Lab Exercise 4 on Electrophysiology of the Heart

What are autorhythmic cells also known as?

• Blood cells

• Muscle cells

• Pacemaker cells

• Nerve cells

What does the cardiac conduction system include?

• Blood vessels

• Pacemaker cells

• Muscle fibers

• Nerve endings

What is the significance of the atrioventricular bundle in the cardiac conduction system?

• It initiates the heartbeat.

• It conducts signals from the AV node to the bundle branches.

• It contracts the atria.

• It measures heart rate.

What is the primary function of the left atrium in the heart?

• To pump blood to the lungs

• To receive oxygenated blood from the lungs

• To pump blood to the body

• To regulate heart rate

What does PNS do to heart rate by opening K+ channels?

• Decreases heart rate

• Increases heart rate

• Stabilizes heart rate

• No effect on heart rate

What is the effect of the SNS on action potentials in pacemaker cells?

• Causes them to fire faster

• Causes them to fire slower

• Stabilizes their firing rate

• No effect on their firing rate

What is the primary effect of positive chronotropic agents?

• Increase in heart rate

• Decrease in heart rate

• Stabilization of heart rate

• No effect on heart rate

What is the purpose of the segments in an ECG?

• To measure heart rate

• To indicate periods of no electrical activity

• To show blood flow

• To display oxygen levels

What is the typical heart rate range when the AV node paces the heart?

• 60-80 bpm

• 70-90 bpm

• 40-60 bpm

• 50-70 bpm

Which rhythm is associated with a rapid and irregular heartbeat?

• Sinus Rhythm

• Atrial Fibrillation

• Heart Block

• Nodal Rhythm