Chapter 32
1. Which cardiac chamber has the thickest wall?
- Left ventricle
The atria are approximately 1–2 mm thick. The right ventricle is 4–5 mm thick, and the left
ventricle, the most muscular chamber, is approximately 12–15 mm thick.
2. Which statement accurately describes blood flow through the heart?
- Blood flows from the right ventricle through the pulmonic semilunar 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.
3. Which statement correctly describes the A wave?
- The A wave is generated by atrial contraction.
The A wave is generated by atrial contraction. The V wave is the early diastolic peak caused by
the filling of the atrium. The X descent follows the A wave and is produced because of the
descent of the tricuspid valve ring. The Y descent follows the V wave and reflects the rapid flow
of blood from the great veins and right atrium into the right ventricle.
4. Which artery travels in the coronary sulcus between the left atrium and the
left ventricle?
- Circumflex
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.
5. Which part of the heart is responsible for electrical impulse stimulation?
- Sinus node
,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.
6. Which cardiac event represents the measure of time from the onset of atrial
activation to the onset of ventricular activation?
- PR 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.
7. Which two items are related in the Frank-Starling law of the heart?
- Resting sarcomere length to tension generation
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.
8. Which statement correctly defines preload?
- 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.
9. Which process is responsible for slowing the heart rate?
- Parasympathetic excitation
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.
, 10. Which factors determine cardiac output?
- Heart rate and stroke volume
Cardiac output is directly related to the heart rate and stroke volume. Changes in either
variable affect the cardiac output. 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. Although the parasympathetic stimulation has a bradycardic
effect and sympathetic nervous system increases the frequency of the cardiac pacemaker and
may influence cardiac output, these factors are not used in the cardiac output formula; neither
are atrial pressures.
11. Which statement is true regarding the thoracic duct?
- The thoracic duct receives lymph from most of the body.
Lymph is primarily water and small amounts of protein. It is reabsorbed through the lymph
nodes and delivered to either the right lymphatic duct (lymph from right arm, head, and
thorax) or the thoracic duct (rest of the body). These structures, in turn, dump the lymph into
the inferior vena cava and superior vena cava (major sources of venous return to the heart),
which conduct blood to the right atrium.
12. Which are the functions of the pericardial sac?
- Prevents displacement of the heart during gravitational acceleration or deceleration
- Physical barrier that protects the heart against infection and inflammation
- Contains pain receptors and mechanoreceptors that affect blood pressure
Functions of the pericardial sac are: (1) to prevent the displacement of the heart during
gravitational acceleration or deceleration, (2) to provide a physical barrier that protects the
heart against infection and inflammation from the lungs and pleural space, and (3) to provide
pain receptors and mechanoreceptors that can elicit reflex changes in blood pressure and
heart rate. The endocardium is the lining that is continuous with the arteries, veins, and
capillaries of the body and creates a continuous closed circulatory system.
Chapter 33
1. Which term describes an occlusion in a blood vessel caused by a bolus of
circulating matter in the bloodstream?
- Embolus
1. Which cardiac chamber has the thickest wall?
- Left ventricle
The atria are approximately 1–2 mm thick. The right ventricle is 4–5 mm thick, and the left
ventricle, the most muscular chamber, is approximately 12–15 mm thick.
2. Which statement accurately describes blood flow through the heart?
- Blood flows from the right ventricle through the pulmonic semilunar 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.
3. Which statement correctly describes the A wave?
- The A wave is generated by atrial contraction.
The A wave is generated by atrial contraction. The V wave is the early diastolic peak caused by
the filling of the atrium. The X descent follows the A wave and is produced because of the
descent of the tricuspid valve ring. The Y descent follows the V wave and reflects the rapid flow
of blood from the great veins and right atrium into the right ventricle.
4. Which artery travels in the coronary sulcus between the left atrium and the
left ventricle?
- Circumflex
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.
5. Which part of the heart is responsible for electrical impulse stimulation?
- Sinus node
,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.
6. Which cardiac event represents the measure of time from the onset of atrial
activation to the onset of ventricular activation?
- PR 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.
7. Which two items are related in the Frank-Starling law of the heart?
- Resting sarcomere length to tension generation
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.
8. Which statement correctly defines preload?
- 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.
9. Which process is responsible for slowing the heart rate?
- Parasympathetic excitation
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.
, 10. Which factors determine cardiac output?
- Heart rate and stroke volume
Cardiac output is directly related to the heart rate and stroke volume. Changes in either
variable affect the cardiac output. 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. Although the parasympathetic stimulation has a bradycardic
effect and sympathetic nervous system increases the frequency of the cardiac pacemaker and
may influence cardiac output, these factors are not used in the cardiac output formula; neither
are atrial pressures.
11. Which statement is true regarding the thoracic duct?
- The thoracic duct receives lymph from most of the body.
Lymph is primarily water and small amounts of protein. It is reabsorbed through the lymph
nodes and delivered to either the right lymphatic duct (lymph from right arm, head, and
thorax) or the thoracic duct (rest of the body). These structures, in turn, dump the lymph into
the inferior vena cava and superior vena cava (major sources of venous return to the heart),
which conduct blood to the right atrium.
12. Which are the functions of the pericardial sac?
- Prevents displacement of the heart during gravitational acceleration or deceleration
- Physical barrier that protects the heart against infection and inflammation
- Contains pain receptors and mechanoreceptors that affect blood pressure
Functions of the pericardial sac are: (1) to prevent the displacement of the heart during
gravitational acceleration or deceleration, (2) to provide a physical barrier that protects the
heart against infection and inflammation from the lungs and pleural space, and (3) to provide
pain receptors and mechanoreceptors that can elicit reflex changes in blood pressure and
heart rate. The endocardium is the lining that is continuous with the arteries, veins, and
capillaries of the body and creates a continuous closed circulatory system.
Chapter 33
1. Which term describes an occlusion in a blood vessel caused by a bolus of
circulating matter in the bloodstream?
- Embolus
