NU 631 EXAMINATION QUESTIONS AND VERIFIED
ANSWERS
Which cardiac chamber has the thickest wall?
Left atrium
Right atrium
Left ventricle
Right ventricle - The atria are approximately 1 to 2 mm thick. The right ventricle is 4 to 5 mm
thick, and the left ventricle, the most muscular chamber, is approximately 12 to 15 mm thick.
Which statement accurately describes blood flow through the heart?
Blood flows from the left atrium through the tricuspid valve to the left ventricle.
Blood flows from the right atrium through the aortic valve to the right ventricle.
Blood flows from the right ventricle through the pulmonic semilunar valve.
Blood flows from the left ventricle through the bicuspid valve. - Blood flows from the right atrium
through the tricuspid valve to the right ventricle. Blood then travels from the right ventricle through the
pulmonic semilunar valve to the pulmonary circulation. Once in the pulmonary circulation, it is
oxygenated and travels to the left atrium through the bicuspid valve to the left ventricle. Blood leaves
the left ventricle through the aortic valve and enters the systemic circulation.
Heart - blood circulation - RT atrium - Tricuspid - RT Ventricle - Pulmonic Semilunar valve -
Pulmonary circulation
L atrium - Bicuspid valve - L ventricle - aortic valve - systemic circulation
Which artery travels in the coronary sulcus between the left atrium and the left ventricle?
Left anterior descending
Circumflex
Right coronary
Left coronar - The circumflex artery travels in the coronary sulcus.
,The left anterior descending artery travels down the anterior surface of the interventricular septum. The
right coronary artery originates from an ostium behind the right aortic cusp and travels behind the
pulmonary artery. The left coronary artery passes between the left atrial appendage and the pulmonary
artery and generally divides into two branches.
Which part of the heart is responsible for electrical impulse stimulation?
Atrioventricular node Incorrect
Sinus node Correct
Bundle of His
Right bundle branch - The sinus node, the pacemaker of the heart, is the site of impulse
formation.
The atrioventricular node is the junction of the electrical transmission between the atria and the
ventricles. The impulse then travels to the bundle of His and, finally, to the right and left bundle
branches. The terminal branches are the Purkinje fibers.
Which cardiac event represents the measure of time from the onset of atrial activation to the onset of
ventricular activation?
PR interval
QRS complex
ST interval
QT interval - The PR interval measures the time of onset of atrial activation to the onset of
ventricular activation.
The QRS complex represents the sum of all ventricular muscle cell depolarization.
The ST interval is the time when the entire ventricular myocardium is depolarized.
The QT interval is often called electrical systole.
Which two items are related in the Frank-Starling law of the heart?
Resting sarcomere length to tension generation
Resting sarcomere length to end-diastolic volume
, Tension generation and left ventricular pressure Incorrect
Tension generation and diastolic filling pressures - The Frank-Starling law of the heart relates
resting sarcomere length (expressed as the volume of blood in the heart at the end of diastole or end-
diastolic volume) to tension generation (development of left ventricular pressure).
In summary, this means the volume of blood in the heart at the end of diastole is directly related to the
force of contraction of the next systole.
Which statement correctly defines preload?
Resistance to the ejection of blood from the left ventricle
Wall tension that is related to internal blood vessel radius
Lower tension curve than normal—a major characteristic
Pressure generated by the end-diastolic volume - Preload is the pressure generated in the left
ventricle at the end of diastole (end-diastolic volume).
Afterload is the resistance or impedance to the ejection of blood from the left ventricle.
Wall tension is directly related to the product of the intraventricular pressure and internal radius, and
inversely related to the wall thickness (Laplace's law). A tension curve lower than normal is characteristic
of congestive heart failure.
Which process is responsible for slowing the heart rate?
Sympathetic excitation
Parasympathetic excitation Correct
Bainbridge reflex
Baroreceptor reflex - The parasympathetic excitation slows the heart rate and is often referred to
as the cardioinhibitory center.
The sympathetic stimulation is often called the cardioexcitation center because the heart rate increases.
The Bainbridge reflex causes the heart rate to increase after intravenous infusions of blood or fluid. The
baroreceptor reflex facilitates blood pressure changes and heart rate changes.
Which factors determine cardiac output?
Parasympathetic and sympathetic activity
ANSWERS
Which cardiac chamber has the thickest wall?
Left atrium
Right atrium
Left ventricle
Right ventricle - The atria are approximately 1 to 2 mm thick. The right ventricle is 4 to 5 mm
thick, and the left ventricle, the most muscular chamber, is approximately 12 to 15 mm thick.
Which statement accurately describes blood flow through the heart?
Blood flows from the left atrium through the tricuspid valve to the left ventricle.
Blood flows from the right atrium through the aortic valve to the right ventricle.
Blood flows from the right ventricle through the pulmonic semilunar valve.
Blood flows from the left ventricle through the bicuspid valve. - Blood flows from the right atrium
through the tricuspid valve to the right ventricle. Blood then travels from the right ventricle through the
pulmonic semilunar valve to the pulmonary circulation. Once in the pulmonary circulation, it is
oxygenated and travels to the left atrium through the bicuspid valve to the left ventricle. Blood leaves
the left ventricle through the aortic valve and enters the systemic circulation.
Heart - blood circulation - RT atrium - Tricuspid - RT Ventricle - Pulmonic Semilunar valve -
Pulmonary circulation
L atrium - Bicuspid valve - L ventricle - aortic valve - systemic circulation
Which artery travels in the coronary sulcus between the left atrium and the left ventricle?
Left anterior descending
Circumflex
Right coronary
Left coronar - The circumflex artery travels in the coronary sulcus.
,The left anterior descending artery travels down the anterior surface of the interventricular septum. The
right coronary artery originates from an ostium behind the right aortic cusp and travels behind the
pulmonary artery. The left coronary artery passes between the left atrial appendage and the pulmonary
artery and generally divides into two branches.
Which part of the heart is responsible for electrical impulse stimulation?
Atrioventricular node Incorrect
Sinus node Correct
Bundle of His
Right bundle branch - The sinus node, the pacemaker of the heart, is the site of impulse
formation.
The atrioventricular node is the junction of the electrical transmission between the atria and the
ventricles. The impulse then travels to the bundle of His and, finally, to the right and left bundle
branches. The terminal branches are the Purkinje fibers.
Which cardiac event represents the measure of time from the onset of atrial activation to the onset of
ventricular activation?
PR interval
QRS complex
ST interval
QT interval - The PR interval measures the time of onset of atrial activation to the onset of
ventricular activation.
The QRS complex represents the sum of all ventricular muscle cell depolarization.
The ST interval is the time when the entire ventricular myocardium is depolarized.
The QT interval is often called electrical systole.
Which two items are related in the Frank-Starling law of the heart?
Resting sarcomere length to tension generation
Resting sarcomere length to end-diastolic volume
, Tension generation and left ventricular pressure Incorrect
Tension generation and diastolic filling pressures - The Frank-Starling law of the heart relates
resting sarcomere length (expressed as the volume of blood in the heart at the end of diastole or end-
diastolic volume) to tension generation (development of left ventricular pressure).
In summary, this means the volume of blood in the heart at the end of diastole is directly related to the
force of contraction of the next systole.
Which statement correctly defines preload?
Resistance to the ejection of blood from the left ventricle
Wall tension that is related to internal blood vessel radius
Lower tension curve than normal—a major characteristic
Pressure generated by the end-diastolic volume - Preload is the pressure generated in the left
ventricle at the end of diastole (end-diastolic volume).
Afterload is the resistance or impedance to the ejection of blood from the left ventricle.
Wall tension is directly related to the product of the intraventricular pressure and internal radius, and
inversely related to the wall thickness (Laplace's law). A tension curve lower than normal is characteristic
of congestive heart failure.
Which process is responsible for slowing the heart rate?
Sympathetic excitation
Parasympathetic excitation Correct
Bainbridge reflex
Baroreceptor reflex - The parasympathetic excitation slows the heart rate and is often referred to
as the cardioinhibitory center.
The sympathetic stimulation is often called the cardioexcitation center because the heart rate increases.
The Bainbridge reflex causes the heart rate to increase after intravenous infusions of blood or fluid. The
baroreceptor reflex facilitates blood pressure changes and heart rate changes.
Which factors determine cardiac output?
Parasympathetic and sympathetic activity
