted Answer

Polycythemia at birth is an increase in the number of red blood cells and may indicate that the fetus was not receiving enough oxygen in utero. This can cause the body to produce more red blood cells in an attempt to compensate for the low oxygen levels.

Question 11

Cells that destroy some types of tumor cells and some virus-infected cells without prior exposure are:
A) lymphocytes.
B) plasma cells.
C) megakaryocytes.
D) natural killer cells.

Accepted Answer

Natural killer (NK) cells are a type of lymphocyte that can recognize and destroy tumor cells and virus-infected cells without prior exposure. Plasma cells produce antibodies, but do not directly destroy infected or cancerous cells. Megakaryocytes are responsible for the production of platelets, and are not involved in immune responses.

Question 12

What is a consequence of a splenectomy?
A) There is an increased level of iron in the circulation.
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

The spleen helps filter defective or old red blood cells from the circulation. After a splenectomy, this filtering function is lost, leading to an increase in the number of defective cells in circulation.

Question 13

Recycling of iron from erythrocytes is made possible by:
A) transferrin.
B) hemosiderin.
C) apoferritin.
D) erythropoietin.

Accepted Answer

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.

Question 14

Which nutrients are necessary for the synthesis of DNA and maturation of erythrocytes? A) Protein and niacin B) Iron and vitamin B₆ (pyridoxine) C) Cobalamin (vitamin B₁₂)and folate D) Pantothenic acid and vitamin C

Accepted Answer

Cobalamin (vitamin B12) and folate are necessary for the synthesis of DNA and maturation of erythrocytes. Iron is also important for erythrocyte maturation, but it is not directly involved in DNA synthesis. Protein and niacin are not specifically involved in these processes, and pantothenic acid and vitamin C are not directly related to DNA synthesis or erythrocyte maturation.

Question 15

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

Accepted Answer

Mature erythrocytes are removed from the bloodstream by the spleen through a process called phagocytosis. The spleen identifies and removes old, damaged, or abnormal erythrocytes from circulation.

Question 16

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

Accepted Answer

Platelets have a short lifespan of approximately 10 days. After this time, they are removed by the liver and spleen.

Question 17

_____ is used to correct the chronic anemia associated with chronic renal failure. A) Colony-stimulating factor B) Erythropoietin C) Cobalamin (vitamin B₁₂) D) Folate E) Iron

Accepted Answer

Chronic renal failure can lead to a decreased production of erythropoietin, which is responsible for stimulating the production of red blood cells. Administration of erythropoietin can help correct the resulting anemia.

Question 18

What is the role of nitric oxide (NO)in hemostasis?
A) Nitric oxide (NO)stimulates the release of fibrinogen to maintain the platelet plug.
B) Nitric oxide (NO)stimulates the release of clotting factors V and VII.
C) Nitric oxide (NO)causes vasoconstriction and stimulates platelet aggregation.
D) Nitric oxide (NO)causes vasodilation and inhibits platelet adhesion and aggregation.

Accepted Answer

Nitric oxide (NO) causes vasodilation which leads to increased blood flow and decreased platelet adhesion and aggregation. This plays an important role in preventing unwanted blood clotting and maintaining healthy circulation.

Question 19

Which blood cells are produced when stem cells are stimulated by granulocyte-macrophage colony-stimulating factor (GM-CSF),interleukin 3 (Il-3),and granulocyte colony-stimulating factor (G-CSF)?
A) Neutrophils
B) Monocytes
C) Eosinophils
D) Erythrocytes

Accepted Answer

GM-CSF, IL-3, and G-CSF primarily stimulate the production of neutrophils from stem cells.

Question 20

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

Accepted Answer

Thromboxane A (TXA₂) plays a crucial role in the secretion stage of hemostasis by stimulating platelet aggregation. This leads to the formation of a platelet plug, which helps to prevent further blood loss from the injured site.

Quiz 25: Structure and Function of the Hematologic System

Where is iron absorbed?

Hemoglobin made from oxidized ferric iron (Fe¹¹¹) is called _____ and is unstable and lacks the ability to bind oxygen.

During an infection,lymph nodes enlarge and become tender because:

What is the role of plasmin in the clotting process?

How does the drug heparin act in hemostasis?

Which nutrients are necessary for the hemoglobin synthesis?

Which of the following shows a correct sequence in the development of erythrocytes?

Removing the stomach with its parietal cells would prevent the absorption of an essential nutrient necessary to prevent which type of anemia?

Where does fetal hematopoiesis occur?

Polycythemia at birth may indicate:

Cells that destroy some types of tumor cells and some virus-infected cells without prior exposure are:

What is a consequence of a splenectomy?

Recycling of iron from erythrocytes is made possible by:

Which nutrients are necessary for the synthesis of DNA and maturation of erythrocytes?

Where are mature erythrocytes removed from the bloodstream?

What is the life span of platelets?

_____ is used to correct the chronic anemia associated with chronic renal failure.

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

Which blood cells are produced when stem cells are stimulated by granulocyte-macrophage colony-stimulating factor (GM-CSF) ,interleukin 3 (Il-3) ,and granulocyte colony-stimulating factor (G-CSF) ?

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