Chapter 20 The Heart
Which of these would cause stroke volume to increase? A) when diastolic blood pressure is decreased B) when venous return is decreased C) when ventricular contraction is reduced D) decrease in heart rate E) All of the answers are correct.
A) when diastolic blood pressure is decreased
At a heart rate of 60 beats/minute, a cardiac cycle lasts A) 1 second. B) 60 milliseconds. C) 370 milliseconds. D) 630 milliseconds. E) 60 seconds.
A) 1 second.
The heart beats approximately ________ times each day. A) 100,000 B) 1,000,000 C) 10,000,000 D) 10,000 E) 1,000
A) 100,000
The systolic part (both atrial and ventricular) of a cardiac cycle lasts on average A) 370 msec. B) 5 seconds. C) 800 msec. D) 3 seconds. E) 100 msec.
A) 370 msec.
35) There are ________ pulmonary veins. A) 4 B) 12 C) 2 D) 8 E) 6
A) 4
Heart rate is controlled by neurons of the cardiovascular center located in the A) medulla oblongata. B) thalamus. C) pons. D) hypothalamus. E) higher centers.
A) medulla oblongata.
In order to perform a CABG, a cardiac surgeon must A) open the pericardial sac. B) visualize the carotid arteries. C) open the myocardium to see the AV valves. D) visualize the pulmonary valve. E) All of the answers are correct.
A) open the pericardial sac.
Excess fluid in the ________ causes cardiac tamponade. A) pericardial cavity B) apex of heart C) visceral pericardium D) both atria E) left ventricle
A) pericardial cavity
Contractions of the papillary muscles A) prevent the atrioventricular valves from reversing into the atria. B) close the semilunar valves. C) eject blood from the ventricles. D) eject blood from the atria into the ventricles. E) close the atrioventricular valves.
A) prevent the atrioventricular valves from reversing into the atria.
The volume of blood ejected from each ventricle during a contraction is called the A) end-diastolic volume. B) stroke volume. C) end-systolic volume. D) cardiac output. E) cardiac reserve.
B) stroke volume.
Cardiac output is increased by A) decreased venous return. B) sympathetic stimulation. C) increased end systolic volume. D) inhibiting the atrial reflex. E) decreased end diastolic volume.
B) sympathetic stimulation.
Blood is supplied to the myocardium by A) the coronary sinus. B) the coronary arteries. C) arteries that branch off the subclavian arteries. D) contact with blood in the pumping chambers. E) arteries that branch from the pulmonary arteries.
B) the coronary arteries.
The foramen ovale in the fetal heart is located in the A) left atrium. B) left ventricle. C) right ventricle. D) interatrial septum. E) right atrium.
D) interatrial septum.
The first heart sound ("lub") A) is associated with opening of the aortic valve. B) is associated with closing of the aortic valve. C) is associated with opening of the mitral valve. D) is associated with closing of the mitral valve. E) is associated with atrial systole.
D) is associated with closing of the mitral valve.
Blood returning to the heart from the pulmonary circuit first enters the A) conus arteriosus. B) right ventricle. C) right atrium. D) left atrium. E) left ventricle.
D) left atrium.
The circumflex branch and the anterior interventricular artery are branches of the A) coronary sinus. B) aorta. C) interventricular artery. D) left coronary artery. E) right coronary artery.
D) left coronary artery.
The right pulmonary veins carry ________ blood to the ________ . A) oxygenated; right lung B) deoxygenated; superior vena cava C) deoxygenated; left atrium D) oxygenated; left atrium E) deoxygenated; right atrium
D) oxygenated; left atrium
The right ventricle pumps blood to the A) right atrium. B) left atrium. C) aorta. D) right and left lungs. E) left ventricle.
D) right and left lungs.
Blood returning to the heart from the systemic circuit first enters the A) conus arteriosus. B) left ventricle. C) right ventricle. D) right atrium. E) left atrium.
D) right atrium.
Which of the following are involved in the pulmonary circuit? A) left ventricle, pulmonary veins, right atrium B) right ventricle, pulmonary veins, aorta C) superior vena cava, right atrium, left ventricle D) right ventricle, pulmonary trunk, left atrium E) inferior vena cava, right atrium, aorta
D) right ventricle, pulmonary trunk, left atrium
The pulmonary semilunar valve prevents backward flow into the A) aorta. B) pulmonary trunk. C) left atrium. D) right ventricle. E) pulmonary veins.
D) right ventricle.
The right atrium receives blood from the A) superior vena cava. B) inferior vena cava. C) coronary sinus. D) systemic circuit. E) All of the answers are correct.
D) systemic circuit.
The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the A) atrial systole. B) dicrotic phase. C) late diastolic filling phase. D) systolic ejection phase. E) early diastolic filling phase.
D) systolic ejection phase.
As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit A) treppe. B) fatigue. C) tonus. D) tetany. E) recruitment.
D) tetany.
The normal pacemaker of the heart is located in A) the atrioventricular node. B) both the left and right ventricles. C) the wall of the left ventricle. D) the sinoatrial node. E) the Purkinje fibers.
D) the sinoatrial node.
Blood flowing into the heart from the venae cavae flows next through the ________ valve. A) pulmonary semilunar B) bicuspid C) mitral D) tricuspid E) aortic semilunar
D) tricuspid
Put in correct order the sequence in which excitation would move through the conducting system of the heart: 1. Purkinje fibers 4. SA node 2. AV bundle 5. bundle branches 3. AV node A) 1, 4, 3, 2, 5. B) 3, 5, 4, 2, 1. C) 3, 2, 4, 5, 1. D) 4, 2, 3, 5, 1. E) 4, 3, 2, 5, 1.
E) 4, 3, 2, 5, 1.
A heart murmur might be caused by A) swirling of blood in the ventricle. B) aortic valve insufficiency. C) mitral valve insufficiency. D) pulmonic valve insufficiency. E) All of the answers are correct.
E) All of the answers are correct.
Cardiac cells damaged by infarction will show which of the following? A) release of enzymes into the circulation B) switch to anaerobic metabolism C) release of CK-MB into the circulation D) release of troponin T and I into the circulation E) All of the answers are correct.
E) All of the answers are correct.
Drugs known as calcium channel blockers such as nifedipine can be used to A) dilate the coronary arteries. B) produce a negative inotropic effect. C) decrease the force of cardiac contraction. D) decrease blood pressure. E) All of the answers are correct.
E) All of the answers are correct.
Intercalated discs serve to transfer ________ from cell to cell. A) the force of contraction B) action potentials C) electrical signals D) ionic currents E) All of the answers are correct.
E) All of the answers are correct.
Rupture of the papillary muscles in the left ventricle may result in A) bicuspid regurgitation. B) mitral regurgitation. C) bicuspid prolapse. D) mitral valve prolapse. E) All of the answers are correct.
E) All of the answers are correct.
Stroke volume depends on A) the contractility of the ventricle. B) end diastolic volume. C) venous return of blood to the heart. D) the pressure required to pump blood into the aorta. E) All of the answers are correct.
E) All of the answers are correct.
The connective tissue fibers of the myocardium A) provide physical support for cardiac muscle. B) provide elasticity to help return the heart to its normal size. C) add strength and prevent overexpansion of the heart. D) help distribute the forces of contraction. E) All of the answers are correct.
E) All of the answers are correct.
The interventricular sulci and coronary sulcus A) contain arteries. B) are grooves on the surface of the heart. C) contain veins. D) contain fat. E) All of the answers are correct.
E) All of the answers are correct.
Which of the following would increase heart rate? A) faster depolarization of the pacemaker potential B) increased levels of epinephrine C) increased sympathetic stimulation of SA node D) decreased parasympathetic stimulation of nodal fibers E) All of the answers are correct.
E) All of the answers are correct.
Which of these is true about the atrial reflex? A) also called Bainbridge reflex B) triggered by atrial mechanoreceptors C) depends on sympathetic innervation D) triggered by increasing venous return E) All of the answers are correct.
E) All of the answers are correct.
________ is to slow heart rate as ________ is to fast heart rate. A) Angina; infarction B) Bradycardia; cardiomyopathy C) Cardiac tamponade; bradycardia D) Tachycardia; bradycardia E) Bradycardia; tachycardia
E) Bradycardia; tachycardia
Depolarization of the atria corresponds to the EKG's A) S-T segment. B) QT interval. C) T wave. D) QRS complex. E) P wave.
E) P wave.
Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing. A) P-R interval B) R-T interval C) T wave D) P wave E) QRS complex
E) QRS complex
The heart is innervated by ________ nerves. A) somatomotor B) neither parasympathetic nor sympathetic C) sympathetic D) parasympathetic E) both parasympathetic and sympathetic
E) both parasympathetic and sympathetic
During the T wave of the electrocardiogram, the ventricles are A) repolarizing. B) depolarizing. C) relaxing. D) contracting. E) both repolarizing and relaxing.
E) both repolarizing and relaxing
The term used to describe fluid collecting in the pericardial cavity that restricts the movement of the heart is known as A) cardiomyopathy. B) mitral valve prolapse. C) pericarditis. D) pleural effusion. E) cardiac tamponade.
E) cardiac tamponade.
As blood leaves the right ventricle it passes through the ________ and then into the pulmonary trunk. A) aorta B) superior vena cava C) pulmonary veins D) inferior vena cava E) conus arteriosus
E) conus arteriosus
The first blood vessels to branch from the aorta are the ________ arteries. A) subclavian B) circumflex C) pulmonary D) carotid E) coronary
E) coronary
Artery is to ________ as vein is to ________. A) efferent; away B) afferent; away C) afferent; efferent D) toward; away E) efferent; afferent
E) efferent; afferent
If the pacemaker cells in the SA node become more permeable to potassium ions, the A) cells will hyperpolarize. B) cells will depolarize. C) heart rate will increase. D) heart rate will decrease. E) heart rate will decrease and cells will hyperpolarize.
E) heart rate will decrease and cells will hyperpolarize.
48) The following is a list of vessels and structures that are associated with the heart. 1. right atrium 2. left atrium 3. right ventricle 4. left ventricle 5. venae cavae 6. aorta 7. pulmonary trunk 8. pulmonary veins What is the correct order for the flow of blood entering from the systemic circulation? A) 5, 1, 3, 7, 8, 2, 4, 6 B) 1, 2, 7, 8, 3, 4, 6, 5 C) 5, 3, 1, 7, 8, 4, 2, 6 D) 5, 1, 3, 8, 7, 2, 4, 6 E) 1, 7, 3, 8, 2, 4, 6, 5
A) 5, 1, 3, 7, 8, 2, 4, 6
During ventricular systole, the A) AV valves are closed. B) pressure in the aorta remains constant. C) pressure in the ventricles remains constant. D) blood is entering the ventricles. E) atria are contracting.
A) AV valves are closed.
Depolarization of the ventricles is represented on an electrocardiogram by the A) QRS complex. B) T wave. C) PR complex. D) P wave. E) S wave.
A) QRS complex.
The adult heart is roughly the size of A) a man's clenched fist. B) the liver. C) the brain. D) the hand of a 10-year-old. E) the gallbladder.
A) a man's clenched fist.
The earlike extension of the atrium is the A) auricle. B) coronary sulcus. C) ventricle. D) atricle. E) coronary sinus.
A) auricle.
The bicuspid or mitral valve is located A) between the left atrium and left ventricle. B) in the opening of the aorta. C) in the opening of the pulmonary trunk. D) where the venae cavae join the right atrium. E) between the right atrium and right ventricle.
A) between the left atrium and left ventricle.
The ________ valve prevents backward flow into the left atrium. A) bicuspid B) semicaval C) pulmonic D) semilunar E) tricuspid
A) bicuspid
Most of the middle layer in the heart wall is composed of A) cardiac muscle cells. B) smooth muscle cells. C) fibrocytes. D) epitheliocytes. E) chondrocytes.
A) cardiac muscle cells.
The ________ deliver(s) blood to the myocardium. A) coronary arteries B) cardiac veins C) carotid arteries D) coronary sinus E) superior vena cava
A) coronary arteries
The great and middle cardiac veins drain blood into the A) coronary sinus. B) superior vena cava. C) inferior vena cava. D) aorta. E) coronary sulcus.
A) coronary sinus.
When a blood clot forms on a ruptured plaque in a coronary artery, the condition is referred to as a(n) A) coronary thrombosis. B) myocardial infarction. C) coronary spasm. D) angina pectoris. E) pulmonary embolism.
A) coronary thrombosis
When the left ventricle contracts, the diameter of the ventricular chamber A) decreases. B) remains the same. C) increases.
A) decreases.
When the left ventricle contracts, the distance from the apex to the base A) decreases. B) increases. C) remains unchanged.
A) decreases.
The P wave of the electrocardiogram is a signal from A) depolarization of the atria. B) depolarization of the SA node. C) depolarization of the ventricles. D) repolarization of the atria. E) depolarization of the AV node.
A) depolarization of the atria.
The visceral pericardium is the same as the A) epicardium. B) mediastinum. C) endocardium. D) myocardium. E) parietal pericardium.
A) epicardium.
Blood is supplied to the left atrium by the A) left coronary artery. B) pulmonary arteries. C) brachiocephalic artery. D) phrenic arteries. E) right coronary artery.
A) left coronary artery.
In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the A) mediastinum. B) pleural space. C) ventral cavity. D) pericardial space. E) cardiac notch.
A) mediastinum.
"An increase in end-diastolic volume increases the stroke volume" is a way of stating A) Robin's law of the heart. B) Starling's law of the heart. C) Sparrow's law of the heart. D) Finch's law of the heart. E) Hawking's law of the heart.
B) Starling's law of the heart.
Pacemaker cells in the SA node A) are special neurons that convey signals from the brain to the heart. B) can spontaneously depolarize. C) also contract with the rest of the cells in the heart wall. D) have a well-defined resting potential. E) All of the answers are correct.
B) can spontaneously depolarize.
The structure that permits blood flow from the right atrium to the left atrium in the fetal circulation is the A) fossa ovalis. B) foramen ovale. C) coronary sinus. D) interatrial septum. E) ligamentum arteriosus.
B) foramen ovale.
The atrioventricular valves permit blood flow A) in both directions. B) in one direction only. C) in many directions. D) from a ventricle to an atrium. E) in opposite directions on the right and left.
B) in one direction only.
The pulmonary arteries carry blood to the A) liver. B) lungs. C) heart. D) brain. E) intestines.
B) lungs.
The coronary sulcus is a groove that A) marks the boundary line between the right and left ventricles. B) marks the border between the atria and ventricles. C) separates the atrioventricular valves from the atria. D) separates the coronary arteries from the coronary veins. E) marks the boundary line between the right and left atria.
B) marks the border between the atria and ventricles.
Tetanic muscle contractions don't occur in a normal cardiac muscle because A) cardiac muscle tissue contracts on its own. B) the refractory period lasts until the muscle relaxes. C) neural stimulation is lacking. D) potassium channels outnumber sodium channels. E) the refractory period ends before the muscle reaches peak tension.
B) the refractory period lasts until the muscle relaxes.
The following are structural components of the conducting system of the heart. 1. Purkinje fibers 2. AV bundle 3. AV node 4. SA node 5. bundle branches The sequence in which excitation would move through this system is A) 3, 5, 4, 2, 1. B) 1, 4, 3, 2, 5. C) 4, 3, 2, 5, 1. D) 4, 2, 3, 5, 1. E) 3, 2, 4, 5, 1.
C) 4, 3, 2, 5, 1.
The first heart sound is heard when the A) semilunar valves close. B) AV valves open. C) AV valves close. D) atria contract. E) blood enters the aorta.
C) AV valves close.
The cardioacceleratory center activates sympathetic neurons and the cardioinhibitory center controls parasympathetic neurons. A) Both parts of the statement are false. B) Both parts of the statement are true. C) Both parts of the statement are true and relate to brainstem control of heart rate. D) The first part of the statement is false but the second part is true. E) The first part of the statement is true but the second part is false.
C) Both parts of the statement are true and relate to brainstem control of heart rate.
Cardiac muscle cells and skeletal muscle cells differ in a few ways. Which of the following is not one of them? A) Cardiac muscle cells have a single, centered nucleus. B) Cardiac muscle cells branch. C) Cardiac muscle cells lack transverse tubules. D) Skeletal muscle cells lack intercalated discs. E) Cardiac muscle cells are smaller in size.
C) Cardiac muscle cells lack transverse tubules
If there is a complete block between the SA node and the AV node, how would the ECG be affected? A) There will be much bigger P waves. B) The P-R interval will be shorter. C) The rate of P waves will be faster than the rate of QRS complexes. D) The QRS duration will be longer. E) The ventricles will stop beating.
C) The rate of P waves will be faster than the rate of QRS complexes.
In cardiac muscle A) calcium ions play no role in the process of contraction. B) calcium ions play an important role in repolarizing the membrane after the depolarization phase. C) about 20 percent of the calcium ion required for contraction comes from outside the cell. D) calcium ions are not released from the sarcoplasmic reticulum. E) calcium ions do not bind to troponin molecules.
C) about 20 percent of the calcium ion required for contraction comes from outside the cell.
With each ventricular systole, A) cardiac output decreases. B) the ventricles fill with blood. C) blood pressure increases. D) blood pressure remains steady. E) blood pressure decreases.
C) blood pressure increases.
The long plateau phase of the cardiac muscle action potential is due to A) increased membrane permeability to potassium ion. B) increased membrane permeability to sodium ions. C) calcium channels remaining open. D) movement of fewer sodium ions across the cell membrane. E) decrease in the amount of calcium diffusing across the membrane.
C) calcium channels remaining open.
The cusps (leaflets) of atrioventricular valves attach directly to A) trabeculae carneae. B) coronary sulci. C) chordae tendineae. D) papillary muscles. E) interatrial septa.
C) chordae tendineae.
The function of an atrium is to A) collect blood. B) pump blood to the lungs. C) collect blood then pump it to the ventricle. D) pump blood into the systemic circuit. E) pump blood to the ventricle.
C) collect blood then pump it to the ventricle.
Cardiac output can be increased by all of the following except one. Choose the exception. A) increasing heart rate B) decreasing end systolic volume C) decreasing ejection fraction D) increasing ejection fraction E) increasing stroke volume
C) decreasing ejection fraction
When the semilunar valves close, the AV valves then A) make the third heart sound. B) prolapse. C) open. D) close. E) contract.
C) open.
Analysis of the electrocardiogram can reveal all of the following, except the A) condition of the conducting system. B) heart rate. C) stroke volume. D) effects of drugs and poisons. E) duration of the ventricular action potential.
C) stroke volume.
If the connection between the SA node and AV node becomes blocked, A) the atria will contract more forcefully. B) the ventricles will beat faster. C) the ventricles will beat more slowly. D) the ventricular beat will remain unchanged. E) cardiac output will increase.
C) the ventricles will beat more slowly.
The T wave on an ECG tracing represents A) ventricular contraction. B) ventricular depolarization. C) ventricular repolarization. D) atrial depolarization. E) atrial repolarization.
C) ventricular repolarization.
The heart pumps approximately ________ liters of blood each day. A) 100,000 B) 15,000 C) 20,000 D) 8,000 E) 50,000
D) 8,000
Pacemaker cells isolated from the SA node generate action potentials at ________ beats per minute. A) 100-140 B) 40-60 C) 20-40 D) 80-100 E) 140-180
D) 80-100
Considering the left ventricle, why does isovolumetric ventricular contraction occur during ventricular systole? A) The ventricle is still filling with blood and therefore cannot eject blood during this time. B) The ventricle needs to pressurize the blood to close the aortic valve. C) The bicuspid valve needs time to shut before the ventricle can eject blood. D) Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve. E) Ventricular pressure is greater than atrial pressure so the ventricle cannot eject blood.
D) Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve.
The left ventricle pumps blood to the A) pulmonary circuit. B) right ventricle. C) lungs. D) aorta. E) right atrium.
D) aorta.
Which of the following descriptions matches the term near the left fifth intercostal space? A) visceral pericardium B) aorta C) pericardial cavity D) apex of heart E) right atrium
D) apex of heart
Activation of which kind of receptor causes heart rate to increase? A) muscarinic receptor B) alpha-one receptor C) preganglionic D) beta-one receptor E) beta-two receptor
D) beta-one receptor
An increase in the rate of action potentials from baroreceptors will trigger a reflex to A) decrease in blood pressure. B) increase in heart rate. C) decrease in heart rate. D) both decrease heart rate and decrease pressure. E) both increase heart rate and increase pressure.
D) both decrease heart rate and decrease pressure.
The pulmonary veins carry blood to the A) intestines. B) liver. C) brain. D) heart. E) lungs.
D) heart.
In cardiac muscle, the fast depolarization phase of the action potential is the result of A) decreased membrane permeability to calcium ions. B) increased membrane permeability to chloride ions. C) increased membrane permeability to potassium ions. D) decreased membrane permeability to sodium ions. E) increased membrane permeability to sodium ions.
E) increased membrane permeability to sodium ions.
Each of the following factors will increase cardiac output, except A) increased force of contraction. B) increased venous return. C) increased heart rate. D) increased sympathetic stimulation. E) increased parasympathetic stimulation.
E) increased parasympathetic stimulation.
Blood leaves the right ventricle by passing through the A) bicuspid valve. B) tricuspid valve. C) mitral valve. D) aortic valve. E) pulmonary valve.
E) pulmonary valve.
Compared to the right ventricle, the left ventricle has all the following characteristics, except that it A) works harder. B) produces about four to six times more pressure when it contracts. C) has a thicker wall. D) is round in cross section. E) pumps a greater volume.
E) pumps a greater volume.
Coronary veins empty into the A) left atrium. B) conus arteriosus. C) left ventricle. D) right ventricle. E) right atrium.
E) right atrium.
The marginal branch and posterior interventricular branch are branches of the A) aorta. B) coronary sinus. C) left coronary artery. D) circumflex artery. E) right coronary artery.
E) right coronary artery.