Quiz 3 17.1

A damaged atrioventricular (AV) bundle or atrioventricular (AV) node will primarily affect the length of the: A) P-R interval. B) T wave. C) Q-T interval. D) P wave.

A) P-R interval.

Which of the following can be used to measure heart rate? A) R-R interval B) Q-T interval C) S-T segment D) T wave

A) R-R interval

Which wave on the electrocardiogram (ECG) corresponds with the ventricular ejection phase of the cardiac cycle? A) T wave B) P wave C) R wave D) Q wave

A) T wave

Autorhythmicity in the heart is the responsibility of: A) cardiac pacemaker cells B) contractile cells C) skeletal muscle cells D) smooth muscle cells

A) cardiac pacemaker cells

As ventricular systole begins, all four heart valves are closed during the: A) isovolumetric contraction phase. B) ventricular ejection phase. C) ventricular filling phase. D) isovolumetric relaxation phase.

A) isovolumetric contraction phase.

Which of the following is NOT a population of pacemaker cells in the heart? A) papillary muscles B) Purkinje fiber system C) sinoatrial (SA) node D) atrioventricular (AV) node

A) papillary muscles

Which wave on the electrocardiogram (ECG) corresponds with the ventricular filling phase of the cardiac cycle? A) S-T segment B) P wave C) T wave D) S wave

B) P wave

A damaged right bundle branch will prevent the passage of the action potential to the: A) sinoatrial (SA) node. B) Purkinje fibers in the right ventricle. C) atrioventricular (AV) node. D) atrioventricular (AV) bundle.

B) Purkinje fibers in the right ventricle.

Which part of the electrocardiogram (ECG) would most be affected by abnormally slow A) P wave B) QRS wave C) R-T interval D) T wave

B) QRS wave

What is NOT part of the cardiac conduction system? A) atrioventricular (AV) node B) atrioventricular (AV) valve C) sinoatrial (SA) node D) atrioventricular (AV) bundle

B) atrioventricular (AV) valve

Generally, coronary veins empty into a vessel known as the A) aorta B) coronary sinus C) inferior vena cava D) superior vena cava

B) coronary sinus

When is the S2 heart sound heard? A) ventricular filling B) isovolumetric relaxation phase C) ventricular ejection phase D) isovolumetric contraction phase

B) isovolumetric relaxation phase

A contractile cell with a sustained membrane potential of 0 mV is experiencing the: A) depolarization phase B) plateau phase C) initial repolarization phase D) rapid depolarization phase

B) plateau phase

Which of the following pacemaker cell populations has the fastest intrinsic rate about 60-70 times or more per minute? A) atrioventricular (AV) node B) sinoatrial (SA) node C) atrioventricular (AV) bundle D) Purkinje fiber system

B) sinoatrial (SA) node

Determine the impact if the connection between the sinoatrial (SA) node and the atrioventricular (AV) node becomes blocked. A) the atria will contract more forcefully, B) the ventricular rhythm will not change C) the ventricles will contract more slowly D) the ventricles will contract more quickly

C )the ventricles will contract more slowly

Place the following parts of the cardiac conduction system in the order in which they transmit the action potential 1. atrioventricular (AV) bundle 2. Purkinje fibers 3. sinoatrial (SA) node 4. right and left bundle branches 5. contractile cells of cardiac muscle tissue 6. atrioventricular (AV) node A) 3,1,6,4,5,2 B) 3,6,4,1,2,5 C) 3,6,1,4,2,5 D) 3,1,6,4,2,5

C) 3,6,1,4,2,5

Which wave on the electrocardiogram (ECG) represents ventricular depolarization? A) R-R interval B) P wave C) QRS wave D) T wave

C) QRS wave

On an electrocardiogram (ECG), atrial repolarization is obscured by the: A) T wave. B) P wave. C) QRS wave. D) S-T segment.

C) QRS wave.

What activity is occurring in the heart during the Q-T interval on an electrocardiogram (ECG)? A) The atrial cells are undergoing action potentials. B) The AV node delay occurs as the action potential spreads from the SA node to the atria to the ventricles. C) The ventricular cells are undergoing action potentials. D) The ventricular cells are repolarizing.

C) The ventricular cells are undergoing action potentials.

The long length of the cardiac action potential, at 200-300 msec, allows for: A) a faster heart rate. B) a reduction in strength of the heart's contraction. C) an opportunity for the heart to fill with blood. D) less calcium ions to enter cells.

C) an opportunity for the heart to fill with blood.

The right and left coronary arteries receive blood from the: A) coronary sinus B) pulmonary trunk C) aorta D) superior vena cava

C) aorta

The coronary sinus does NOT receive blood from the: A) small cardiac vein B) great cardiac vein C) brachiocephalic vein D) middle cardiac vein

C) brachiocephalic vein

Coronary circulation involves the delivery of oxygenated blood to the: A) liver B) brain C) heart D) lungs

C) heart

What normally serves as the pacemaker of the entire heart? A) atrioventricular (AV) node B) atrioventricular (AV) bundle C) sinoatrial (SA) node D) Purkinje fiber system

C) sinoatrial (SA) node

The right and left atria depolarize and contract following the arrival of the action potential from the: A) Purkinje fibers. B) atrioventricular (AV) bundle. C) sinoatrial (SA) node. D) atrioventricular (AV) node.

C) sinoatrial (SA) node.

The volume of blood pumped by each ventricle in one heartbeat is known as: A) end-diastolic volume (EDV). B) heart rate (HR). C) stroke volume (SV) D) cardiac output (CO).

C) stroke volume (SV)

Archie has a resting heart rate of 125 beats per minute. Classify his cardiac dysrhythmia. A) bradycardia B) asystole C) tachycardia D) heart block

C) tachycardia

What produces the "lub dub" heart sounds? A) the relaxation of the atria, and then the ventricles B) the sound of blood traveling through the heart C) the vibrations of the ventricular and blood vessel walls when valves shut D) the contraction of the atria, and then the ventricles

C) the vibrations of the ventricular and blood vessel walls when valves shut

Predict the position of the valves during the ventricular ejection phase. A) The AV valves are forced open while both semilunar valves are shut. B) The AV valves and semilunar valves are shut. C) The AV valves and semilunar valves are forced open. D) The AV valves are shut while both semilunar valves are forced open.

D) The AV valves are shut while both semilunar valves are forced open.

The P wave on an electrocardiogram (ECG) represents the depolarization of cells in the: A) atrioventricular (AV) node. B) ventricles. C) sinoatrial (SA) node. D) atria.

D) atria.

What characteristic differentiates cardiac muscle cells from skeletal muscle cells? A) excitability B) striations C) sarcoplasmic reticulum D) intercalated discs

D) intercalated discs

Which two arteries arise from the right coronary artery ? A) the left marginal artery and the right circumflex artery B) the right anterior interventricular artery and the left posterior interventricular artery C) the right anterior interventricular artery and the right circumflex artery D) the right marginal artery and the right posterior interventricular artery

D) the right marginal artery and the right posterior interventricular artery