Chapter 20

Question 1

1) Which of the following terms identifies the anatomical region found between the lungs that extends from the sternum to the vertebral column and from the first rib to the diaphragm?
a) Epicardium
b) Abdominal cavity
c) Pericardium
d) Mediastinum
e) Thoracic cavity

Answer 1

d) Mediastinum

Question 2

2) The membrane that surrounds and protects the heart is called the
a) pericardium.
b) pleura.
c) myocardium.
d) mediastinum.
e) endocardium.

Answer 2

a) pericardium.

Question 3

3) The apex of the heart is normally pointed
a) at the midline.
b) to the left of the midline.
c) to the right of the midline.
d) is different for males and females
e) posteriorly.

Answer 3

b) to the left of the midline.

Question 4

4) The outermost layer of the pericardium, which consists of inelastic dense irregular connective tissue, is called the
a) parietal layer of pericardium.
b) serous pericardium.
c) fibrous pericardium.
d) epicardium.
e) endocardium.

Answer 4

c) fibrous pericardium.

Question 5

5) Which of the following is used to reduce friction between the layers of membranes surrounding the heart?
a) Synovial fluid
b) Endocardium
c) Pleural fluid
d) Pericardial fluid
e) Capillary endothelium

Answer 5

d) Pericardial fluid

Question 6

6) Which layer of the heart wall consists of mesothelium and connective tissue?
a) Epicardium
b) Myocardium
c) Endocardium
d) Fibrous pericardium
e) None of the answer selections are correct

Answer 6

a) Epicardium

Question 7

7) Which layer of the heart wall consists of cardiac muscle tissue?
a) Epicardium
b) Pericardium
c) Myocardium
d) Endocardium
e) Hypocardium

Answer 7

c) Myocardium

Question 8

8) Identify the pouch-like structure that increases the total filling capacity of the atrium.
a) Ventricle
b) Coronary sulcus
c) Fossa ovalis
d) Interatrial septum
e) Auricle.

Answer 8

e) Auricle.

Question 9

9) Identify the groove found on the surface of the heart and marks the boundary between the right and left ventricles.
a) Coronary sulcus
b) Anterior interventricular sulcus
c) Posterior interventricular sulcus
d) Coronary sinus
e) Anterior intraventricular sulcus

Answer 9

b) Anterior interventricular sulcus

Question 10

10) Identify the muscular ridges that are found on the anterior wall of the right atrium and extend into the auricles.
a) Pectinate muscles
b) Trabeculae carneae
c) Coronary sulci
d) Papillary muscles
e) Chordae tendinae

Answer 10

a) Pectinate muscles

Question 11

11) Through which structure does blood pass from the right atrium to the right ventricle?
a) Bicuspid valve
b) Interventricular septum
c) Tricuspid valve
d) Mitral valve
e) Ascending aorta

Answer 11

c) Tricuspid valve

Question 12

12) What type of tissue comprises the valves of the heart?
a) Dense connective tissue
b) Areolar connective tissue
c) Hyaline cartilage
d) Cardiac muscle tissue
e) Adipose tissue

Answer 12

a) Dense connective tissue

Question 13

13) Blood leaving the left ventricle passes through which of the following structures?
a) Right atrium
b) Interventricular septum
c) Bicuspid valve
d) Aortic semilunar valve
e) Pulmonary semilunar valve

Answer 13

d) Aortic semilunar valve

Question 14

14) Identify the structure found in a fetus that allows blood to flow directly from the pulmonary trunk into the aorta.
a) Fossa ovalis
b) Foramen ovale
c) Trabeculae carneae
d) Descending aorta
e) Ductus arteriosus

Answer 14

e) Ductus arteriosus

Question 15

15) Why is the myocardium of the left ventricle thicker than the myocardium of the right ventricle?

Answer 15

Solution: The left ventricle muscular wall is thicker than the right ventricle because it has to generate higher pressure to overcome the greater resistance of the longer systemic circulation route versus the shorter pulmonary circulation route.

Question 16

16) Contraction of the ventricles of the heart leads to blood moving directly
a) into arteries.
b) into capillaries.
c) into veins.
d) through an atrioventricular valve.
e) through the apex.

Answer 16

a) into arteries.

Question 17

17) Contraction of the atria of the heart leads to blood moving directly
a) into auricles.
b) into arteries.
c) into veins
d) through atrioventricular valves
e) through semilunar valves.

Answer 17

d) through atrioventricular valves

Question 18

18) Which valve below prevents blood from flowing back into the right ventricle?
a) Tricuspid valve
b) Bicuspid valve
c) Pulmonary semilunar valve
d) Aortic semilunar valve
e) Mitral valve

Answer 18

c) Pulmonary semilunar valve

Question 19

19) Explain how the heart pumps blood into two separate closed circuits that are arranged in series.

Answer 19

Solution: The two circuits are the pulmonary and systemic circuits.Venous blood from the systemic circulation enters the right atrium. The blood moves from the right atrium into the right ventricle of the heart, which pumps blood through the pulmonary circuit eventually filling the left atrium. The blood moves from the left atrium into the left ventricle of the heart, which pumps blood through the systemic circuit back into the right atrium.

Question 20

20) What of the following chambers of the heart contain deoxygenated blood?
a) Left atrium and left ventricle
b) Left atrium only
c) Right atrium and right ventricle
d) Right ventricle only
e) Left atrium and right ventricle

Answer 20

c) Right atrium and right ventricle

Question 21

21) Which of the following blood vessel is used to distribute oxygenated blood to the myocardium?
a) Coronary artery
b) Coronary vein
c) Coronary sinus
d) Vena cava
e) Myocardial vein

Answer 21

a) Coronary artery

Question 22

22) Cardiac muscle fibers are electrically connected to neighboring fibers by
a) desmosomes.
b) tight junctions.
c) gap junctions.
d) interneurons.
e) chordae tendinae.

Answer 22

c) gap junctions.

Question 23

23) Which of the following type of muscle contains the largest number of mitochondria per cell?
a) Smooth muscle
b) Skeletal muscle
c) Cardiac muscle
d) All the muscle types contain approximately the same number.
e) Mitochondria are not found in muscle cells.

Answer 23

c) Cardiac muscle

Question 24

24) Briefly describe why cardiac tissue cannot repair itself after damage?

Answer 24

Solution: Cardiac muscle lacks stem cells and mature cardiac muscle fibers cannot go through mitosis.

Question 25

25) Which network of specialized cardiac muscle fibers provide a path for each cycle of cardiac excitation to progress through the heart?
a) Systemic circuit
b) Intercalated discs
c) Cardiovascular center
d) Cardiac conduction system
e) Pulmonary circuit

Answer 25

d) Cardiac conduction system

Question 26

26) Which of the following correctly lists the sequence of structures that a cardiac action potential follows in order to excite normal contraction of the heart?
a) Bundle of His, Purkinje fibers, Atrioventricular (AV) node
b) Sinoatrial (SA) node, Purkinje fibers, AV node, Bundle of His
c) Purkinje fibers, AV node, SA node, Bundle of His
d) SA node, AV node, Bundle of His, Purkinje fibers
e) Bundle of His, SA node, AV node, Purkinje fibers

Answer 26

d) SA node, AV node, Bundle of His, Purkinje fibers

Question 27

27) In comparison to skeletal muscle fibers, the contractile fibers of the heart are depolarized for _____ period of time.
a) a shorter
b) a longer
c) the same

Answer 27

b) a longer

Question 28

28) The volume of blood ejected from the left ventricle into the aorta each minute is called the
a) cardiac output.
b) cardiac input.
c) stroke volume.
d) heart rate.
e) pulse pressure.

Answer 28

a) cardiac output.

Question 29

29) Which term refers to the period of time during a cardiac cycle when contraction of a chamber occurs and pressure within the chamber rises?
a) filling
b) systole
c) repolarization
d) diastole
e) fibrillation

Answer 29

b) systole

Question 30

30) During which of following periods does the largest volume of blood enter the arteries?
a) atrial diastole
b) ventricular diastole
c) atrial systole
d) ventricular systole

Answer 30

d) ventricular systole

Question 31

31) The second heart sound (dupp) closely follows which of the events listed below?
a) Valvular stenosis
b) Semilunar valves opening
c) Atrioventricular valves closing
d) Semilunar valves closing
e) Atrioventricular valves opening

Answer 31

d) Semilunar valves closing

Question 32

32) Which structure in the heart initiates action potentials that stimulate contraction of the heart at constant rate of about 100 beats per minute?
a) Cardiac accelerator nerves
b) Atrioventricular node
c) Cardiovascular center
d) Sinoatrial node
e) Bundle of His

Answer 32

d) Sinoatrial node

Question 33

33) Stimulation of which nerve reduces heart rate?
a) Cardiac accelerator nerve
b) Hypoglossal nerve
c) Spinal accessory
d) Vagus nerve
e) Phrenic nerve

Answer 33

d) Vagus nerve

Question 34

34) Which of the following would lead to a decreased heart rate?
a) Increased norepinephrine release
b) Increased thyroid hormone release
c) Increased potassium levels in plasma
d) Increased calcium levels in plasma
e) Increased sympathetic stimulation

Answer 34

c) Increased potassium levels in plasma

Question 35

35) Which part of the brain contains the cardiovascular center that regulates heart rate?
a) Midbrain
b) Cerebrum
c) Medulla oblongata
d) Cerebellum
e) Thalamus

Answer 35

c) Medulla oblongata

Question 36

36) Which wave in an electrocardiogram represents repolarization of the ventricles?
a) R wave
b) T wave
c) S wave
d) P wave
e) Q wave

Answer 36

b) T wave

Question 37

37) Which of the following selections lists conditions that would lead to increased stroke volume?
a) increased preload, increased afterload, increased contractility
b) decreased preload, decreased afterload, decreased contractility
c) increased preload, decreased afterload, increased contractility
d) decreased preload, increased afterload, increased contractility
e) increased preload, increased afterload, decreased contractility

Answer 37

c) increased preload, decreased afterload, increased contractility

Question 38

38) Which of the following electrocardiogram (EKG) waves represents atrial depolarization?
a) R wave
b) T wave
c) S wave
d) P wave
e) Q wave

Answer 38

d) P wave

Question 39

39) Which portion of the heart wall is responsible for the pumping action?
a) E
b) F
c) G
d) H
e) I

Answer 39

e) I

Question 40

40) In the diagram, where are the trabeculae carneae?
a) D
b) E
c) F
d) G
e) H

Answer 40

d) G

Question 41

41) In the diagram, where is the left auricle of the left atrium?
a) C
b) F
c) G
d) H
e) I

Answer 41

c) G

Question 42

42) In the diagram, which labeled structure prevents blood flow from the right ventricle back into the right atrium?
a) A
b) B
c) C
d) D
e) E

Answer 42

b) B

Question 43

43) In the diagram, which labeled structure is the pulmonary semilunar valve?
a) B
b) D
c) E
d) A
e) None of these choices

Answer 43

d) A

Question 44

44) In the diagram, which labeled structures are atrioventricular valves?
a) B only
b) D only
c) A and C
d) B and D
e) A, B, C and D

Answer 44

d) B and D

Question 45

45) Describe what is happening during the phase of the cardiac action potential labeled 2 in the diagram.

Answer 45

Solution: Phase 2 is the plateau phase which occurs due to opening of slow voltage-gated calcium channels, which allow continued inflow of Ca2+ from ICF into the cytosol. This continuous inflow of Ca+2 causes sustained depolarization of the cardiac muscle cells.

Question 46

46) Briefly describe what is happening at stage of the ECG labeled 5 in the diagram.

Answer 46

Solution: The contractile fibers of the ventricles are repolarizing, which generates the T wave in the ECG.

Question 47

47) Which phases of a heartbeat shown in the diagram involve repolarization of the heart’s four chambers?
a) 1 and 4
b) 2 and 4
c) 4 and 6
d) 1, 3, and 5
e) 1, 2, 4 and 6
f) 3 and 5

Answer 47

f) 3 and 5

Question 48

48) Which of the labeled diagrams shows coarctation of the aorta?
a) A
b) B
c) C
d) D
e) E

Answer 48

a) A

Question 49

49) Which of the labeled diagrams shows an atrial septal defect?
a) A
b) B
c) C
d) D
e) E

Answer 49

c) C

Question 50

50) Which of the labeled steps in the diagram represent formation of the primitive heart tube?
a) A
b) B
c) C
d) D
e) E

Answer 50

c) C

Question 51

51) Which of the labeled steps in the diagram represent formation of the endocardial tubes?
a) A
b) B
c) C
d) D
e) E

Answer 51

b) B

Question 52

52) Which blood vessel shown in the figure carries oxygenated blood to the lower thoracic cavity and the abdominal cavity of the body?
a) A
b) B
c) E
d) F
e) H

Answer 52

d) F

Question 53

53) Which labeled structure shown in the diagram is a remnant of fetal circulation that is not directly involved in adult circulation?
a) A
b) B
c) H
d) D
e) E

Answer 53

d) D

Question 54

54) Which labeled blood vessel in the diagram is an artery carrying deoxygenated blood?
a) A
b) B
c) C
d) E
e) I

Answer 54

d) E

Question 55

55) Which labeled blood vessel shown in the diagram is the left common carotid artery?
a) A
b) B
c) E
d) F
e) H

Answer 55

a) A

Question 56

56) Which labeled structure shown in the diagram is a pouch-like extension that serves to slightly increase the capacity of an atrium?
a) F
b) E
c) G
d) I
e) D

Answer 56

c) G

Question 57

57) What labeled structure in the figure is the ligamentum arteriosum?
a) A
b) B
c) C
d) D

Answer 57

d) D

Question 58

58) What labeled structure in the figure increases the blood volume capacity of an atrium?
a) B
b) G
c) D
d) F

Answer 58

b) G

Question 59

59) Which structure in the figure is labeled B?
a) left common carotid artery
b) left subclavian artery
c) left pulmonary vein
d) mitral valve

Answer 59

b) left subclavian artery

Question 60

60) Which structure in the figure is labeled A?
a) left common carotid artery
b) left subclavian artery
c) left pulmonary vein
d) mitral valve

Answer 60

a) left common carotid artery

Question 61

61) Which labeled structure in the figure acts as the natural pacemaker of the heart?
a) A
b) B
c) C
d) D
e) E

Answer 61

a) A

Question 62

62) Which labeled structure in the figure is the AV node?
a) A
b) B
c) C
d) D
e) E

Answer 62

b) B

Question 63

63) Which labeled structure in the figure represents the only potential pathway for conducting action potentials from the atria to the ventricles?
a) A
b) B
c) C
d) D
e) E

Answer 63

c) C

Question 64

64) Which labeled structure in the figure carries the cardiac action potential directly into the contractile fibers of the ventricular myocardium?
a) A
b) B
c) C
d) D
e) E

Answer 64

c) C

Question 65

65) Discuss the common nutrient sources used by cardiac muscle to produce ATP in a resting individual.

Answer 65

Solution: At rest, the heart relies exclusively on aerobic cellular respiration. At rest, the heart’s ATP comes mainly from oxidation of fatty acids (60%), and glucose (35%) with smaller contributions from lactic acid, amino acids, and ketone bodies.

Question 66

66) Define arrhythmia and discuss different categories of arrhythmias.

Answer 66

Solution: The term arrhythmia or dysrhythmia refers to an abnormal rhythm as a result of a defect in the conduction system of the heart. Arrhythmias are categorized by their speed, rhythm, and origination of the problem. Bradycardia refers to a slow heart rate (blow 50 bpm); tachycardia refers to a rapid heart rate (over 100 bpm); and fibrillation refers to rapid, uncoordinated heartbeats. Arrhythmias that originate in the atria are called supraventricular or atrial arrhythmias; those that originate in the ventricles are called ventricular arrhythmias.

Question 67

67) Cardiac output is the volume of blood ejected from the _____ ventricle into the _____ each minute.
a) left, aorta
b) right, aorta
c) left or right, aorta or pulmonary trunk
d) right, pulmonary trunk
e) both left and right aorta are correct

Answer 67

c) left or right, aorta or pulmonary trunk

Question 68

68) The difference between a person’s maximum cardiac output and resting cardiac output is called the
a) stroke volume.
b) peripheral resistance.
c) afterload.
d) cardiac reserve.
e) venous return.

Answer 68

d) cardiac reserve.

Question 69

69) What is the function of the foramen ovale during fetal life?
a) Allowing blood to flow directly from the right atrium into the left atrium.
b) Allowing blood to flow directly from the right ventricle into the left ventricle.
c) Serves as a valve in the vena cava to regulate venous blood flow.
d) Prevents back flow of blood from aorta into the left ventricle.
e) Prevents back flow of blood from pulmonary trunk into the right ventricle.

Answer 69

a) Allowing blood to flow directly from the right atrium into the left atrium.

Question 70

70) Isovolumetric contraction is the phase of the cardiac cardiac cycle in which
a) the semilunar valves are open.
b) ventricular repolarization occurs.
c) atrial depolarization occurs.
d) oxygenated blood leaves the heart into the systemic circulation.
e) ventricular pressure increases and ventricular volume remains the same.

Answer 70

c) atrial depolarization occurs.

Question 71

71) Which of the following chambers of the heart is surrounded by the thickest layer of myocardium?
a) right atrium
b) left atrium
c) right ventricle
d) left ventricle
e) right auricle

Answer 71

d) left ventricle

Question 72

72) Heart murmurs are often heard in individuals with abnormalities in the _____ of the heart.
a) valves
b) myocardium
c) SA node
d) AV node
e) endocardium

Answer 72

a) valves

Question 73

73) In comparison to a sedentary individual, a well-trained athlete will usually have all the following characteristics EXCEPT
a) a higher cardiac reserve.
b) a higher resting cardiac output.
c) a higher stroke volume.
d) hypertrophy of the heart.
e) resting bradycardia.

Answer 73

b) a higher resting cardiac output.

Question 74

74) During heart transplants, the _____ nerves are severed resulting in a faster resting heart rate (approximately 100 beats per minute) after the transplant.
a) glossopharyngeal
b) cardiac accelerator
c) vagus
d) phrenic
e) cervical spinal

Answer 74

c) vagus

Question 75

75) A corrective cardiac procedure in which a large piece of a patient’s own latissimus dorsi muscle is wrapped around the heart and stimulated by an implanted pacemaker to assist the pumping action of a damaged heart.
a) myocardial infarction
b) tetrology of Fallot
c) cardiomyopathy
d) cardiomegaly
e) cardiomyoplasty

Answer 75

e) cardiomyoplasty