BIOL 252 HUMAN ANATOMY & PHYSIOLOGY II W/LABMODULE 3 EXAM – EXAM-STYLE QUESTIONS AND
ANSWERS | VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED PASS | 2026/27
LATEST UPDATE | EXAM PREP | STUDY GUIDE | PRACTICE TEST
1. A patient presents with bradycardia, hypotension, and constricted pupils following an accidental
exposure to a cholinesterase inhibitor. Which of the following physiological effects is most directly
responsible for the observed bradycardia?
A. Enhanced sympathetic output to the sinoatrial node
B. Direct agonism at beta-1 adrenergic receptors
C. Prolonged action of acetylcholine at muscarinic receptors
D. Inhibition of parasympathetic activity at the cardiac plexus
Correct Answer: C. Prolonged action of acetylcholine at muscarinic receptors
*Rationale: * Cholinesterase inhibitors prevent the breakdown of acetylcholine (ACh), leading to its
accumulation at synapses. At the heart, ACh binds to muscarinic receptors on the sinoatrial node, which slows
the rate of depolarization, resulting in bradycardia. Option A is incorrect because sympathetic output would
increase heart rate. Option B is incorrect as the drug does not directly stimulate beta-1 receptors. Option D is
incorrect because parasympathetic activity is enhanced, not inhibited.
,2. During a routine echocardiogram, a technician notes a significant backflow of blood from the left
ventricle into the left atrium during systole. Which of the following valvular structures is most likely
incompetent?
A. Aortic semilunar valve
B. Pulmonary semilunar valve
C. Tricuspid valve
D. Mitral valve
Correct Answer: D. Mitral valve
*Rationale: * The mitral (bicuspid) valve is located between the left atrium and left ventricle. Its primary
function is to prevent backflow of blood into the left atrium during ventricular systole. Incompetence of this
valve would permit regurgitation. Options A and B are incorrect as they are semilunar valves located at the
exits of the ventricles. Option C, the tricuspid valve, is on the right side of the heart.
3. In a healthy individual at rest, which of the following represents the correct sequence of structures that
a red blood cell would pass through as it travels from the superior vena cava to the pulmonary trunk?
,A. Right atrium → tricuspid valve → right ventricle → pulmonary valve
B. Right atrium → mitral valve → right ventricle → pulmonary valve
C. Right ventricle → pulmonary valve → right atrium → tricuspid valve
D. Right atrium → pulmonary valve → right ventricle → tricuspid valve
Correct Answer: A. Right atrium → tricuspid valve → right ventricle → pulmonary valve
*Rationale: * Deoxygenated blood from the superior vena cava enters the right atrium, passes through the
tricuspid valve into the right ventricle, and then is ejected through the pulmonary valve into the pulmonary
trunk. Option B incorrectly uses the mitral valve. Option C and D reverse the correct anatomical and functional
order of flow.
4. A researcher is investigating factors that influence cardiac output. If stroke volume remains constant
and heart rate increases from 60 bpm to 120 bpm, what is the expected change in cardiac output?
A. It decreases by 50%
B. It remains unchanged
C. It doubles
D. It quadruples
Correct Answer: C. It doubles
, *Rationale: * Cardiac output (CO) is calculated by multiplying heart rate (HR) by stroke volume (SV) (CO = HR
× SV). If SV is constant and HR doubles, the resultant CO will also double. Option A is the inverse outcome.
Option B would only occur if the HR remained constant. Option D would require both HR and SV to double.
5. The administration of a drug that blocks the reuptake of norepinephrine at sympathetic nerve endings
would most likely result in which of the following hemodynamic changes?
A. Vasodilation and a decrease in blood pressure
B. Bronchoconstriction and decreased heart rate
C. Vasoconstriction and an increase in blood pressure
D. A decrease in myocardial contractility
Correct Answer: C. Vasoconstriction and an increase in blood pressure
*Rationale: * Blocking norepinephrine reuptake increases its concentration in the synaptic cleft, prolonging its
action on adrenergic receptors. Norepinephrine causes vasoconstriction and stimulates the heart, leading to
increased blood pressure. Option A is incorrect, as this would be an effect of decreased sympathetic activity.
Option B describes parasympathetic or bronchoconstrictive effects. Option D is incorrect because
norepinephrine increases myocardial contractility.
ANSWERS | VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED PASS | 2026/27
LATEST UPDATE | EXAM PREP | STUDY GUIDE | PRACTICE TEST
1. A patient presents with bradycardia, hypotension, and constricted pupils following an accidental
exposure to a cholinesterase inhibitor. Which of the following physiological effects is most directly
responsible for the observed bradycardia?
A. Enhanced sympathetic output to the sinoatrial node
B. Direct agonism at beta-1 adrenergic receptors
C. Prolonged action of acetylcholine at muscarinic receptors
D. Inhibition of parasympathetic activity at the cardiac plexus
Correct Answer: C. Prolonged action of acetylcholine at muscarinic receptors
*Rationale: * Cholinesterase inhibitors prevent the breakdown of acetylcholine (ACh), leading to its
accumulation at synapses. At the heart, ACh binds to muscarinic receptors on the sinoatrial node, which slows
the rate of depolarization, resulting in bradycardia. Option A is incorrect because sympathetic output would
increase heart rate. Option B is incorrect as the drug does not directly stimulate beta-1 receptors. Option D is
incorrect because parasympathetic activity is enhanced, not inhibited.
,2. During a routine echocardiogram, a technician notes a significant backflow of blood from the left
ventricle into the left atrium during systole. Which of the following valvular structures is most likely
incompetent?
A. Aortic semilunar valve
B. Pulmonary semilunar valve
C. Tricuspid valve
D. Mitral valve
Correct Answer: D. Mitral valve
*Rationale: * The mitral (bicuspid) valve is located between the left atrium and left ventricle. Its primary
function is to prevent backflow of blood into the left atrium during ventricular systole. Incompetence of this
valve would permit regurgitation. Options A and B are incorrect as they are semilunar valves located at the
exits of the ventricles. Option C, the tricuspid valve, is on the right side of the heart.
3. In a healthy individual at rest, which of the following represents the correct sequence of structures that
a red blood cell would pass through as it travels from the superior vena cava to the pulmonary trunk?
,A. Right atrium → tricuspid valve → right ventricle → pulmonary valve
B. Right atrium → mitral valve → right ventricle → pulmonary valve
C. Right ventricle → pulmonary valve → right atrium → tricuspid valve
D. Right atrium → pulmonary valve → right ventricle → tricuspid valve
Correct Answer: A. Right atrium → tricuspid valve → right ventricle → pulmonary valve
*Rationale: * Deoxygenated blood from the superior vena cava enters the right atrium, passes through the
tricuspid valve into the right ventricle, and then is ejected through the pulmonary valve into the pulmonary
trunk. Option B incorrectly uses the mitral valve. Option C and D reverse the correct anatomical and functional
order of flow.
4. A researcher is investigating factors that influence cardiac output. If stroke volume remains constant
and heart rate increases from 60 bpm to 120 bpm, what is the expected change in cardiac output?
A. It decreases by 50%
B. It remains unchanged
C. It doubles
D. It quadruples
Correct Answer: C. It doubles
, *Rationale: * Cardiac output (CO) is calculated by multiplying heart rate (HR) by stroke volume (SV) (CO = HR
× SV). If SV is constant and HR doubles, the resultant CO will also double. Option A is the inverse outcome.
Option B would only occur if the HR remained constant. Option D would require both HR and SV to double.
5. The administration of a drug that blocks the reuptake of norepinephrine at sympathetic nerve endings
would most likely result in which of the following hemodynamic changes?
A. Vasodilation and a decrease in blood pressure
B. Bronchoconstriction and decreased heart rate
C. Vasoconstriction and an increase in blood pressure
D. A decrease in myocardial contractility
Correct Answer: C. Vasoconstriction and an increase in blood pressure
*Rationale: * Blocking norepinephrine reuptake increases its concentration in the synaptic cleft, prolonging its
action on adrenergic receptors. Norepinephrine causes vasoconstriction and stimulates the heart, leading to
increased blood pressure. Option A is incorrect, as this would be an effect of decreased sympathetic activity.
Option B describes parasympathetic or bronchoconstrictive effects. Option D is incorrect because
norepinephrine increases myocardial contractility.
