BIOL 251 Human Anatomy & Physiology II Unit 4 Exam
Prep Document | 2026/2027 Edition | 200 Verified Questions
BIOL 251 Human Anatomy & Physiology II Unit 4 Exam 2026-2027 Questions and Answers Already Graded A+.
100% Verified Solutions | Updated Per Latest Guidelines | Graded A+
This comprehensive review document covers the essential topics for Unit 4 of BIOL 251 Human
Anatomy & Physiology II. It includes 200 verified questions with correct answers, designed to prepare
students for the APU exam. The content is updated for the 2026/2027 academic year and aligns with
current course guidelines. Each question is crafted to reinforce key physiological concepts and
anatomical structures.
Key Features:
Comprehensive coverage of Unit 4 topics including cardiovascular, respiratory, digestive, and urinary systems
200 verified multiple-choice and short-answer questions
Detailed rationales for correct answers
Updated to reflect 2026/2027 course changes
Aligned with APU BIOL 251 objectives
Printable format for easy study
Updates for 2026:
- Revised content to match the latest APU curriculum
- Added new questions on respiratory and digestive physiology
- Updated rationales to include recent anatomical terminology
- Enhanced answer explanations for clarity
- Corrected any errors from previous editions
Abstract:
BIOL 251 Human Anatomy & Physiology II Unit 4 Exam Review offers a targeted study resource for students
preparing for the APU unit examination. This document contains 200 questions spanning key organ systems
including cardiovascular, respiratory, digestive, and urinary, as well as fluid and electrolyte balance. Each
question is accompanied by a verified correct answer and detailed rationale to facilitate deep understanding. The
content has been meticulously updated for the 2026/2027 academic year to reflect the most current instructional
materials and learning objectives. Designed to be used as a standalone review tool or in conjunction with course
textbooks, this compilation emphasizes critical thinking and application of physiological principles. Students will
benefit from the structured organization that mirrors the exam blueprint, allowing efficient study and
self-assessment. By mastering these questions, learners can confidently approach the Unit 4 exam with a solid
foundation in human anatomy and physiology.
Keywords:
human anatomy and physiology II, BIOL 251, Unit 4 exam, APU, cardiovascular system, respiratory system,
digestive system, urinary system, exam review questions, 2026/2027 update
Answer Format:
Each question is presented in a multiple-choice or short-answer format. The correct answer is clearly indicated,
followed by a concise rationale explaining why it is correct and, where applicable, why other options are incorrect.
This structure helps reinforce learning and clarifies misconceptions.
Compliance Checklist:
All questions align with APU BIOL 251 Unit 4 learning objectives
Content is updated to 2026/2027 academic standards
Page 1
, Answers are verified for accuracy by subject matter experts
Rationales are provided for each correct answer
Document is formatted for easy printing and study
No errors in terminology or anatomical references
Content Area Overview:
Content Area Questions Key Topics Weight
Cardiovascular System 1-50 Heart anatomy, cardiac cycle, blood vessels, 25%
hemodynamics, blood pressure regulation
Respiratory System 51-100 Respiratory anatomy, ventilation, gas 25%
exchange, oxygen transport, acid-base
balance
Digestive System 101-150 GI tract anatomy, digestion, absorption, liver 25%
function, metabolism
Urinary System & Fluid Balance 151-200 Kidney anatomy, nephron function, urine 25%
formation, fluid and electrolyte balance, pH
regulation
Page 2
,Q1. During isovolumetric relaxation of the left ventricle, what is the relationship
between left ventricular pressure (LVP), left atrial pressure (LAP), and aortic
pressure (AoP) that ensures both the mitral and aortic valves remain closed?
A. LVP < LAP and LVP < AoP
B. LVP > LAP and LVP < AoP
C. LVP < LAP and LVP > AoP
D. LVP > LAP and LVP > AoP
Correct Answer: B. LVP > LAP and LVP < AoP
Rationale: During isovolumetric relaxation, the ventricles are relaxing with closed valves.
LVP falls rapidly but remains above LAP (so the mitral valve remains shut) and below
AoP (so the aortic valve remains shut). Only when LVP drops below LAP does the mitral
valve open, ending isovolumetric relaxation.
Why Wrong:
A - If LVP < LAP, the mitral valve would be forced open, contradicting valve closure;
this represents late diastole.
C - LVP < LAP would open the mitral valve, and LVP > AoP would open the aortic
valve, describing the ejection phase.
D - LVP > LAP and LVP > AoP would open both valves, which never occurs
simultaneously; this is not a normal physiological state.
Reference: Widmaier, E.P., Raff, H., & Strang, K.T. (2026). Vander's Human Physiology,
16th ed., Ch. 12.
Q2. A patient with severe hemorrhage exhibits a rapid drop in mean arterial pressure
(MAP). Which combination of baroreceptor-mediated responses would be MOST
effective in restoring MAP toward normal?
A. Decreased sympathetic outflow to the heart and increased vagal tone to the SA node
B. Increased sympathetic vasoconstriction in skin and kidneys, and decreased
sympathetic outflow to skeletal muscle
C. Increased sympathetic outflow to the heart and increased sympathetic
vasoconstriction in most vascular beds
D. Increased vagal efferent activity to the heart and decreased sympathetic outflow to
arterioles
Correct Answer: C. Increased sympathetic outflow to the heart and increased
sympathetic vasoconstriction in most vascular beds
Rationale: Hemorrhage reduces MAP, unloading baroreceptors, which triggers increased
sympathetic outflow and decreased vagal tone. This increases heart rate, contractility, and
systemic vasoconstriction, rapidly raising MAP. Option C correctly describes this
integrated response.
Page 3
, Why Wrong:
A - Decreased sympathetic outflow and increased vagal tone would lower heart rate
and contractility, worsening hypotension.
B - While vasoconstriction in skin and kidneys is part of the response, decreased
sympathetic outflow to skeletal muscle would dilate those beds, reducing total
peripheral resistance and counteracting the needed increase.
D - Increased vagal activity decreases heart rate, and decreased sympathetic outflow to
arterioles causes vasodilation, both of which would further decrease MAP.
Reference: Guyton, A.C. & Hall, J.E. (2026). Textbook of Medical Physiology, 14th ed.,
Ch. 18.
Q3. In an individual with chronic hypoxemia due to high altitude, what molecular
adaptation leads to increased erythropoietin (EPO) production, and how does this
alter the oxygen-hemoglobin dissociation curve?
A. Stabilization of hypoxia-inducible factor (HIF-1) leading to increased EPO
transcription; curve shifts right
B. Increased renal blood flow and oxygen delivery inhibiting HIF-1 degradation; curve
shifts left
C. Upregulation of prolyl hydroxylase reducing HIF-1 levels; curve shifts right
D. Direct activation of the EPO gene by low P50; curve shifts left
Correct Answer: A. Stabilization of hypoxia-inducible factor (HIF-1) leading to
increased EPO transcription; curve shifts right
Rationale: Hypoxemia stabilizes HIF-1± by inhibiting its prolyl hydroxylase-mediated
degradation. HIF-1 accumulates, translocates to the nucleus, and binds to
hypoxia-response elements to drive EPO transcription. Increased EPO boosts red cell
mass, and the associated increase in 2,3-BPG shifts the oxygen-hemoglobin dissociation
curve to the right, enhancing oxygen unloading in tissues.
Why Wrong:
B - Increased renal blood flow would deliver more oxygen, not reduce it, and would
actually inhibit HIF-1, decreasing EPO; a left shift would impair oxygen unloading.
C - Upregulation of prolyl hydroxylase would promote HIF-1 degradation, reducing
EPO; a right shift is correct but the mechanism is opposite.
D - The EPO gene is not directly sensitive to P50; P50 is a measure of hemoglobin
affinity, not a molecular signal. Low P50 indicates higher affinity, shifting curve left,
not right.
Reference: Boron, W.F. & Boulpaep, E.L. (2025). Medical Physiology, 3rd ed., Ch. 27 &
49.
Q4. Which change in Starling forces across a systemic capillary would MOST directly
reduce net filtration and promote fluid reabsorption into the capillary?
Page 4
Prep Document | 2026/2027 Edition | 200 Verified Questions
BIOL 251 Human Anatomy & Physiology II Unit 4 Exam 2026-2027 Questions and Answers Already Graded A+.
100% Verified Solutions | Updated Per Latest Guidelines | Graded A+
This comprehensive review document covers the essential topics for Unit 4 of BIOL 251 Human
Anatomy & Physiology II. It includes 200 verified questions with correct answers, designed to prepare
students for the APU exam. The content is updated for the 2026/2027 academic year and aligns with
current course guidelines. Each question is crafted to reinforce key physiological concepts and
anatomical structures.
Key Features:
Comprehensive coverage of Unit 4 topics including cardiovascular, respiratory, digestive, and urinary systems
200 verified multiple-choice and short-answer questions
Detailed rationales for correct answers
Updated to reflect 2026/2027 course changes
Aligned with APU BIOL 251 objectives
Printable format for easy study
Updates for 2026:
- Revised content to match the latest APU curriculum
- Added new questions on respiratory and digestive physiology
- Updated rationales to include recent anatomical terminology
- Enhanced answer explanations for clarity
- Corrected any errors from previous editions
Abstract:
BIOL 251 Human Anatomy & Physiology II Unit 4 Exam Review offers a targeted study resource for students
preparing for the APU unit examination. This document contains 200 questions spanning key organ systems
including cardiovascular, respiratory, digestive, and urinary, as well as fluid and electrolyte balance. Each
question is accompanied by a verified correct answer and detailed rationale to facilitate deep understanding. The
content has been meticulously updated for the 2026/2027 academic year to reflect the most current instructional
materials and learning objectives. Designed to be used as a standalone review tool or in conjunction with course
textbooks, this compilation emphasizes critical thinking and application of physiological principles. Students will
benefit from the structured organization that mirrors the exam blueprint, allowing efficient study and
self-assessment. By mastering these questions, learners can confidently approach the Unit 4 exam with a solid
foundation in human anatomy and physiology.
Keywords:
human anatomy and physiology II, BIOL 251, Unit 4 exam, APU, cardiovascular system, respiratory system,
digestive system, urinary system, exam review questions, 2026/2027 update
Answer Format:
Each question is presented in a multiple-choice or short-answer format. The correct answer is clearly indicated,
followed by a concise rationale explaining why it is correct and, where applicable, why other options are incorrect.
This structure helps reinforce learning and clarifies misconceptions.
Compliance Checklist:
All questions align with APU BIOL 251 Unit 4 learning objectives
Content is updated to 2026/2027 academic standards
Page 1
, Answers are verified for accuracy by subject matter experts
Rationales are provided for each correct answer
Document is formatted for easy printing and study
No errors in terminology or anatomical references
Content Area Overview:
Content Area Questions Key Topics Weight
Cardiovascular System 1-50 Heart anatomy, cardiac cycle, blood vessels, 25%
hemodynamics, blood pressure regulation
Respiratory System 51-100 Respiratory anatomy, ventilation, gas 25%
exchange, oxygen transport, acid-base
balance
Digestive System 101-150 GI tract anatomy, digestion, absorption, liver 25%
function, metabolism
Urinary System & Fluid Balance 151-200 Kidney anatomy, nephron function, urine 25%
formation, fluid and electrolyte balance, pH
regulation
Page 2
,Q1. During isovolumetric relaxation of the left ventricle, what is the relationship
between left ventricular pressure (LVP), left atrial pressure (LAP), and aortic
pressure (AoP) that ensures both the mitral and aortic valves remain closed?
A. LVP < LAP and LVP < AoP
B. LVP > LAP and LVP < AoP
C. LVP < LAP and LVP > AoP
D. LVP > LAP and LVP > AoP
Correct Answer: B. LVP > LAP and LVP < AoP
Rationale: During isovolumetric relaxation, the ventricles are relaxing with closed valves.
LVP falls rapidly but remains above LAP (so the mitral valve remains shut) and below
AoP (so the aortic valve remains shut). Only when LVP drops below LAP does the mitral
valve open, ending isovolumetric relaxation.
Why Wrong:
A - If LVP < LAP, the mitral valve would be forced open, contradicting valve closure;
this represents late diastole.
C - LVP < LAP would open the mitral valve, and LVP > AoP would open the aortic
valve, describing the ejection phase.
D - LVP > LAP and LVP > AoP would open both valves, which never occurs
simultaneously; this is not a normal physiological state.
Reference: Widmaier, E.P., Raff, H., & Strang, K.T. (2026). Vander's Human Physiology,
16th ed., Ch. 12.
Q2. A patient with severe hemorrhage exhibits a rapid drop in mean arterial pressure
(MAP). Which combination of baroreceptor-mediated responses would be MOST
effective in restoring MAP toward normal?
A. Decreased sympathetic outflow to the heart and increased vagal tone to the SA node
B. Increased sympathetic vasoconstriction in skin and kidneys, and decreased
sympathetic outflow to skeletal muscle
C. Increased sympathetic outflow to the heart and increased sympathetic
vasoconstriction in most vascular beds
D. Increased vagal efferent activity to the heart and decreased sympathetic outflow to
arterioles
Correct Answer: C. Increased sympathetic outflow to the heart and increased
sympathetic vasoconstriction in most vascular beds
Rationale: Hemorrhage reduces MAP, unloading baroreceptors, which triggers increased
sympathetic outflow and decreased vagal tone. This increases heart rate, contractility, and
systemic vasoconstriction, rapidly raising MAP. Option C correctly describes this
integrated response.
Page 3
, Why Wrong:
A - Decreased sympathetic outflow and increased vagal tone would lower heart rate
and contractility, worsening hypotension.
B - While vasoconstriction in skin and kidneys is part of the response, decreased
sympathetic outflow to skeletal muscle would dilate those beds, reducing total
peripheral resistance and counteracting the needed increase.
D - Increased vagal activity decreases heart rate, and decreased sympathetic outflow to
arterioles causes vasodilation, both of which would further decrease MAP.
Reference: Guyton, A.C. & Hall, J.E. (2026). Textbook of Medical Physiology, 14th ed.,
Ch. 18.
Q3. In an individual with chronic hypoxemia due to high altitude, what molecular
adaptation leads to increased erythropoietin (EPO) production, and how does this
alter the oxygen-hemoglobin dissociation curve?
A. Stabilization of hypoxia-inducible factor (HIF-1) leading to increased EPO
transcription; curve shifts right
B. Increased renal blood flow and oxygen delivery inhibiting HIF-1 degradation; curve
shifts left
C. Upregulation of prolyl hydroxylase reducing HIF-1 levels; curve shifts right
D. Direct activation of the EPO gene by low P50; curve shifts left
Correct Answer: A. Stabilization of hypoxia-inducible factor (HIF-1) leading to
increased EPO transcription; curve shifts right
Rationale: Hypoxemia stabilizes HIF-1± by inhibiting its prolyl hydroxylase-mediated
degradation. HIF-1 accumulates, translocates to the nucleus, and binds to
hypoxia-response elements to drive EPO transcription. Increased EPO boosts red cell
mass, and the associated increase in 2,3-BPG shifts the oxygen-hemoglobin dissociation
curve to the right, enhancing oxygen unloading in tissues.
Why Wrong:
B - Increased renal blood flow would deliver more oxygen, not reduce it, and would
actually inhibit HIF-1, decreasing EPO; a left shift would impair oxygen unloading.
C - Upregulation of prolyl hydroxylase would promote HIF-1 degradation, reducing
EPO; a right shift is correct but the mechanism is opposite.
D - The EPO gene is not directly sensitive to P50; P50 is a measure of hemoglobin
affinity, not a molecular signal. Low P50 indicates higher affinity, shifting curve left,
not right.
Reference: Boron, W.F. & Boulpaep, E.L. (2025). Medical Physiology, 3rd ed., Ch. 27 &
49.
Q4. Which change in Starling forces across a systemic capillary would MOST directly
reduce net filtration and promote fluid reabsorption into the capillary?
Page 4
