Heartbeat (Unit 5 Standard B)

Which portion of the EKG corresponds to the repolarization of the atria?

• T wave

• QRS Complex

• P wave

• None of the above. Atrial repolarization is masked by ventricular depolarization

Where is the sinoatrial (SA) node located in the heart?

• The junction between the atria and ventricles

• The wall of the right atrium

• To the right of the inferior vena cava

• At the base of the ventricles

Which term refers to the stage of ventricular systole when the volumes of the ventricles are not changing (e.g. no blood is being ejected) but pressure is still rising?

• End-diastolic volume

• Diastole

• Quiescent

• Isovolumic contraction

Blood enters the ventricle passively during ________.

• atrial systole

• ventricular diastole

• ventricular systole

• isovolumic contraction

The first heart sound represents which portion of the cardiac cycle?

• opening of the atrioventricular valves

• closing of the semilunar valves

• closing of the atrioventricular valves

• closing of the semilunar valves

Which structure of the heart is known as the cardiac pacemaker or the natural pacemaker?

• The atrioventricular (AV) node

• The sinoatrial (SA) node

• The Purkinje fibers

• The bundle branches

Which of the following is not a stage of the action potential in cardiac muscles?

• Initial Closure

• Rapid Depolarization

• Plateau

• Repolarization

The ventricles begin contracting shortly after the peak of the

• R wave

• T wave

• P wave

• Qa wave

As ventricular pressure rises and exceeds pressure in the arteries, what occurs?

• Ventricles relax

• Semilunar valves close

• Semilunar valves open

• Atria relax

Purkinje fibers radiate from the apex towards the base of the heart. As a result, ventricles contract in a wave to push blood ​________.

• The ventricles

• The pulmonary veins

• The atria

• The pulmonary trunk and aorta