Understanding the Heart

Where does the heart's conduction system begin?

• AV Node

• Purkinje Fibers

• SA Node

• Bundle of His

What is the main function of the SA node?

• It serves as a barrier between the atria and ventricles

• It initiates impulses that set the heart's rhythm

• It delays electrical impulses to the ventricles

• It prevents blood flow between the atria and ventricles

How does the AV node contribute to the cardiac cycle?

• It generates all the impulses in the heart

• It delays impulses to allow atria to contract fully

• It prevents ventricular contraction

• It conducts impulses directly to the arteries

What does the QRS complex on an ECG represent?

• Atrial depolarization

• Ventricular depolarization

• Atrial contraction

• Ventricular relaxation

What does the T wave on an ECG indicate?

• Atrial depolarization

• Ventricular depolarization

• Ventricular repolarization

• Atrial contraction

What occurs when the ventricular pressure exceeds atrial pressure?

• The AV valves open

• The semilunar valves close

• The AV valves close

• The ventricles enter diastole

What is the role of the papillary muscles during ventricular systole?

• They prevent AV valve cusps from bulging into the atria

• They generate electrical impulses in the ventricles

• They open the semilunar valves

• They conduct impulses through the AV node

What causes the second heart sound (S2) during a cardiac cycle?

• Opening of the AV valves

• Closing of the AV valves

• Opening of the semilunar valves

• Closing of the semilunar valves

Why is the myocardium of the left ventricle thicker than that of the right ventricle?

• To generate more electrical impulses

• To withstand higher systemic pressure

• To contain more blood volume

• To supply blood to the lungs

What regulates the volume of blood pumped by the heart?

• The AV node

• The brainstem only

• Changes in cellular requirements

• Electrical impulses from the limbs