Understanding the Cardiac Conduction System

What initiates the heart's electrical stimulation?

• Bundle of His

• Purkinje fibers

• Atrioventricular node

• Sinoatrial node

What is the primary function of the sinoatrial node?

• To contract the ventricles

• To close the heart valves

• To regulate blood pressure

• To set the pace of the heartbeat

How does the signal from the SA node affect the atria?

• It stops their contraction

• It causes atrial systole

• It causes them to relax

• It has no effect

Where is the AV node located?

• Between the ventricles

• Between the atria and ventricles

• Outside the heart

• Inside the SA node

What role does the AV node play in heart contraction?

• It contracts the atria

• It pumps blood to the body

• It relays the signal to the ventricles

• It generates the initial heartbeat

What is the function of the bundle of His?

• To pump blood

• To relax the heart

• To receive signals from the AV node

• To separate the signal into left and right branches

During atrial systole, what happens to the ventricles?

• They contract

• They eject blood

• They relax

• They fill with blood

How do Purkinje fibers contribute to heart function?

• By spreading the signal to cardiac muscle cells

• By filtering blood

• By cooling the heart

• By producing hormones

What is the all-or-none law in the context of heart contraction?

• The heart contracts at varying strengths

• The heart either contracts fully or not at all

• Only some parts of the heart contract

• The heart contracts randomly

What is the significance of ventricular systole?

• It signals the heart to stop beating

• It relaxes the heart muscles

• It causes the atria to contract

• It forces blood out of the ventricles