BIO105 | BIO105 Anatomy and Physiology 1 Exam
4 Version 2 | Questions with Correct Answers and
Expert Explanation for Each Question | Saint Paul’s
School of Nursing
1. Which layer of the heart wall is primarily composed of cardiac muscle tissue and is
responsible for the heart’s pumping action?
A. Endocardium
B. Epicardium
C. Myocardium
D. Pericardium
Correct Answer: C
Expert Explanation: The myocardium is the thick middle layer of the heart wall
consisting of cardiac muscle. It performs the essential function of contracting to
pump blood throughout the circulatory system. The thickness of this layer varies
between chambers, being thickest in the left ventricle to handle high pressure.
Damage to this layer, such as in a myocardial infarction, severely impairs cardiac
function. Proper assessment of myocardial health is a core component of
cardiovascular monitoring.
,2. Which valve prevents the backflow of blood from the right ventricle into the right
atrium during ventricular contraction?
A. Aortic valve
B. Mitral valve
C. Tricuspid valve
D. Pulmonary valve
Correct Answer: C
Expert Explanation: The tricuspid valve is situated between the right atrium and
right ventricle. It closes during ventricular systole to ensure blood moves forward
into the pulmonary trunk. This prevention of backflow is crucial for maintaining
efficient pulmonary circulation and preventing venous congestion. Heart murmurs
heard in this area may indicate tricuspid regurgitation or stenosis. Clinical
monitoring of valve function is essential for diagnosing right-sided heart failure.
3. Which structure is known as the primary pacemaker of the heart, initiating the
electrical impulses for contraction?
A. AV node
B. SA node
C. Purkinje fibers
,D. Bundle of His
Correct Answer: B
Expert Explanation: The sinoatrial (SA) node is located in the wall of the right
atrium. It spontaneously generates electrical impulses that set the rhythm for the
entire heart. These signals spread across the atria, causing them to contract and
push blood into the ventricles. If the SA node fails, secondary pacemakers like the
AV node may take over at a slower rate. Monitoring the heart rate and rhythm via
EKG helps assess the functional integrity of the SA node.
4. During which phase of the cardiac cycle do the ventricles contract, forcing blood
into the aorta and pulmonary trunk?
A. Atrial diastole
B. Ventricular systole
C. Ventricular diastole
D. Atrial systole
Correct Answer: B
Expert Explanation: Ventricular systole is the phase of the cardiac cycle where the
ventricles undergo contraction. During this time, the pressure within the ventricles
rises above the pressure in the great arteries. This pressure gradient forces the
semilunar valves to open and blood to be ejected. Simultaneously, the
, atrioventricular valves close to prevent backflow into the atria. Efficient ventricular
systole is necessary to maintain adequate cardiac output and systemic perfusion.
5. What is the correct sequence of blood flow through the heart, starting from the
venae cavae?
A. Right atrium, tricuspid valve, right ventricle, pulmonary valve
B. Right ventricle, mitral valve, left atrium, aortic valve
C. Left atrium, tricuspid valve, left ventricle, pulmonary valve
D. Right atrium, mitral valve, right ventricle, aortic valve
Correct Answer: A
Expert Explanation: Deoxygenated blood returns from the body through the
superior and inferior venae cavae into the right atrium. From there, it passes
through the tricuspid valve into the right ventricle. The right ventricle then pumps
the blood through the pulmonary valve into the pulmonary arteries. This pathway
ensures that deoxygenated blood is sent to the lungs for gas exchange.
Understanding this sequence is fundamental for interpreting various cardiovascular
disorders and surgical interventions.
6. Which of the following factors would lead to an increase in cardiac output?
A. Increased parasympathetic stimulation
B. Decreased venous return
4 Version 2 | Questions with Correct Answers and
Expert Explanation for Each Question | Saint Paul’s
School of Nursing
1. Which layer of the heart wall is primarily composed of cardiac muscle tissue and is
responsible for the heart’s pumping action?
A. Endocardium
B. Epicardium
C. Myocardium
D. Pericardium
Correct Answer: C
Expert Explanation: The myocardium is the thick middle layer of the heart wall
consisting of cardiac muscle. It performs the essential function of contracting to
pump blood throughout the circulatory system. The thickness of this layer varies
between chambers, being thickest in the left ventricle to handle high pressure.
Damage to this layer, such as in a myocardial infarction, severely impairs cardiac
function. Proper assessment of myocardial health is a core component of
cardiovascular monitoring.
,2. Which valve prevents the backflow of blood from the right ventricle into the right
atrium during ventricular contraction?
A. Aortic valve
B. Mitral valve
C. Tricuspid valve
D. Pulmonary valve
Correct Answer: C
Expert Explanation: The tricuspid valve is situated between the right atrium and
right ventricle. It closes during ventricular systole to ensure blood moves forward
into the pulmonary trunk. This prevention of backflow is crucial for maintaining
efficient pulmonary circulation and preventing venous congestion. Heart murmurs
heard in this area may indicate tricuspid regurgitation or stenosis. Clinical
monitoring of valve function is essential for diagnosing right-sided heart failure.
3. Which structure is known as the primary pacemaker of the heart, initiating the
electrical impulses for contraction?
A. AV node
B. SA node
C. Purkinje fibers
,D. Bundle of His
Correct Answer: B
Expert Explanation: The sinoatrial (SA) node is located in the wall of the right
atrium. It spontaneously generates electrical impulses that set the rhythm for the
entire heart. These signals spread across the atria, causing them to contract and
push blood into the ventricles. If the SA node fails, secondary pacemakers like the
AV node may take over at a slower rate. Monitoring the heart rate and rhythm via
EKG helps assess the functional integrity of the SA node.
4. During which phase of the cardiac cycle do the ventricles contract, forcing blood
into the aorta and pulmonary trunk?
A. Atrial diastole
B. Ventricular systole
C. Ventricular diastole
D. Atrial systole
Correct Answer: B
Expert Explanation: Ventricular systole is the phase of the cardiac cycle where the
ventricles undergo contraction. During this time, the pressure within the ventricles
rises above the pressure in the great arteries. This pressure gradient forces the
semilunar valves to open and blood to be ejected. Simultaneously, the
, atrioventricular valves close to prevent backflow into the atria. Efficient ventricular
systole is necessary to maintain adequate cardiac output and systemic perfusion.
5. What is the correct sequence of blood flow through the heart, starting from the
venae cavae?
A. Right atrium, tricuspid valve, right ventricle, pulmonary valve
B. Right ventricle, mitral valve, left atrium, aortic valve
C. Left atrium, tricuspid valve, left ventricle, pulmonary valve
D. Right atrium, mitral valve, right ventricle, aortic valve
Correct Answer: A
Expert Explanation: Deoxygenated blood returns from the body through the
superior and inferior venae cavae into the right atrium. From there, it passes
through the tricuspid valve into the right ventricle. The right ventricle then pumps
the blood through the pulmonary valve into the pulmonary arteries. This pathway
ensures that deoxygenated blood is sent to the lungs for gas exchange.
Understanding this sequence is fundamental for interpreting various cardiovascular
disorders and surgical interventions.
6. Which of the following factors would lead to an increase in cardiac output?
A. Increased parasympathetic stimulation
B. Decreased venous return
