NURS 323 EXAM 3 | 2025/2026 UPDATE | QUESTIONS AND ANSWERS |
WITH COMPLETE SOLUTION
Instructions: Choose the single best answer for each of the following questions.
1. What is the maximum number of oxygen molecules that a single molecule of adult
hemoglobin (HbA) can transport?
A) One
B) Two
C) Four
D) Eight
Correct Answer: C) Four
Rationale: A hemoglobin molecule is composed of four globin chains (two alpha, two beta), and
each chain contains one heme group. Each heme group can bind one molecule of oxygen,
allowing a single hemoglobin molecule to carry a total of four oxygen molecules.
2. The component of hemoglobin that contains iron and is responsible for binding oxygen is
called:
A) Globin
B) Transferrin
C) Ferritin
D) Heme
Correct Answer: D) Heme
Rationale: A heme group is an iron-protoporphyrin complex. The iron atom at the center of the
heme group is the site of reversible oxygen binding.
3. The adult form of hemoglobin (HbA) is composed of which combination of globin
chains?
A) Two alpha chains and two gamma chains
B) Four alpha chains
C) Two alpha chains and two beta chains
D) Four beta chains
Correct Answer: C) Two alpha chains and two beta chains
Rationale: Normal adult hemoglobin is a tetramer consisting of two alpha-globin chains and two
beta-globin chains. Fetal hemoglobin (HbF) consists of two alpha and two gamma chains.
4. For oxygen to bind to hemoglobin, the iron in the heme group must be in which state?
A) Oxidized ferric iron (Fe³⁺)
B) Reduced ferrous iron (Fe²⁺)
C) Bound to transferrin
D) Stored as ferritin
,[Type here]
Correct Answer: B) Reduced ferrous iron (Fe²⁺)
Rationale: Only the reduced ferrous (Fe²⁺) state of iron can reversibly bind an oxygen molecule.
When iron is oxidized to the ferric (Fe³⁺) state, the resulting molecule is called methemoglobin
and it cannot carry oxygen.
5. Dietary iron is primarily absorbed in which part of the gastrointestinal tract?
A) Stomach and esophagus
B) Duodenum and proximal jejunum
C) Ileum and cecum
D) Colon and rectum
Correct Answer: B) Duodenum and proximal jejunum
Rationale: The acidic environment of the proximal small intestine helps to keep iron in its more
soluble ferrous (Fe²⁺) state, facilitating its absorption by the enterocytes of the duodenum and
upper jejunum.
6. Iron is transported in the bloodstream bound to which specific protein?
A) Hemoglobin
B) Ferritin
C) Transferrin
D) Albumin
Correct Answer: C) Transferrin
Rationale: Transferrin is the primary iron-transport protein in the blood. It picks up iron from
the intestine or from sites of hemoglobin breakdown and delivers it to tissues that need it, most
importantly the bone marrow.
7. The major storage form of iron in the body, found primarily in the liver, is:
A) Transferrin
B) Heme
C) Ferritin
D) Hemosiderin
Correct Answer: C) Ferritin
Rationale: Ferritin is a large, spherical protein that can store thousands of iron atoms in a non-
toxic form within cells. The liver is the main storage site. Hemosiderin is a less soluble,
aggregated form of stored iron.
8. After an aged red blood cell is removed from circulation and broken down in the spleen,
what happens to the iron from its hemoglobin?
A) It is excreted in the bile.
B) It is permanently stored in the spleen.
C) It is reabsorbed into the bloodstream and recycled.
D) It is converted to bilirubin.
,[Type here]
Correct Answer: C) It is reabsorbed into the bloodstream and recycled.
Rationale: The body has a very efficient iron recycling system. Macrophages in the spleen break
down old RBCs, release the iron from the heme, and return it to the plasma, where it binds to
transferrin to be reused for new red blood cell synthesis.
9. The physiological process that causes bleeding to stop is known as:
A) Fibrinolysis
B) Hemostasis
C) Hematopoiesis
D) Hemolysis
Correct Answer: B) Hemostasis
Rationale: Hemostasis is the process of forming a clot to seal an injured blood vessel and
prevent blood loss. It is a complex process involving platelets, clotting factors, and the
vasculature.
10. Which of the following is NOT a primary function of platelets in hemostasis?
A) Initiating vasoconstriction.
B) Forming a primary platelet plug.
C) Activating the coagulation cascade.
D) Dissolving the fibrin clot (fibrinolysis).
Correct Answer: D) Dissolving the fibrin clot (fibrinolysis).
Rationale: Platelets are crucial for initiating and forming the clot. The dissolution of the clot, or
fibrinolysis, is a later process mediated by plasmin, which is activated from plasminogen.
11. What are the four major steps in the formation of a platelet plug?
A) Vasoconstriction, Adhesion, Aggregation, Retraction
B) Adhesion, Aggregation, Activation, Fibrinolysis
C) Adhesion, Release Reaction, Aggregation, Plug Formation
D) Initiation, Amplification, Propagation, Stabilization
Correct Answer: C) Adhesion, Release Reaction, Aggregation, Plug Formation
Rationale: The formation of the primary hemostatic plug follows a specific sequence: (1)
platelets adhere to the exposed subendothelial collagen, (2) this triggers the release of granules
(release reaction), which (3) recruits more platelets to the site (aggregation), leading to the (4)
formation of the plug.
12. Following an injury to a blood vessel, the immediate vascular response is:
A) A prolonged period of vasodilation.
B) A brief vasodilation followed by a prolonged vasoconstriction (vasospasm).
C) A sustained vasoconstriction with no initial vasodilation.
D) No change in vessel diameter.
, [Type here]
Correct Answer: B) A brief vasodilation followed by a prolonged vasoconstriction
(vasospasm).
Rationale: The initial brief vasodilation allows blood and clotting components to reach the area,
but this is immediately followed by a neurally and chemically mediated vasoconstriction to limit
blood flow and loss from the damaged vessel.
13. The formation of a stable, cross-linked fibrin clot is the end product of the:
A) Platelet aggregation pathway
B) Coagulation cascade
C) Fibrinolytic pathway
D) Vasoconstriction reflex
Correct Answer: B) Coagulation cascade
Rationale: The coagulation cascade is a series of enzymatic reactions involving various clotting
factors. The final step is the conversion of soluble fibrinogen into insoluble fibrin strands, which
stabilize the primary platelet plug.
14. What is the role of von Willebrand factor (vWF) in primary hemostasis?
A) It converts prothrombin to thrombin.
B) It acts as a bridge, connecting platelets to the exposed subendothelial collagen.
C) It dissolves the fibrin clot.
D) It causes vasoconstriction of the injured vessel.
Correct Answer: B) It acts as a bridge, connecting platelets to the exposed subendothelial
collagen.
Rationale: vWF is essential for the first step of platelet plug formation, platelet adhesion. It
binds to the exposed collagen at the site of injury and then to a specific receptor (GPIb) on the
platelet surface, effectively anchoring the platelets to the vessel wall.
15. A patient with Von Willebrand Disease (vWD) has impaired platelet adhesion. Which of
the following lab results would be expected?
A) A low platelet count.
B) A prolonged bleeding time.
C) A prolonged prothrombin time (PT).
D) A decreased Factor VIII level with a normal PTT.
Correct Answer: B) A prolonged bleeding time.
Rationale: The bleeding time test measures the time it takes for a standardized skin incision to
stop bleeding, which is a test of primary hemostasis (platelet function). Since platelet adhesion is
defective in vWD, the bleeding time is typically prolonged. The platelet count is normal.
16. Which of the following is true about the inheritance pattern of the most common form
of Von Willebrand Disease?
A) It is autosomal dominant.
WITH COMPLETE SOLUTION
Instructions: Choose the single best answer for each of the following questions.
1. What is the maximum number of oxygen molecules that a single molecule of adult
hemoglobin (HbA) can transport?
A) One
B) Two
C) Four
D) Eight
Correct Answer: C) Four
Rationale: A hemoglobin molecule is composed of four globin chains (two alpha, two beta), and
each chain contains one heme group. Each heme group can bind one molecule of oxygen,
allowing a single hemoglobin molecule to carry a total of four oxygen molecules.
2. The component of hemoglobin that contains iron and is responsible for binding oxygen is
called:
A) Globin
B) Transferrin
C) Ferritin
D) Heme
Correct Answer: D) Heme
Rationale: A heme group is an iron-protoporphyrin complex. The iron atom at the center of the
heme group is the site of reversible oxygen binding.
3. The adult form of hemoglobin (HbA) is composed of which combination of globin
chains?
A) Two alpha chains and two gamma chains
B) Four alpha chains
C) Two alpha chains and two beta chains
D) Four beta chains
Correct Answer: C) Two alpha chains and two beta chains
Rationale: Normal adult hemoglobin is a tetramer consisting of two alpha-globin chains and two
beta-globin chains. Fetal hemoglobin (HbF) consists of two alpha and two gamma chains.
4. For oxygen to bind to hemoglobin, the iron in the heme group must be in which state?
A) Oxidized ferric iron (Fe³⁺)
B) Reduced ferrous iron (Fe²⁺)
C) Bound to transferrin
D) Stored as ferritin
,[Type here]
Correct Answer: B) Reduced ferrous iron (Fe²⁺)
Rationale: Only the reduced ferrous (Fe²⁺) state of iron can reversibly bind an oxygen molecule.
When iron is oxidized to the ferric (Fe³⁺) state, the resulting molecule is called methemoglobin
and it cannot carry oxygen.
5. Dietary iron is primarily absorbed in which part of the gastrointestinal tract?
A) Stomach and esophagus
B) Duodenum and proximal jejunum
C) Ileum and cecum
D) Colon and rectum
Correct Answer: B) Duodenum and proximal jejunum
Rationale: The acidic environment of the proximal small intestine helps to keep iron in its more
soluble ferrous (Fe²⁺) state, facilitating its absorption by the enterocytes of the duodenum and
upper jejunum.
6. Iron is transported in the bloodstream bound to which specific protein?
A) Hemoglobin
B) Ferritin
C) Transferrin
D) Albumin
Correct Answer: C) Transferrin
Rationale: Transferrin is the primary iron-transport protein in the blood. It picks up iron from
the intestine or from sites of hemoglobin breakdown and delivers it to tissues that need it, most
importantly the bone marrow.
7. The major storage form of iron in the body, found primarily in the liver, is:
A) Transferrin
B) Heme
C) Ferritin
D) Hemosiderin
Correct Answer: C) Ferritin
Rationale: Ferritin is a large, spherical protein that can store thousands of iron atoms in a non-
toxic form within cells. The liver is the main storage site. Hemosiderin is a less soluble,
aggregated form of stored iron.
8. After an aged red blood cell is removed from circulation and broken down in the spleen,
what happens to the iron from its hemoglobin?
A) It is excreted in the bile.
B) It is permanently stored in the spleen.
C) It is reabsorbed into the bloodstream and recycled.
D) It is converted to bilirubin.
,[Type here]
Correct Answer: C) It is reabsorbed into the bloodstream and recycled.
Rationale: The body has a very efficient iron recycling system. Macrophages in the spleen break
down old RBCs, release the iron from the heme, and return it to the plasma, where it binds to
transferrin to be reused for new red blood cell synthesis.
9. The physiological process that causes bleeding to stop is known as:
A) Fibrinolysis
B) Hemostasis
C) Hematopoiesis
D) Hemolysis
Correct Answer: B) Hemostasis
Rationale: Hemostasis is the process of forming a clot to seal an injured blood vessel and
prevent blood loss. It is a complex process involving platelets, clotting factors, and the
vasculature.
10. Which of the following is NOT a primary function of platelets in hemostasis?
A) Initiating vasoconstriction.
B) Forming a primary platelet plug.
C) Activating the coagulation cascade.
D) Dissolving the fibrin clot (fibrinolysis).
Correct Answer: D) Dissolving the fibrin clot (fibrinolysis).
Rationale: Platelets are crucial for initiating and forming the clot. The dissolution of the clot, or
fibrinolysis, is a later process mediated by plasmin, which is activated from plasminogen.
11. What are the four major steps in the formation of a platelet plug?
A) Vasoconstriction, Adhesion, Aggregation, Retraction
B) Adhesion, Aggregation, Activation, Fibrinolysis
C) Adhesion, Release Reaction, Aggregation, Plug Formation
D) Initiation, Amplification, Propagation, Stabilization
Correct Answer: C) Adhesion, Release Reaction, Aggregation, Plug Formation
Rationale: The formation of the primary hemostatic plug follows a specific sequence: (1)
platelets adhere to the exposed subendothelial collagen, (2) this triggers the release of granules
(release reaction), which (3) recruits more platelets to the site (aggregation), leading to the (4)
formation of the plug.
12. Following an injury to a blood vessel, the immediate vascular response is:
A) A prolonged period of vasodilation.
B) A brief vasodilation followed by a prolonged vasoconstriction (vasospasm).
C) A sustained vasoconstriction with no initial vasodilation.
D) No change in vessel diameter.
, [Type here]
Correct Answer: B) A brief vasodilation followed by a prolonged vasoconstriction
(vasospasm).
Rationale: The initial brief vasodilation allows blood and clotting components to reach the area,
but this is immediately followed by a neurally and chemically mediated vasoconstriction to limit
blood flow and loss from the damaged vessel.
13. The formation of a stable, cross-linked fibrin clot is the end product of the:
A) Platelet aggregation pathway
B) Coagulation cascade
C) Fibrinolytic pathway
D) Vasoconstriction reflex
Correct Answer: B) Coagulation cascade
Rationale: The coagulation cascade is a series of enzymatic reactions involving various clotting
factors. The final step is the conversion of soluble fibrinogen into insoluble fibrin strands, which
stabilize the primary platelet plug.
14. What is the role of von Willebrand factor (vWF) in primary hemostasis?
A) It converts prothrombin to thrombin.
B) It acts as a bridge, connecting platelets to the exposed subendothelial collagen.
C) It dissolves the fibrin clot.
D) It causes vasoconstriction of the injured vessel.
Correct Answer: B) It acts as a bridge, connecting platelets to the exposed subendothelial
collagen.
Rationale: vWF is essential for the first step of platelet plug formation, platelet adhesion. It
binds to the exposed collagen at the site of injury and then to a specific receptor (GPIb) on the
platelet surface, effectively anchoring the platelets to the vessel wall.
15. A patient with Von Willebrand Disease (vWD) has impaired platelet adhesion. Which of
the following lab results would be expected?
A) A low platelet count.
B) A prolonged bleeding time.
C) A prolonged prothrombin time (PT).
D) A decreased Factor VIII level with a normal PTT.
Correct Answer: B) A prolonged bleeding time.
Rationale: The bleeding time test measures the time it takes for a standardized skin incision to
stop bleeding, which is a test of primary hemostasis (platelet function). Since platelet adhesion is
defective in vWD, the bleeding time is typically prolonged. The platelet count is normal.
16. Which of the following is true about the inheritance pattern of the most common form
of Von Willebrand Disease?
A) It is autosomal dominant.
