BIOL 252 Human Anatomy & Physiology II w/Lab | Module 4 -
100 Questions and Answers Already Graded A+ Premium Exam
Tested And Verified
Subject Area Human Anatomy & Physiology II with Lab
Description Module 4 exam covering advanced topics in cardiovascular, respiratory, digestive,
renal, endocrine, lymphatic, and reproductive physiology. Emphasizes integrative
organ system function, homeostatic regulation, and clinical correlations at a
rigorous, research-intensive university level.
Expected Grade A+
Total Questions 100
Duration 3 hours
Learning Outcomes 1. Analyze the molecular mechanisms of cardiac action potential propagation and
excitation-contraction coupling.
2. Integrate pulmonary ventilation-perfusion matching and acid-base balance
regulation.
3. Evaluate renal handling of solutes and water under hormonal control.
4. Synthesize endocrine feedback loops and their disruption in pathophysiological
states.
Accreditation This exam meets the standards of the American Association of Anatomists and the
Human Anatomy and Physiology Society (HAPS) for rigorous undergraduate
education at R1 research universities.
Page 1
,1. In a ventricular cardiomyocyte, which of the following best explains the plateau
phase of the action potential?
A. Rapid inactivation of Na+ channels and activation of L-type Ca2+ channels, with delayed
rectifier K+ channels opening slowly.
B. Persistent activation of Na+ channels and inactivation of K+ channels, causing prolonged
depolarization.
C. Opening of T-type Ca2+ channels and closure of inward rectifier K+ channels,
maintaining depolarization.
D. Activation of Na+/Ca2+ exchanger in reverse mode, pumping Ca2+ in and Na+ out.
Answer: A. Rapid inactivation of Na+ channels and activation of L-type Ca2+
channels, with delayed rectifier K+ channels opening slowly.
The plateau phase in ventricular myocytes is due to the sustained influx of Ca2+
through L-type calcium channels while delayed rectifier potassium channels open
slowly, balancing repolarization. Option B is incorrect because Na+ channels inactivate
rapidly. Option C is wrong as T-type Ca2+ channels are not prominent in ventricular
cells. Option D describes a secondary mechanism, not the primary plateau.
2. A researcher measures the partial pressures of O2 and CO2 in systemic arterial
blood of a healthy individual at rest. Which of the following values is most consistent
with normal gas exchange?
A. PaO2 = 95 mm Hg, PaCO2 = 40 mm Hg, PvO2 = 40 mm Hg, PvCO2 = 45 mm Hg
B. PaO2 = 60 mm Hg, PaCO2 = 50 mm Hg, PvO2 = 30 mm Hg, PvCO2 = 55 mm Hg
C. PaO2 = 100 mm Hg, PaCO2 = 30 mm Hg, PvO2 = 50 mm Hg, PvCO2 = 35 mm Hg
D. PaO2 = 80 mm Hg, PaCO2 = 35 mm Hg, PvO2 = 45 mm Hg, PvCO2 = 40 mm Hg
Answer: A. PaO2 = 95 mm Hg, PaCO2 = 40 mm Hg, PvO2 = 40 mm Hg, PvCO2 =
45 mm Hg
Normal arterial PaO2 is 80-100 mm Hg and PaCO2 is 35-45 mm Hg; venous values are
lower O2 and higher CO2 due to tissue exchange. Option A matches these norms.
Option B indicates hypoxemia and hypercapnia. Option C has low PaCO2 (respiratory
alkalosis) and high venous O2 (possible shunt). Option D has slightly low PaO2 and
borderline CO2.
Page 2
,3. Which of the following best describes the role of the Na+/H+ exchanger (NHE3) in
the proximal tubule?
A. It mediates the majority of Na+ reabsorption and is coupled to H+ secretion, contributing
to HCO3- reclamation.
B. It reabsorbs Na+ in exchange for K+, regulating potassium balance.
C. It is the primary mechanism for Ca2+ reabsorption in the proximal tubule.
D. It functions in the thick ascending limb to generate the medullary osmotic gradient.
Answer: A. It mediates the majority of Na+ reabsorption and is coupled to H+
secretion, contributing to HCO3- reclamation.
NHE3 in the proximal tubule reabsorbs Na+ and secretes H+; the H+ combines with
filtered HCO3- to form H2CO3, which is broken down to CO2 and H2O, allowing
HCO3- reabsorption. Option B is incorrect because Na+/K+ exchange is not a primary
function in proximal tubule. Option C is wrong; Ca2+ reabsorption is mostly
paracellular. Option D describes NKCC2 in the thick ascending limb.
4. A patient with a suspected endocrine disorder undergoes a dexamethasone
suppression test. After administration of dexamethasone, plasma cortisol levels
remain elevated. Which of the following is the most likely diagnosis?
A. Cushing's disease (pituitary adenoma secreting ACTH)
B. Adrenal adenoma secreting cortisol autonomously
C. Ectopic ACTH syndrome from a small cell lung carcinoma
D. Cushing's syndrome due to exogenous glucocorticoid use
Answer: B. Adrenal adenoma secreting cortisol autonomously
Dexamethasone suppresses ACTH in normal and pituitary-dependent Cushing's disease
(high-dose test), but not in adrenal adenomas because cortisol secretion is
ACTH-independent. Option A would show suppression with high-dose dexamethasone.
Option C may show partial suppression but often not. Option D would suppress
endogenous ACTH and cortisol, but exogenous glucocorticoids cause low cortisol.
Page 3
, 5. In the context of the renin-angiotensin-aldosterone system (RAAS), which of the
following correctly describes the effect of angiotensin II on the kidney?
A. It constricts afferent arterioles more than efferent arterioles, increasing GFR.
B. It constricts efferent arterioles more than afferent arterioles, preserving GFR in low
perfusion states.
C. It directly inhibits Na+ reabsorption in the proximal tubule.
D. It stimulates the release of atrial natriuretic peptide (ANP) from the heart.
Answer: B. It constricts efferent arterioles more than afferent arterioles,
preserving GFR in low perfusion states.
Angiotensin II preferentially constricts efferent arterioles, increasing filtration fraction
and maintaining GFR when renal perfusion pressure drops. Option A is incorrect
because constriction of afferent arterioles would reduce GFR. Option C is wrong;
angiotensin II stimulates Na+ reabsorption. Option D is incorrect; ANP is released in
response to atrial stretch, not angiotensin II.
6. A laboratory simulation demonstrates that increasing the frequency of action
potentials in a presynaptic neuron leads to summation of EPSPs in the postsynaptic
neuron. Which of the following mechanisms best explains this phenomenon?
A. Temporal summation due to rapid succession of stimuli before repolarization completes.
B. Spatial summation from multiple presynaptic inputs converging on the same postsynaptic
neuron.
C. Facilitation caused by residual Ca2+ in the presynaptic terminal enhancing
neurotransmitter release.
D. Post-tetanic potentiation from a prolonged increase in presynaptic Ca2+ levels.
Answer: A. Temporal summation due to rapid succession of stimuli before
repolarization completes.
Temporal summation occurs when a single presynaptic neuron fires rapidly, producing
EPSPs that add together before the membrane potential returns to baseline. Option B
describes spatial summation, which involves multiple inputs. Option C is facilitation,
which enhances release but is not summation per se. Option D is a longer-lasting form
of facilitation.
Page 4
100 Questions and Answers Already Graded A+ Premium Exam
Tested And Verified
Subject Area Human Anatomy & Physiology II with Lab
Description Module 4 exam covering advanced topics in cardiovascular, respiratory, digestive,
renal, endocrine, lymphatic, and reproductive physiology. Emphasizes integrative
organ system function, homeostatic regulation, and clinical correlations at a
rigorous, research-intensive university level.
Expected Grade A+
Total Questions 100
Duration 3 hours
Learning Outcomes 1. Analyze the molecular mechanisms of cardiac action potential propagation and
excitation-contraction coupling.
2. Integrate pulmonary ventilation-perfusion matching and acid-base balance
regulation.
3. Evaluate renal handling of solutes and water under hormonal control.
4. Synthesize endocrine feedback loops and their disruption in pathophysiological
states.
Accreditation This exam meets the standards of the American Association of Anatomists and the
Human Anatomy and Physiology Society (HAPS) for rigorous undergraduate
education at R1 research universities.
Page 1
,1. In a ventricular cardiomyocyte, which of the following best explains the plateau
phase of the action potential?
A. Rapid inactivation of Na+ channels and activation of L-type Ca2+ channels, with delayed
rectifier K+ channels opening slowly.
B. Persistent activation of Na+ channels and inactivation of K+ channels, causing prolonged
depolarization.
C. Opening of T-type Ca2+ channels and closure of inward rectifier K+ channels,
maintaining depolarization.
D. Activation of Na+/Ca2+ exchanger in reverse mode, pumping Ca2+ in and Na+ out.
Answer: A. Rapid inactivation of Na+ channels and activation of L-type Ca2+
channels, with delayed rectifier K+ channels opening slowly.
The plateau phase in ventricular myocytes is due to the sustained influx of Ca2+
through L-type calcium channels while delayed rectifier potassium channels open
slowly, balancing repolarization. Option B is incorrect because Na+ channels inactivate
rapidly. Option C is wrong as T-type Ca2+ channels are not prominent in ventricular
cells. Option D describes a secondary mechanism, not the primary plateau.
2. A researcher measures the partial pressures of O2 and CO2 in systemic arterial
blood of a healthy individual at rest. Which of the following values is most consistent
with normal gas exchange?
A. PaO2 = 95 mm Hg, PaCO2 = 40 mm Hg, PvO2 = 40 mm Hg, PvCO2 = 45 mm Hg
B. PaO2 = 60 mm Hg, PaCO2 = 50 mm Hg, PvO2 = 30 mm Hg, PvCO2 = 55 mm Hg
C. PaO2 = 100 mm Hg, PaCO2 = 30 mm Hg, PvO2 = 50 mm Hg, PvCO2 = 35 mm Hg
D. PaO2 = 80 mm Hg, PaCO2 = 35 mm Hg, PvO2 = 45 mm Hg, PvCO2 = 40 mm Hg
Answer: A. PaO2 = 95 mm Hg, PaCO2 = 40 mm Hg, PvO2 = 40 mm Hg, PvCO2 =
45 mm Hg
Normal arterial PaO2 is 80-100 mm Hg and PaCO2 is 35-45 mm Hg; venous values are
lower O2 and higher CO2 due to tissue exchange. Option A matches these norms.
Option B indicates hypoxemia and hypercapnia. Option C has low PaCO2 (respiratory
alkalosis) and high venous O2 (possible shunt). Option D has slightly low PaO2 and
borderline CO2.
Page 2
,3. Which of the following best describes the role of the Na+/H+ exchanger (NHE3) in
the proximal tubule?
A. It mediates the majority of Na+ reabsorption and is coupled to H+ secretion, contributing
to HCO3- reclamation.
B. It reabsorbs Na+ in exchange for K+, regulating potassium balance.
C. It is the primary mechanism for Ca2+ reabsorption in the proximal tubule.
D. It functions in the thick ascending limb to generate the medullary osmotic gradient.
Answer: A. It mediates the majority of Na+ reabsorption and is coupled to H+
secretion, contributing to HCO3- reclamation.
NHE3 in the proximal tubule reabsorbs Na+ and secretes H+; the H+ combines with
filtered HCO3- to form H2CO3, which is broken down to CO2 and H2O, allowing
HCO3- reabsorption. Option B is incorrect because Na+/K+ exchange is not a primary
function in proximal tubule. Option C is wrong; Ca2+ reabsorption is mostly
paracellular. Option D describes NKCC2 in the thick ascending limb.
4. A patient with a suspected endocrine disorder undergoes a dexamethasone
suppression test. After administration of dexamethasone, plasma cortisol levels
remain elevated. Which of the following is the most likely diagnosis?
A. Cushing's disease (pituitary adenoma secreting ACTH)
B. Adrenal adenoma secreting cortisol autonomously
C. Ectopic ACTH syndrome from a small cell lung carcinoma
D. Cushing's syndrome due to exogenous glucocorticoid use
Answer: B. Adrenal adenoma secreting cortisol autonomously
Dexamethasone suppresses ACTH in normal and pituitary-dependent Cushing's disease
(high-dose test), but not in adrenal adenomas because cortisol secretion is
ACTH-independent. Option A would show suppression with high-dose dexamethasone.
Option C may show partial suppression but often not. Option D would suppress
endogenous ACTH and cortisol, but exogenous glucocorticoids cause low cortisol.
Page 3
, 5. In the context of the renin-angiotensin-aldosterone system (RAAS), which of the
following correctly describes the effect of angiotensin II on the kidney?
A. It constricts afferent arterioles more than efferent arterioles, increasing GFR.
B. It constricts efferent arterioles more than afferent arterioles, preserving GFR in low
perfusion states.
C. It directly inhibits Na+ reabsorption in the proximal tubule.
D. It stimulates the release of atrial natriuretic peptide (ANP) from the heart.
Answer: B. It constricts efferent arterioles more than afferent arterioles,
preserving GFR in low perfusion states.
Angiotensin II preferentially constricts efferent arterioles, increasing filtration fraction
and maintaining GFR when renal perfusion pressure drops. Option A is incorrect
because constriction of afferent arterioles would reduce GFR. Option C is wrong;
angiotensin II stimulates Na+ reabsorption. Option D is incorrect; ANP is released in
response to atrial stretch, not angiotensin II.
6. A laboratory simulation demonstrates that increasing the frequency of action
potentials in a presynaptic neuron leads to summation of EPSPs in the postsynaptic
neuron. Which of the following mechanisms best explains this phenomenon?
A. Temporal summation due to rapid succession of stimuli before repolarization completes.
B. Spatial summation from multiple presynaptic inputs converging on the same postsynaptic
neuron.
C. Facilitation caused by residual Ca2+ in the presynaptic terminal enhancing
neurotransmitter release.
D. Post-tetanic potentiation from a prolonged increase in presynaptic Ca2+ levels.
Answer: A. Temporal summation due to rapid succession of stimuli before
repolarization completes.
Temporal summation occurs when a single presynaptic neuron fires rapidly, producing
EPSPs that add together before the membrane potential returns to baseline. Option B
describes spatial summation, which involves multiple inputs. Option C is facilitation,
which enhances release but is not summation per se. Option D is a longer-lasting form
of facilitation.
Page 4
