Chapter 18

7) An abnormally slow heart rate. A) Bradycardia B) Cardiac reserve C) Tachycardia D) Vagal tone

A) Bradycardia

18) An abnormal pacemaker. A) Ectopic focus B) Quiescent period C) Fibrillation D) Ischemia E) Infarction

A) Ectopic focus

1) The inner lining of the heart. A) Endocardium B) Parietal layer C) Myocardium D) Epicardium

A) Endocardium

37) Which of the events below does NOT occur when the semilunar valves are open? A) Ventricles are in diastole. B) Blood enters pulmonary arteries and the aorta. C) Ventricles are in systole. D) AV valves are closed.

A) Ventricles are in diastole.

47) Which of the following factors does NOT influence heart rate? A) gender B) body temperature C) age D) skin color

D) skin color

73) While auscultating heart sounds during a checkup, Andy's doctor hears a high-pitched sound during ventricular contraction. Which type of valve could cause this? A) incompetent tricuspid valve B) deficient pulmonary semilunar valve C) insufficient mitral (bicuspid) valve D) stenotic aortic semilunar valve

D) stenotic aortic semilunar valve

8) Difference between resting and maximal cardiac output. A) Bradycardia B) Cardiac reserve C) Tachycardia D) Vagal tone

B) Cardiac reserve

82) List and define the three most important factors that affect stroke volume.

1. Preload the degree to which heart muscle cells are stretched before they contract 2. Contractility contractile strength achieved at a given muscle length 3. Afterload pressure that must be overcome for the ventricles to eject blood

9) Prevents backflow into the left ventricle. A) Aortic semilunar valve B) Mitral (bicuspid) valve C) Tricuspid valve D) Pulmonary semilunar valve

A) Aortic semilunar valve

42) The condition where fluid compresses the heart and limits its ability to contract is called ________. A) cardiac tamponade B) myocardial infarction C) pericarditis D) angina pectoris

A) cardiac tamponade

51) Norepinephrine acts on the heart by ________. A) causing threshold to be reached more quickly B) blocking the action of calcium C) causing a decrease in stroke volume D) decreasing heart contractility

A) causing threshold to be reached more quickly

53) The foramen ovale ________. A) connected the two atria in the fetal heart B) is a condition in which the heart valves do not completely close C) is a connection between the pulmonary trunk and the aorta in the fetus D) is a shallow depression in the interventricular septum

A) connected the two atria in the fetal heart

45) The source of blood carried to capillaries in the myocardium would be the ________. A) coronary arteries B) coronary veins C) coronary sinus D) fossa ovalis

A) coronary arteries

49) If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________. A) decreased delivery of oxygen B) an inadequate supply of lactic acid C) a lack of nutrients to feed into metabolic pathways D) a decrease in the number of available mitochondria for energy production

A) decreased delivery of oxygen

41) Blood within the pulmonary veins returns to the ________. A) left atrium B) right atrium C) right ventricle D) left ventricle

A) left atrium

74) Exercise results in skeletal muscles compressing veins which encourages blood to return to the heart. In this scenario, which of the following is correct? A) preload increases B) venous return decreases C) stroke volume decreases D) end diastolic volume (EDV) decreases

A) preload increases

54) Which vessel(s) of the heart receive(s) blood from the right ventricle? A) pulmonary trunk B) aorta C) pulmonary veins D) venae cavae

A) pulmonary trunk

71) Which of the following transports oxygen-rich blood? A) pulmonary vein B) pulmonary artery C) pulmonary trunk D) superior vena cava

A) pulmonary vein

46) The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________. A) pumps blood against a greater resistance B) expands the thoracic cage C) sends blood through a smaller valve D) pumps a greater volume of blood

A) pumps blood against a greater resistance

67) Isovolumetric contraction ________. A) refers to the short period during ventricular systole when the ventricles are completely closed chambers B) occurs immediately after the aortic and pulmonary semilunar valves close C) occurs while the atrioventricular (AV) valves are open D) occurs only in people with heart valve defects

A) refers to the short period during ventricular systole when the ventricles are completely closed chambers

44) To auscultate the aortic semilunar valve, you would place your stethoscope in the ________. A) second intercostal space to the right of the sternum B) second intercostal space to the left of the sternum C) fifth right intercostal space D) fifth intercostal space inferior to the left nipple

A) second intercostal space to the right of the sternum

52) If the vagal nerves to the heart were cut, the result would be that ________. A) the heart rate would increase by about 25 beats per minute B) parasympathetic stimulation would increase, causing a decrease in heart rate C) the atrioventricular (AV) node would become the pacemaker of the heart D) the heart would stop, since the vagal nerves trigger the heart to contract

A) the heart rate would increase by about 25 beats per minute

85) A patient takes a nitroglycerin tablet sublingually for chest pain. Nitroglycerin acts directly on smooth muscle, producing relaxation and vessel dilation. How would this relieve chest pain?

Angina pectoris is thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium, with resulting decreased oxygen being delivered to the cells. Because nitroglycerin acts as a vasodilator (similar to nitric oxide), blood flow is increased, promoting the delivery of oxygen to the cells.

76) What is the difference between the auricles and the atria?

Auricles are the flaplike appendages attached to the atria that increase the atrial volume. The atria are receiving chambers for blood returning to the heart from the pulmonary and systemic circulation.

72) What is the expected heart rate when a heart is removed from a living body? A) 75 beats / minute B) 100 beats / minute C) 50 beats / minute D) the heart would immediately stop beating

B) 100 beats / minute

68) Given an end diastolic volume (EDV) of 120 ml / beat and an end systolic volume (ESV) of 50 ml / beat, the stroke volume (SV) would be ________. A) 170 ml / beat B) 70 ml / beat C) 120 ml / beat D) 50 ml / beat

B) 70 ml / beat

11) Prevents backflow into the left atrium. A) Aortic semilunar valve B) Mitral (bicuspid) valve C) Tricuspid valve D) Pulmonary semilunar valve

B) Mitral (bicuspid) valve

13) Atrioventricular (AV) valve with two flaps. A) Aortic semilunar valve B) Mitral (bicuspid) valve C) Tricuspid valve D) Pulmonary semilunar valve

B) Mitral (bicuspid) valve

4) The outermost layer of the serous pericardium. A) Endocardium B) Parietal layer C) Myocardium D) Epicardium

B) Parietal layer

19) Total heart relaxation. A) Ectopic focus B) Quiescent period C) Fibrillation D) Ischemia E) Infarction

B) Quiescent period

58) Select the correct statement about the heart valves. A) The mitral (bicuspid) valve separates the right atrium from the right ventricle. B) The atrioventricular (AV) valves prevent backflow of blood into the atria during ventricular contraction. C) Aortic and pulmonary semilunar valves control the flow of blood into the heart. D) The tricuspid valve divides the left atrium from the left ventricle.

B) The atrioventricular (AV) valves prevent backflow of blood into the atria during ventricular contraction.

43) The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________. A) pericarditis B) myocardial infarct C) angina pectoris D) ischemia

C) angina pectoris

60) Select the correct statement about the structure of the heart wall. A) Connective tissue in the heart wall aids in the conduction of the action potential. B) The myocardium is the layer of the heart that actually contracts. C) The fibrous cardiac skeleton forms the bulk of the heart. D) The heart chambers are lined by the endomysium.

B) The myocardium is the layer of the heart that actually contracts.

38) Hemorrhage with a large loss of blood causes ________. A) no change in blood pressure but a slower heart rate B) a lowering of blood pressure due to change in cardiac output C) no change in blood pressure but a change in respiration D) a rise in blood pressure due to change in cardiac output

B) a lowering of blood pressure due to change in cardiac output

40) The P wave of a normal electrocardiogram indicates ________. A) ventricular repolarization B) atrial depolarization C) atrial repolarization D) ventricular depolarization

B) atrial depolarization

39) Damage to the ________ causes heart block. A) sinoatrial (SA) node B) atrioventricular (AV) node C) atrioventricular (AV) bundle D) atrioventricular (AV) valves

B) atrioventricular (AV) node

62) During the period of ventricular filling ________. A) the aortic and pulmonary semilunar valves are open B) blood flows mostly passively through the atria and the open atrioventricular (AV) valves into the ventricles C) the atria remain in diastole D) pressure in the heart is at its peak

B) blood flows mostly passively through the atria and the open atrioventricular (AV) valves into the ventricles

36) Normal heart sounds are caused by which of the following events? A) friction of blood against the chamber walls B) closure of the heart valves C) opening of the heart valves D) excitation of the sinoatrial (SA) node

B) closure of the heart valves

63) The second heart sound is heard during which phase of the cardiac cycle? A) ventricular filling B) isovolumetric relaxation C) isovolumetric contraction D) ventricular ejection

B) isovolumetric relaxation

66) During contraction of heart muscle cells ________. A) all of the calcium required for contraction comes from storage in the sarcoplasmic reticulum B) some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores C) calcium is prevented from entering cardiac fibers that have been stimulated D) the action potential is prevented from spreading from cell to cell by gap junctions

B) some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores

50) If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells, ________. A) contractions would last as long as the refractory period B) tetanic contractions might occur, which would stop the heart's pumping action C) pacemaker cells would cease to spontaneously depolarize D) it would be much longer before cardiac cells could respond to a second stimulation

B) tetanic contractions might occur, which would stop the heart's pumping action

48) Which of the following is NOT an age-related change affecting the heart? A) decline in cardiac reserve B) thinning of the valve flaps C) atherosclerosis D) fibrosis of cardiac muscle

B) thinning of the valve flaps

64) If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________. A) tetanic contraction would occur due to the short absolute refractory period of cardiac muscle B) threshold is reached more quickly and heart rate would increase C) potassium channels compensate and no change in heart rate would occur D) heart rate would decrease, but blood pressure would rise due to the excess sodium present

B) threshold is reached more quickly and heart rate would increase

59) Select the correct statement about the function of myocardial cells. A) The refractory period in skeletal muscle is much longer than that in cardiac muscle. B) Cardiac muscle cells are innervated by sympathetic, parasympathetic, and somatic nerve fibers so that the nervous system can increase heart rate. C) The entire heart contracts as a unit or it does not contract at all. D) The influx of potassium ions from extracellular sources is the initiating event in cardiac muscle contraction.

C) The entire heart contracts as a unit or it does not contract at all.

10) Prevents backflow into the right atrium. A) Aortic semilunar valve B) Mitral (bicuspid) valve C) Tricuspid valve D) Pulmonary semilunar valve

C) Tricuspid valve

87) A 55-year-old male was admitted to the hospital with heart failure. He complains of increasing shortness of breath on exertion and needing to sleep on three pillows at night. On physical assessment, the nurse determines that his ankles and feet are very swollen. Which of these symptoms reflect left-sided heart failure and which reflect right-sided heart failure?

Because the heart is a double pump, each side can initially fail independently of the other. If the left side fails, pulmonary congestion occurs. The right side of the heart continues to propel blood to the lungs, but the left side does not adequately eject the returning blood into the systemic circulation. Thus, blood vessels in the lungs become engorged with blood, pressure within them increases, and fluid leaks from the circulation into the lung tissue, causing pulmonary edema. Shortness of breath and difficulty breathing in a prone position may occur. If the right side of the heart fails, peripheral congestion occurs. Blood stagnates within body organs, and pooled fluids in the tissue spaces impair the ability of body cells to obtain adequate nutrients and oxygen and to rid themselves of wastes. Edema is most noticeable in the extremities (feet, ankles, and fingers).

89) A patient is prescribed a calcium channel blocker to prevent angina (chest pain), by decreasing the demand for oxygen. Explain why.

By preventing the influx of calcium ions into myocardial and vascular smooth muscle cells, calcium channel blockers inhibit the intracellular release of additional stores of calcium ions. A drug that inhibits the release of intracellular calcium ions decreases the force of myocardial contractility, thereby decreasing the oxygen demand.

65) Select the correct statement about cardiac output. A) If a semilunar valve were partially obstructed, the end systolic volume in the affected ventricle would be decreased. B) Decreased venous return will result in increased end diastolic volume. C) A slow heart rate increases end diastolic volume, stroke volume, and force of contraction. D) Stroke volume increases if end diastolic volume decreases.

C) A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.

17) A condition of rapid and irregular or out-of-phase contraction of heart muscle cells. A) Ectopic focus B) Quiescent period C) Fibrillation D) Ischemia E) Infarction

C) Fibrillation

2) Heart muscle. A) Endocardium B) Parietal layer C) Myocardium D) Epicardium

C) Myocardium

6) An abnormally fast heart rate. A) Bradycardia B) Cardiac reserve C) Tachycardia D) Vagal tone

C) Tachycardia

14) Atrioventricular (AV) valve with three flaps. A) Aortic semilunar valve B) Mitral (bicuspid) valve C) Tricuspid valve D) Pulmonary semilunar valve

C) Tricuspid valve

57) When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ________. A) tracing out where the auricles connect B) locating the base C) noticing the thickness of the ventricle walls D) finding the papillary muscles

C) noticing the thickness of the ventricle walls

69) When does the period of atrial repolarization occur? A) during the T wave B) ventricular contraction C) ventricular depolarization D) during the P wave

C) ventricular depolarization

56) The atrioventricular (AV) valves are closed ________. A) when the ventricles are in diastole B) while the atria are contracting C) when the ventricles are in systole D) by the movement of blood from atria to ventricles

C) when the ventricles are in systole

80) Why is oxygen so much more critical to the heart muscle than to skeletal muscles?

Cardiac muscle cells are highly dependent on oxygen and rely almost exclusively on aerobic respiration. Thus, they cannot tolerate lack of oxygen due to an inadequate blood supply. When there is a forced switch to anaerobic respiration, lactic acid and rising H+ levels impair heart function.

3) Serous layer covering the heart muscle. A) Endocardium B) Parietal layer C) Myocardium D) Epicardium

D) Epicardium

15) Heart muscle is deprived of oxygen. A) Ectopic focus B) Quiescent period C) Fibrillation D) Ischemia E) Infarction

D) Ischemia

12) Prevents backflow into the right ventricle. A) Aortic semilunar valve B) Mitral (bicuspid) valve C) Tricuspid valve D) Pulmonary semilunar valve

D) Pulmonary semilunar valve

5) Heart rate at rest under both autonomic divisions signaling. A) Bradycardia B) Cardiac reserve C) Tachycardia D) Vagal tone

D) Vagal tone

55) Which of the following is NOT part of the intrinsic conduction system of the heart? A) sinoatrial (SA) node B) atrioventricular (AV) node C) bundle branches D) atrioventricular (AV) valve

D) atrioventricular (AV) valve

61) Compared to skeletal muscle, cardiac muscle ________. A) has more nuclei per cell B) lacks striations C) cells are larger than skeletal muscle cells D) has gap junctions that allow it to act as a functional syncytium

D) has gap junctions that allow it to act as a functional syncytium

70) During exercise, which of the following would occur on an electrocardiogram (ECG) compared to an individual at rest? A) the T wave would decrease B) the P-R interval would decrease C) the S-T segment would decrease D) the time from one R to the R of the next heartbeat would decrease

D) the time from one R to the R of the next heartbeat would decrease

88) Asystole is the total absence of ventricular electrical activity. Explain why defibrillation would not be effective in this situation.

Defibrillation is accomplished by electrically shocking the heart, which interrupts its chaotic twitching by depolarizing the entire myocardium. In this case, the ventricles are at a total standstill and defibrillation would not be effective.

16) Death of heart muscle cells. A) Ectopic focus B) Quiescent period C) Fibrillation D) Ischemia E) Infarction

E) Infarction

21) Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.

FALSE

27) Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole.

FALSE

28) Auricles slightly increase blood volume in the ventricles.

FALSE

29) The "lub" sounds of the heart are valuable in diagnosis because they provide information about the function of the heart's pulmonary and aortic semilunar valves.

FALSE

30) Autonomic regulation of heart rate is via two reflex centers found in the pons.

FALSE

31) The papillary muscles contract after the other ventricular muscles so that they can take up the slack on the chordae tendineae before the full force of ventricular contractions sends blood against the atrioventricular (AV) valve flaps.

FALSE

32) An electrocardiogram (ECG) provides direct information about valve function.

FALSE

35) Heart tissue is supplied with nutrients primarily by diffusion from the heart chambers through the myocardium.

FALSE

86) A patient was admitted to the hospital with chest pains. On admission, his pulse was 110 and blood pressure was 96/64. According to his history, his normal pulse rate is usually between 80 and 88 and his blood pressure runs from 120/70 to 130/80. Explain why these changes in BP and HR occur.

Increased heart rate (measured by taking his pulse) without maintaining his normal blood pressure is suggestive of reduced stroke volume. Both a drop in blood volume and a weakened heart could cause this, but the chest pains suggest heart damage. Failure of compensating mechanisms to maintain blood pressure suggests a serious decline in cardiac output

79) Explain the role of pacemaker cells in cardiac tissue.

Pacemaker cells do not maintain a stable resting membrane potential. Instead, they have an unstable resting potential that continuously depolarizes, drifting toward threshold for firing. These spontaneously changing membrane potentials, called pacemaker potentials, initiate the action potentials that trigger the heart's rhythmic contractions.

77) The heart is called a "double pump" because there are two functionally separate circulations. Trace the pathway of each of these circulations and include the following information: heart chambers involved, major blood vessels involved, and general areas through which the blood flows. Begin with the right atrium.

Right atrium to right ventricle to pulmonary trunk to pulmonary arteries to lungs to pulmonary veins (pulmonary circuit pump) - left atrium to left ventricle to aorta to body tissues to venae cavae (systemic circuit pump).

75) Define systole and diastole. Which heart chambers are usually referenced when these terms are used?

Systole is contraction of the muscle. Diastole is relaxation of the muscle. The contraction and relaxation of the ventricles are normally described with the terms systole and diastole.

20) The myocardium receives its blood supply from the coronary arteries.

TRUE

22) Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle.

TRUE

23) Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues.

TRUE

24) Tissues damaged by myocardial infarction are replaced by connective tissue.

TRUE

25) The left side of the heart pumps the same volume of blood as the right.

TRUE

26) When released in large quantities, thyroxine, a thyroid gland hormone, causes a sustained increase in heart rate.

TRUE

33) As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve.

TRUE

34) If the aorta and pulmonary trunk were switched, oxygen rich blood would be pumped from the left ventricle to the lungs.

TRUE

83) A 14-year-old girl undergoing a physical examination prior to being admitted to summer camp was found to have a loud diastolic murmur at the second intercostal space to the left side of the sternum. Explain the reason for the loud heart murmur associated with this girl's condition.

The heart murmur is due to incomplete closure of the pulmonary valve and regurgitation of pulmonary trunk blood during diastole.

78) What two important functions does the intrinsic cardiac conduction system perform?

The important functions of the intrinsic cardiac conduction system are to initiate impulses (pacemaker) and to distribute impulses throughout the heart so that it depolarizes and contracts in an orderly, sequential manner.

84) An older woman complains of shortness of breath and intermittent fainting spells. Her doctor runs various tests and finds that the atrioventricular (AV) node is not functioning properly. What is the suggested treatment?

The suggested treatment is surgery to implant an artificial pacemaker.

81) List the three vessels that bring oxygen-poor blood to the right atrium. Which regions of the body do they serve?

The superior vena cava returns oxygen-poor blood from body regions superior to the diaphragm. The inferior vena cava returns oxygen-poor blood from body areas inferior to the diaphragm. The coronary sinus collects blood draining from the myocardium.