BIO 336 Exam 2 Principles of Human Physiology
Questions with Answers| San Diego State University| Pass
Guaranteed
1. Which structures deliver deoxygenated blood to the right atrium?
A. The pulmonary veins
B. The superior vena cava, inferior vena cava, and coronary sinus
C. The pulmonary arteries and aorta
D. The aorta and coronary arteries
Answer: B
Rationale: Systemic venous blood returns to the right atrium via the superior and
inferior venae cavae, while the coronary sinus drains the myocardium's own
venous blood. The pulmonary veins carry oxygenated blood to the left atrium.
2. Which valve lies between the left atrium and left ventricle?
A. The tricuspid valve
B. The aortic valve
C. The pulmonic valve
D. The mitral (bicuspid) valve
Answer: D
Rationale: The mitral valve is the left atrioventricular (AV) valve with two cusps.
The tricuspid valve is the right AV valve, and the aortic and pulmonic valves are
semilunar valves at the ventricular outlets.
3. Which is the correct sequence of blood flow through the heart beginning at
the right atrium?
A. Right atrium, tricuspid valve, right ventricle, pulmonic valve, pulmonary
artery, lungs, pulmonary veins, left atrium, mitral valve, left ventricle, aortic
valve, aorta
B. Right atrium, mitral valve, right ventricle, aortic valve, pulmonary artery,
lungs, pulmonary veins, left atrium
C. Right atrium, tricuspid valve, right ventricle, aortic valve, aorta, lungs, left
atrium, mitral valve
, D. Left atrium, tricuspid valve, right ventricle, pulmonic valve, lungs, right
atrium, mitral valve, left ventricle
Answer: A
Rationale: Blood flows right atrium to right ventricle through the tricuspid valve,
then out the pulmonic valve to the lungs. It returns via the pulmonary veins to the
left atrium, crosses the mitral valve to the left ventricle, and exits through the
aortic valve.
4. What is the function of the chordae tendineae and papillary muscles?
A. They open the semilunar valves during systole
B. They conduct action potentials from the AV node to the ventricles
C. They anchor the AV valve cusps and prevent them from prolapsing back into
the atria during ventricular contraction
D. They generate the pressure that closes the aortic valve
Answer: C
Rationale: Papillary muscles contract with the ventricle and tension the chordae
tendineae, which tether the AV valve leaflets. This keeps the leaflets closed
against high ventricular pressure. Valves themselves move passively with pressure
gradients.
5. Why is the wall of the left ventricle much thicker than that of the right
ventricle?
A. The left ventricle pumps a larger stroke volume than the right ventricle
B. The left ventricle must generate high pressure to pump blood through the
high-resistance systemic circulation
C. The right ventricle has no cardiac muscle
D. The left ventricle contains more valves
Answer: B
Rationale: Both ventricles eject the same stroke volume, but the systemic circuit
has much higher resistance than the pulmonary circuit. The left ventricle therefore
generates roughly 120 mmHg versus about 25 mmHg for the right, and its greater
workload results in a thicker wall.
6. Approximately what are the peak systolic pressures in the right ventricle and
the left ventricle in a healthy adult?
, A. Right ventricle about 120 mmHg; left ventricle about 25 mmHg
B. Both ventricles about 120 mmHg
C. Right ventricle about 80 mmHg; left ventricle about 10 mmHg
D. Right ventricle about 25 mmHg; left ventricle about 120 mmHg
Answer: D
Rationale: The pulmonary circulation is a low-pressure, low-resistance circuit, so
right ventricular systolic pressure is around 25 mmHg. The left ventricle must drive
blood into the aorta, generating about 120 mmHg.
7. How do the AV valves and semilunar valves open and close?
A. Passively, in response to pressure gradients across the valve
B. Actively, by contraction of smooth muscle within the cusps
C. By direct nervous stimulation from the vagus nerve
D. By calcium release from the sarcoplasmic reticulum in the cusps
Answer: A
Rationale: Heart valves contain no muscle. A valve opens when upstream pressure
exceeds downstream pressure and closes when the gradient reverses, which
prevents backflow.
8. When does most coronary blood flow to the left ventricular myocardium
occur, and why?
A. During systole, because aortic pressure is highest
B. Equally in systole and diastole, since the coronary arteries are rigid
C. During diastole, because contraction of the ventricle in systole compresses
the intramyocardial vessels
D. Only during atrial contraction
Answer: C
Rationale: During ventricular systole, wall tension squeezes the coronary vessels
running through the myocardium and limits flow. In diastole the muscle relaxes
and aortic pressure drives perfusion, so a shortened diastole (as in tachycardia)
can compromise coronary flow.
9. What is the role of intercalated discs in cardiac muscle?
A. They store calcium for contraction
, B. Desmosomes hold cells together mechanically, and gap junctions allow
action potentials to spread rapidly from cell to cell so the muscle acts as a
functional syncytium
C. They release acetylcholine onto cardiac cells
D. They insulate the atria from the ventricles
Answer: B
Rationale: Intercalated discs join adjacent cardiac myocytes. Gap junctions
provide low-resistance electrical coupling, and desmosomes resist the mechanical
stress of repeated contraction.
10. Which structure electrically separates the atria from the ventricles, so that
the AV node is normally the only conduction pathway between them?
A. The interventricular septum
B. The pericardium
C. The chordae tendineae
D. The fibrous skeleton of the heart
Answer: D
Rationale: The fibrous connective tissue skeleton surrounds the valve rings and
does not conduct action potentials. It forces the impulse to pass through the AV
node, producing the delay that allows ventricular filling, and it anchors the valves.
11. Which vessel carries oxygenated blood?
A. The pulmonary vein
B. The pulmonary artery
C. The superior vena cava
D. The coronary sinus
Answer: A
Rationale: Vessels are named by direction relative to the heart, not oxygen
content. Pulmonary arteries carry deoxygenated blood to the lungs, while
pulmonary veins return oxygenated blood to the left atrium.
12. Where is the sinoatrial (SA) node located?
A. In the interventricular septum
B. In the wall of the left ventricle
Questions with Answers| San Diego State University| Pass
Guaranteed
1. Which structures deliver deoxygenated blood to the right atrium?
A. The pulmonary veins
B. The superior vena cava, inferior vena cava, and coronary sinus
C. The pulmonary arteries and aorta
D. The aorta and coronary arteries
Answer: B
Rationale: Systemic venous blood returns to the right atrium via the superior and
inferior venae cavae, while the coronary sinus drains the myocardium's own
venous blood. The pulmonary veins carry oxygenated blood to the left atrium.
2. Which valve lies between the left atrium and left ventricle?
A. The tricuspid valve
B. The aortic valve
C. The pulmonic valve
D. The mitral (bicuspid) valve
Answer: D
Rationale: The mitral valve is the left atrioventricular (AV) valve with two cusps.
The tricuspid valve is the right AV valve, and the aortic and pulmonic valves are
semilunar valves at the ventricular outlets.
3. Which is the correct sequence of blood flow through the heart beginning at
the right atrium?
A. Right atrium, tricuspid valve, right ventricle, pulmonic valve, pulmonary
artery, lungs, pulmonary veins, left atrium, mitral valve, left ventricle, aortic
valve, aorta
B. Right atrium, mitral valve, right ventricle, aortic valve, pulmonary artery,
lungs, pulmonary veins, left atrium
C. Right atrium, tricuspid valve, right ventricle, aortic valve, aorta, lungs, left
atrium, mitral valve
, D. Left atrium, tricuspid valve, right ventricle, pulmonic valve, lungs, right
atrium, mitral valve, left ventricle
Answer: A
Rationale: Blood flows right atrium to right ventricle through the tricuspid valve,
then out the pulmonic valve to the lungs. It returns via the pulmonary veins to the
left atrium, crosses the mitral valve to the left ventricle, and exits through the
aortic valve.
4. What is the function of the chordae tendineae and papillary muscles?
A. They open the semilunar valves during systole
B. They conduct action potentials from the AV node to the ventricles
C. They anchor the AV valve cusps and prevent them from prolapsing back into
the atria during ventricular contraction
D. They generate the pressure that closes the aortic valve
Answer: C
Rationale: Papillary muscles contract with the ventricle and tension the chordae
tendineae, which tether the AV valve leaflets. This keeps the leaflets closed
against high ventricular pressure. Valves themselves move passively with pressure
gradients.
5. Why is the wall of the left ventricle much thicker than that of the right
ventricle?
A. The left ventricle pumps a larger stroke volume than the right ventricle
B. The left ventricle must generate high pressure to pump blood through the
high-resistance systemic circulation
C. The right ventricle has no cardiac muscle
D. The left ventricle contains more valves
Answer: B
Rationale: Both ventricles eject the same stroke volume, but the systemic circuit
has much higher resistance than the pulmonary circuit. The left ventricle therefore
generates roughly 120 mmHg versus about 25 mmHg for the right, and its greater
workload results in a thicker wall.
6. Approximately what are the peak systolic pressures in the right ventricle and
the left ventricle in a healthy adult?
, A. Right ventricle about 120 mmHg; left ventricle about 25 mmHg
B. Both ventricles about 120 mmHg
C. Right ventricle about 80 mmHg; left ventricle about 10 mmHg
D. Right ventricle about 25 mmHg; left ventricle about 120 mmHg
Answer: D
Rationale: The pulmonary circulation is a low-pressure, low-resistance circuit, so
right ventricular systolic pressure is around 25 mmHg. The left ventricle must drive
blood into the aorta, generating about 120 mmHg.
7. How do the AV valves and semilunar valves open and close?
A. Passively, in response to pressure gradients across the valve
B. Actively, by contraction of smooth muscle within the cusps
C. By direct nervous stimulation from the vagus nerve
D. By calcium release from the sarcoplasmic reticulum in the cusps
Answer: A
Rationale: Heart valves contain no muscle. A valve opens when upstream pressure
exceeds downstream pressure and closes when the gradient reverses, which
prevents backflow.
8. When does most coronary blood flow to the left ventricular myocardium
occur, and why?
A. During systole, because aortic pressure is highest
B. Equally in systole and diastole, since the coronary arteries are rigid
C. During diastole, because contraction of the ventricle in systole compresses
the intramyocardial vessels
D. Only during atrial contraction
Answer: C
Rationale: During ventricular systole, wall tension squeezes the coronary vessels
running through the myocardium and limits flow. In diastole the muscle relaxes
and aortic pressure drives perfusion, so a shortened diastole (as in tachycardia)
can compromise coronary flow.
9. What is the role of intercalated discs in cardiac muscle?
A. They store calcium for contraction
, B. Desmosomes hold cells together mechanically, and gap junctions allow
action potentials to spread rapidly from cell to cell so the muscle acts as a
functional syncytium
C. They release acetylcholine onto cardiac cells
D. They insulate the atria from the ventricles
Answer: B
Rationale: Intercalated discs join adjacent cardiac myocytes. Gap junctions
provide low-resistance electrical coupling, and desmosomes resist the mechanical
stress of repeated contraction.
10. Which structure electrically separates the atria from the ventricles, so that
the AV node is normally the only conduction pathway between them?
A. The interventricular septum
B. The pericardium
C. The chordae tendineae
D. The fibrous skeleton of the heart
Answer: D
Rationale: The fibrous connective tissue skeleton surrounds the valve rings and
does not conduct action potentials. It forces the impulse to pass through the AV
node, producing the delay that allows ventricular filling, and it anchors the valves.
11. Which vessel carries oxygenated blood?
A. The pulmonary vein
B. The pulmonary artery
C. The superior vena cava
D. The coronary sinus
Answer: A
Rationale: Vessels are named by direction relative to the heart, not oxygen
content. Pulmonary arteries carry deoxygenated blood to the lungs, while
pulmonary veins return oxygenated blood to the left atrium.
12. Where is the sinoatrial (SA) node located?
A. In the interventricular septum
B. In the wall of the left ventricle
