The Pacemaker Potential of the SA Node and the AV Node

Leslie Samuel explains the pacemaker potential of the SA and AV nodes, detailing how these nodes generate impulses that cause the heart to beat automatically. The SA node, located in the right atrium, acts as the heart's primary pacemaker due to its ability to generate signals faster than other nodes. The AV node and Purkinje fibers also play crucial roles in spreading these signals. The video delves into the pacemaker potential mechanism, highlighting the roles of sodium, calcium, and potassium ions in generating action potentials. The episode concludes with a call to visit interactive-biology.com for more resources.

What is the primary role of the SA node in the heart?

• To store calcium ions

• To act as a barrier between atria and ventricles

• To contract and pump blood

• To generate electrical impulses automatically

Where is the SA node located in the heart?

• Right ventricle

• Left ventricle

• Right atrium

• Left atrium

What does the AV node stand for?

• Atrial Ventricular node

• Atrium Ventricle node

• Aortic Valve node

• Automatic Ventricular node

What is the function of Purkinje fibers in the heart?

• To contract the atria

• To spread electrical signals throughout the ventricles

• To generate impulses in the SA node

• To store sodium ions

Which ion has a higher conductance in pacemaker cells of the SA node?

• Calcium

• Chloride

• Potassium

• Sodium

What happens when the pacemaker potential reaches the threshold?

• Chloride channels open

• Potassium channels open

• Calcium channels open

• Sodium channels close

What is the result of the continuous depolarization in the SA node?

• The heart stops beating

• The heart beats automatically

• The heart rate decreases

• The heart contracts irregularly