NURS 5315 Exam 3 [2026] UPDATED ACTUAL | Question
and Answer | DETAILED ANSWER EXPLANATIONS
• What is the main reason for the sigmoidal shape of the oxygen-hemoglobin
dissociation curve?
A. Independent oxygen binding to hemoglobin
B. Hemoglobin saturation being fixed at 50%
C. Cooperative binding of oxygen molecules to hemoglobin
D. Linear increase in oxygen-binding with rising pO2 -✓✓ C. Cooperative binding of
oxygen molecules to hemoglobin
Rationale: The sigmoidal shape results from cooperative binding. When one oxygen
molecule binds to hemoglobin, it increases the affinity for subsequent oxygen
molecules.
• In which part of the oxygen-hemoglobin dissociation curve does hemoglobin have the
highest oxygen saturation?
A. Left side (low pO2)
B. Flat portion at the right (high pO2)
C. Steep portion (moderate pO2)
D. Middle portion of the curve -✓✓ B. Flat portion at the right (high pO2)
Rationale: The flat portion of the curve represents high pO2 conditions, such as in the
lungs, where hemoglobin is almost fully saturated with oxygen (~100% saturation).
• What is the clinical significance of the steep portion of the oxygen-hemoglobin
dissociation curve?
A. Minimal oxygen release at tissues
B. Enhanced oxygen uptake in the lungs
C. Large oxygen release with small pO2 changes
D. No oxygen release despite low pO2 -✓✓ C. Large oxygen release with small pO2
changes
Rationale: The steep portion allows for significant oxygen release from hemoglobin in
response to small drops in pO2, facilitating oxygen delivery to actively metabolizing
tissues.
• Which factor causes a rightward shift in the oxygen-hemoglobin dissociation curve?
A. Decreased temperature
B. Increased pH
C. Increased 2,3-BPG
D. Hypocapnia -✓✓ C. Increased 2,3-BPG
Rationale: Increased 2,3-BPG production lowers hemoglobin's affinity for oxygen,
shifting the curve to the right and promoting oxygen unloading to tissues.
,• What happens during a leftward shift of the oxygen-hemoglobin dissociation curve?
A. Easier oxygen release at tissues
B. Increased hemoglobin affinity for oxygen
C. Higher CO2 levels
D. Acidosis -✓✓ B. Increased hemoglobin affinity for oxygen
Rationale: A leftward shift means that hemoglobin binds oxygen more tightly, reducing
oxygen release to tissues but enhancing oxygen loading in the lungs.
• Which of the following conditions is likely to cause a leftward shift of the curve?
A. Fever
B. Alkalosis
C. Hypercapnia
D. Increased 2,3-BPG -✓✓ B. Alkalosis
Rationale: Alkalosis (higher pH) increases hemoglobin's affinity for oxygen, causing a
leftward shift in the oxygen-hemoglobin dissociation curve.
• What is the role of 2,3-Bisphosphoglycerate (2,3-BPG) in oxygen transport?
A. Enhances oxygen loading in the lungs
B. Stabilizes deoxygenated hemoglobin, promoting oxygen release
C. Shifts the curve to the left
D. Reduces oxygen delivery to tissues -✓✓ B. Stabilizes deoxygenated hemoglobin,
promoting oxygen release
Rationale: 2,3-BPG binds to deoxygenated hemoglobin, reducing its oxygen affinity and
facilitating oxygen release at the tissue level, causing a rightward shift.
• How does carbon monoxide (CO) poisoning affect the oxygen-hemoglobin dissociation
curve?
A. Shifts the curve to the right
B. No effect on the curve
C. Shifts the curve to the left, inhibiting oxygen release
D. Increases hemoglobin saturation -✓✓ C. Shifts the curve to the left, inhibiting oxygen
release
Rationale: CO binds with high affinity to hemoglobin, preventing oxygen binding and
shifting the curve to the left, which reduces oxygen release to tissues.
• Which condition promotes oxygen unloading to tissues during exercise?
A. Hypothermia
B. Increased CO2 production
C. Alkalosis
D. Decreased 2,3-BPG levels -✓✓ B. Increased CO2 production
,Rationale: During exercise, increased CO2 production and decreased pH shift the curve
to the right, facilitating oxygen release to tissues.
• What happens to oxygen delivery in tissues with a right-shifted oxygen-hemoglobin
dissociation curve?
A. Increased oxygen binding to hemoglobin
B. Enhanced oxygen unloading
C. Reduced tissue oxygenation
D. Stabilized oxygen saturation -✓✓ B. Enhanced oxygen unloading
Rationale: A rightward shift reduces hemoglobin's oxygen affinity, making it easier to
unload oxygen to tissues, which is essential during conditions like exercise or fever.
• Which laboratory finding is characteristic of microcytic, hypochromic anemia?
A. High MCV, low RDW
B. Low MCV, low MCHC
C. Normal MCV, normal MCHC
D. High MCHC, normal RDW -✓✓ B. Low MCV, low MCHC
Rationale: Microcytic, hypochromic anemia presents with a low mean corpuscular
volume (MCV) and low mean corpuscular hemoglobin concentration (MCHC). These
findings are typically seen in conditions like iron deficiency anemia and thalassemia.
• A patient presents with normal MCV and normal MCHC. Which type of anemia is most
likely?
A. Normocytic, normochromic anemia
B. Microcytic, hypochromic anemia
C. Macrocytic anemia
D. Pernicious anemia -✓✓ A. Normocytic, normochromic anemia
Rationale: Normocytic, normochromic anemia is characterized by normal MCV and
MCHC values. Common causes include acute blood loss, anemia of chronic disease,
and aplastic anemia.
• What is a common cause of macrocytic anemia?
A. Iron deficiency
B. Thalassemia
C. Folate deficiency
D. Acute blood loss -✓✓ C. Folate deficiency
Rationale: Macrocytic anemia is associated with a high MCV. Folate deficiency, along
with vitamin B12 deficiency and liver disease, is a common cause of this type of
anemia.
• A high RDW in the context of normocytic, normochromic anemia suggests which
condition?
, A. Acute blood loss
B. Aplastic anemia
C. Iron deficiency anemia
D. Hemolytic anemia -✓✓ D. Hemolytic anemia
Rationale: In normocytic, normochromic anemia, a high RDW can indicate variability in
red blood cell size, which is often seen in hemolytic anemia due to the presence of both
immature and mature red blood cells.
• A 45-year-old patient presents with fatigue and lab results showing low MCV, low
MCHC, and high RDW. What is the most likely diagnosis?
A. Acute blood loss
B. Iron deficiency anemia
C. Vitamin B12 deficiency
D. Hemolytic anemia -✓✓ B. Iron deficiency anemia
Rationale: Low MCV and MCHC are indicative of microcytic, hypochromic anemia. High
RDW suggests increased variability in red blood cell size, which is characteristic of iron
deficiency anemia.
• What is the primary mechanism behind anemia of chronic illness?
A. Decreased iron intake
B. Increased erythropoietin production
C. Inhibition of erythropoietin and increased hepcidin levels
D. Excessive blood loss -✓✓ C. Inhibition of erythropoietin and increased hepcidin
levels
Rationale: Proinflammatory cytokines in chronic illness inhibit erythropoietin production
and increase hepcidin levels, reducing iron absorption and iron release despite normal
or high iron stores.
• Which iron study pattern is characteristic of anemia of chronic illness?
A. Low serum iron, low ferritin, high TIBC
B. High serum iron, low TIBC, high transferrin saturation
C. Low serum iron, high ferritin, low or normal TIBC
D. Normal serum iron, low ferritin, high TIBC -✓✓ C. Low serum iron, high ferritin, low or
normal TIBC
Rationale: Anemia of chronic illness typically presents with low serum iron, high ferritin
(due to inflammation), and low or normal TIBC due to reduced iron availability despite
adequate stores.
• Which laboratory finding is typically elevated in hemolytic anemia?
A. Decreased bilirubin
B. Elevated haptoglobin
C. Elevated bilirubin
and Answer | DETAILED ANSWER EXPLANATIONS
• What is the main reason for the sigmoidal shape of the oxygen-hemoglobin
dissociation curve?
A. Independent oxygen binding to hemoglobin
B. Hemoglobin saturation being fixed at 50%
C. Cooperative binding of oxygen molecules to hemoglobin
D. Linear increase in oxygen-binding with rising pO2 -✓✓ C. Cooperative binding of
oxygen molecules to hemoglobin
Rationale: The sigmoidal shape results from cooperative binding. When one oxygen
molecule binds to hemoglobin, it increases the affinity for subsequent oxygen
molecules.
• In which part of the oxygen-hemoglobin dissociation curve does hemoglobin have the
highest oxygen saturation?
A. Left side (low pO2)
B. Flat portion at the right (high pO2)
C. Steep portion (moderate pO2)
D. Middle portion of the curve -✓✓ B. Flat portion at the right (high pO2)
Rationale: The flat portion of the curve represents high pO2 conditions, such as in the
lungs, where hemoglobin is almost fully saturated with oxygen (~100% saturation).
• What is the clinical significance of the steep portion of the oxygen-hemoglobin
dissociation curve?
A. Minimal oxygen release at tissues
B. Enhanced oxygen uptake in the lungs
C. Large oxygen release with small pO2 changes
D. No oxygen release despite low pO2 -✓✓ C. Large oxygen release with small pO2
changes
Rationale: The steep portion allows for significant oxygen release from hemoglobin in
response to small drops in pO2, facilitating oxygen delivery to actively metabolizing
tissues.
• Which factor causes a rightward shift in the oxygen-hemoglobin dissociation curve?
A. Decreased temperature
B. Increased pH
C. Increased 2,3-BPG
D. Hypocapnia -✓✓ C. Increased 2,3-BPG
Rationale: Increased 2,3-BPG production lowers hemoglobin's affinity for oxygen,
shifting the curve to the right and promoting oxygen unloading to tissues.
,• What happens during a leftward shift of the oxygen-hemoglobin dissociation curve?
A. Easier oxygen release at tissues
B. Increased hemoglobin affinity for oxygen
C. Higher CO2 levels
D. Acidosis -✓✓ B. Increased hemoglobin affinity for oxygen
Rationale: A leftward shift means that hemoglobin binds oxygen more tightly, reducing
oxygen release to tissues but enhancing oxygen loading in the lungs.
• Which of the following conditions is likely to cause a leftward shift of the curve?
A. Fever
B. Alkalosis
C. Hypercapnia
D. Increased 2,3-BPG -✓✓ B. Alkalosis
Rationale: Alkalosis (higher pH) increases hemoglobin's affinity for oxygen, causing a
leftward shift in the oxygen-hemoglobin dissociation curve.
• What is the role of 2,3-Bisphosphoglycerate (2,3-BPG) in oxygen transport?
A. Enhances oxygen loading in the lungs
B. Stabilizes deoxygenated hemoglobin, promoting oxygen release
C. Shifts the curve to the left
D. Reduces oxygen delivery to tissues -✓✓ B. Stabilizes deoxygenated hemoglobin,
promoting oxygen release
Rationale: 2,3-BPG binds to deoxygenated hemoglobin, reducing its oxygen affinity and
facilitating oxygen release at the tissue level, causing a rightward shift.
• How does carbon monoxide (CO) poisoning affect the oxygen-hemoglobin dissociation
curve?
A. Shifts the curve to the right
B. No effect on the curve
C. Shifts the curve to the left, inhibiting oxygen release
D. Increases hemoglobin saturation -✓✓ C. Shifts the curve to the left, inhibiting oxygen
release
Rationale: CO binds with high affinity to hemoglobin, preventing oxygen binding and
shifting the curve to the left, which reduces oxygen release to tissues.
• Which condition promotes oxygen unloading to tissues during exercise?
A. Hypothermia
B. Increased CO2 production
C. Alkalosis
D. Decreased 2,3-BPG levels -✓✓ B. Increased CO2 production
,Rationale: During exercise, increased CO2 production and decreased pH shift the curve
to the right, facilitating oxygen release to tissues.
• What happens to oxygen delivery in tissues with a right-shifted oxygen-hemoglobin
dissociation curve?
A. Increased oxygen binding to hemoglobin
B. Enhanced oxygen unloading
C. Reduced tissue oxygenation
D. Stabilized oxygen saturation -✓✓ B. Enhanced oxygen unloading
Rationale: A rightward shift reduces hemoglobin's oxygen affinity, making it easier to
unload oxygen to tissues, which is essential during conditions like exercise or fever.
• Which laboratory finding is characteristic of microcytic, hypochromic anemia?
A. High MCV, low RDW
B. Low MCV, low MCHC
C. Normal MCV, normal MCHC
D. High MCHC, normal RDW -✓✓ B. Low MCV, low MCHC
Rationale: Microcytic, hypochromic anemia presents with a low mean corpuscular
volume (MCV) and low mean corpuscular hemoglobin concentration (MCHC). These
findings are typically seen in conditions like iron deficiency anemia and thalassemia.
• A patient presents with normal MCV and normal MCHC. Which type of anemia is most
likely?
A. Normocytic, normochromic anemia
B. Microcytic, hypochromic anemia
C. Macrocytic anemia
D. Pernicious anemia -✓✓ A. Normocytic, normochromic anemia
Rationale: Normocytic, normochromic anemia is characterized by normal MCV and
MCHC values. Common causes include acute blood loss, anemia of chronic disease,
and aplastic anemia.
• What is a common cause of macrocytic anemia?
A. Iron deficiency
B. Thalassemia
C. Folate deficiency
D. Acute blood loss -✓✓ C. Folate deficiency
Rationale: Macrocytic anemia is associated with a high MCV. Folate deficiency, along
with vitamin B12 deficiency and liver disease, is a common cause of this type of
anemia.
• A high RDW in the context of normocytic, normochromic anemia suggests which
condition?
, A. Acute blood loss
B. Aplastic anemia
C. Iron deficiency anemia
D. Hemolytic anemia -✓✓ D. Hemolytic anemia
Rationale: In normocytic, normochromic anemia, a high RDW can indicate variability in
red blood cell size, which is often seen in hemolytic anemia due to the presence of both
immature and mature red blood cells.
• A 45-year-old patient presents with fatigue and lab results showing low MCV, low
MCHC, and high RDW. What is the most likely diagnosis?
A. Acute blood loss
B. Iron deficiency anemia
C. Vitamin B12 deficiency
D. Hemolytic anemia -✓✓ B. Iron deficiency anemia
Rationale: Low MCV and MCHC are indicative of microcytic, hypochromic anemia. High
RDW suggests increased variability in red blood cell size, which is characteristic of iron
deficiency anemia.
• What is the primary mechanism behind anemia of chronic illness?
A. Decreased iron intake
B. Increased erythropoietin production
C. Inhibition of erythropoietin and increased hepcidin levels
D. Excessive blood loss -✓✓ C. Inhibition of erythropoietin and increased hepcidin
levels
Rationale: Proinflammatory cytokines in chronic illness inhibit erythropoietin production
and increase hepcidin levels, reducing iron absorption and iron release despite normal
or high iron stores.
• Which iron study pattern is characteristic of anemia of chronic illness?
A. Low serum iron, low ferritin, high TIBC
B. High serum iron, low TIBC, high transferrin saturation
C. Low serum iron, high ferritin, low or normal TIBC
D. Normal serum iron, low ferritin, high TIBC -✓✓ C. Low serum iron, high ferritin, low or
normal TIBC
Rationale: Anemia of chronic illness typically presents with low serum iron, high ferritin
(due to inflammation), and low or normal TIBC due to reduced iron availability despite
adequate stores.
• Which laboratory finding is typically elevated in hemolytic anemia?
A. Decreased bilirubin
B. Elevated haptoglobin
C. Elevated bilirubin
