Deck 7: The Peripheral Nervous System: Efferent Division

Question 1

When ECF K⁺ levels fall below normal, the heart becomes weak, flaccid, and dilated.

Answer 1

True

Question 2

Parasympathetic stimulation of the AV node increases the speed of transmission of the impulse through the AV node.

Answer 2

False

Question 3

Sympathetic stimulation of the heart increases calcium permeability.

Answer 3

True

Question 4

The tricuspid prevents regurgitation of blood from the right ventricle back into the right atrium.

Question 5

Atrial repolarization does not occur.

Question 6

Stroke volume can vary by alterations in both intrinsic and extrinsic control mechanisms.

Question 7

Atrial systole lasts throughout ventricular systole.

Question 8

The semilunar valves are positioned between the atria and ventricles.

Question 9

The T wave represents the depolarization of the ventricles.

Question 10

With 2:1 rhythm, the atrial rate is very rapid and the ventricular rate is normal or above normal, whereas with 2:1 block, the atrial rate is normal but the ventricular rate is below normal

Question 11

Ventricular filling occurs more rapidly early in diastole than it does later in diastole.

Question 12

The end-diastolic volume is the maximum amount of blood in the ventricle after ventricular filling is complete.

Question 13

Angina pectoris develops from the abundance of oxygen of blood in the coronary circulation.

Question 14

The heart valves are innervated by the autonomic nervous system.

Question 15

The bundle of His and Purkinje system facilitate the rapid spread of the action potential throughout the ventricles.

Question 16

The only point of electrical contact between the atria and the ventricles is the AV valve.

Question 17

The AV valve controls the amount of blood entering the atrium from the venous system.

Question 18

According to the Frank-Starling law of the heart, the greater the stroke volume, the smaller the subsequent end-diastolic volume will be, because as more blood is squeezed out, the heart cannot fill as completely during the next diastole.

Question 19

The right ventricle pumps out blood low in oxygen content, whereas the left ventricle pumps out blood high in oxygen content.

Question 20

Parasympathetic stimulation slows the rate of depolarization of the SA node and thus decreases the heart rate.

Question 21

The second heart sound is due to closure of the AV valves.

Question 22

HDLs have less protein than LDLs.

Question 23

The ESV of the heart averages about 140 mL.

Question 24

The ECG is an actual recording of cardiac electrical activity.

Question 25

The SA node is the pacemaker of the heart.

Question 26

The first heart sound signals the onset of ventricular systole.

Question 27

The action potential impulse passes through the AV node between the P wave and QRS complex.

Question 28

Left-sided congestive heart failure can lead to pulmonary edema.

Question 29

The functional syncytia of the myocardium are offered by the intercalated discs.

Question 30

The plateau phase of the action potential in a contractile cardiac muscle cell occurs as a result of activation of slow Ca²⁺ channels.

Question 31

Sympathetic stimulation increases the heart rate.

Question 32

One important function of the intrinsic control of the heart (Frank-Starling law of the heart) is to maintain the left and right cardiac outputs in balance.

Question 33

Diastole refers to the period of cardiac relaxation.

Question 34

Most ventricular filling is accomplished during atrial contraction.

Question 35

The rate of appearance of the QRS and T waves is unaffected if the heart develops a complete heart block.

Question 36

The heart is posterior to the sternum.

Question 37

A pacemaker potential depends on the increased inward current of calcium ions.

Question 38

Ventricular ejection occurs once the afterload has been overcome.

Question 39

Gap junctions are absent between atrial and ventricular cells.

Question 40

The stroke volume is the total volume of blood ejected by both ventricles per minute.

Question 41

The EDV of the heart averages about 65 mL.

Question 42

The semilunar valves close to prevent the backflow of blood into the ventricles.

Question 43

The function of the chordae tendineae and papillary muscles is to hold the AV valves wide open during diastole to ensure complete ventricular filling.

Question 44

The action potential spreads through the atria by gap junctions, but there are no gap junctions present in the ventricles, so the impulse must be propagated throughout the ventricular myocardium by the bundle of His and Purkinje system.

Question 45

Hypertension decreases the afterload and increases the preload.

Question 46

The aortic valve prevents backflow of blood from the aorta into the left ventricle during ventricular diastole.

Question 47

Cardiac tamponade refers to failure of the AV node to transmit the action potential from the atria to the ventricles.

Question 48

Most blood flow through the coronary vessels occurs during ventricular systole when the heart is driving blood forward.

Question 49

The AV and semilunar valves are never open at the same time.

Question 50

The amount of blood pumped out of the heart during each beat is known as the cardiac output.

Question 51

Increased EDV results in decreased stroke volume.

Question 52

Cardiac muscle receives its blood supply primarily during ventricular systole when blood is being pumped out into the aorta.

Question 53

Stroke volume is determined by the extent of venous return and parasympathetic activity.

Question 54

Pacemaker activity by the Purkinje fibres is an example of an ectopic focus.

Question 55

The cardiac output is the same as the cardiac reserve of the heart.

Question 56

Not all forms of LDL are equally harmful to the heart.

Question 57

The long refractory period of cardiac muscle prevents tetanic contractions of the heart.

Question 58

The ventricles always depolarize at the same rate as the SA node depolarizes.

Question 59

According to the Frank-Starling law of the heart, the shorter the initial length of the cardiac muscle fibres prior to contraction, the more forceful will be the subsequent contraction because the fibres are already partially contracted.

Question 60

Normally, the stroke volume of the right side of the heart is the same as the stroke volume of the left side of the heart.

Question 61

The heart utilizes glucose almost exclusively for energy production.

Question 62

The refractory period in cardiac muscle is much shorter than the refractory period in skeletal muscle to ensure that the heart can quickly be restimulated to produce alternate periods of contraction and relaxation.

Question 63

The atria and the ventricles contract at the same time to ensure efficient pumping action.

Question 64

Which of these statements correctly describes extrasystole of the heart?

A)The heart beats too slowly.
B)The heart fills with too much blood.
C) The heart has a complete heart block.
D) The heart produces a premature beat.

Question 65

The average resting heart rate is normally established by the rhythm of the AV node.

Question 66

Contraction of the spirally arranged cardiac muscle fibres produces a wringing effect for efficient pumping.

Question 67

The pulmonary circulation carries oxygenated blood from the lungs to the body tissues.

Question 68

Which of these statements correctly describes the AV nodal delay?

A)It ensures that the atria contract and empty their contents into the ventricles prior to ventricular systole.
B)It ensures that the ventricles contract prior to atrial systole.
C) It ensures that tetanic contraction of cardiac muscle is impossible.
D) It is shortened by parasympathetic stimulation.

Question 69

The right half of the heart pumps blood through the pulmonary circuit. Through which circuit does the left half pump blood?

A)diastolic
B)pulmonary
C) systolic
D) systemic

Question 70

Which structures join adjacent cardiac muscle cells end-to-end in the ventricles?

A)intercalated discs
B)sarcomeres
C) Purkinje fibres
D) sinoatrial nodes

Question 71

Which of these criteria must be met for the heart to function efficiently?

A)Excitation and consequently contraction of the cardiac muscle fibres of each heart chamber should be coordinated to ensure efficient pumping.
B)The ventricles should be excited and contract before the onset of atrial contraction to ensure that ventricular filling is complete.
C) The right side of the heart should contract first to ensure that oxygenated blood is delivered to the heart before the left side contracts.
D) The fluid pressure in the pericardial cavity must be high for the heart to function efficiently

Question 72

Which of the following is the cranial nerve of the parasympathetic nervous system that signals the heart?

A)cardiac
B)coronary
C) trigeminal
D) vagus

Question 73

All of the blood within the ventricles is ejected during ventricular systole.

Question 74

Cardiac output is stroke volume times the heart rate.

Question 75

Twelve complete ECG patterns are recorded from a subject over 10 seconds. If this pattern continues, what is the rate of the heartbeat in the subject?

A)60 beats per minute
B)72 beats per minute
C) 90 beats per minute
D) 108 beats per minute

Question 76

The heart muscle receives its oxygen and nutrients directly from the blood within its chambers during ventricular diastole.

Question 77

Arteries carry blood toward the ventricles.

Question 78

The extent of ventricular filling is the preload of the heart, whereas the magnitude of the arterial blood pressure is the afterload of the heart.

Question 79

The heart undergoes tetanic contraction during sympathetic stimulation to squeeze out more blood.

Question 80

Complete heart block results from a damaged AV node.