Heart Node Functions and Pacemakers

The video explores the pacemaker potential in the heart, focusing on the SA and AV nodes. It explains how these nodes generate electrical signals that regulate heartbeats. The video details the movement of ions like sodium, potassium, and calcium across cell membranes, leading to depolarization and repolarization. It also discusses the cycle of ion exchange and what happens if the SA node malfunctions, including the role of the AV node and potential medical interventions.

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

• To filter blood

• To store oxygen

• To generate electrical impulses automatically

• To contract and pump blood

Where is the SA node located in the heart?

• In the left ventricle

• In the right atrium

• In the left atrium

• In the right ventricle

How does the AV node differ from the SA node in terms of location?

• AV node is in the left atrium

• AV node is in the right ventricle

• AV node is in the lower back section of the interatrial septum

• AV node is in the superior vena cava

What happens when sodium ions move into the SA node cells?

• The membrane potential becomes more negative

• The membrane potential becomes more positive

• The cell contracts

• The cell releases calcium

What is the threshold potential for opening voltage-gated calcium channels in the SA node?

• -20 mV

• -40 mV

• -55 mV

• -70 mV

What is the process called when potassium ions rush out of the SA node cells?

• Neutralization

• Hyperpolarization

• Repolarization

• Depolarization

What role does the sodium-potassium pump play in the SA node?

• It restores ion distribution by pumping sodium out and potassium in

• It generates electrical impulses

• It releases calcium

• It contracts the cell

What happens if the SA node stops functioning properly?

• The heart stops immediately

• The heart rate increases

• The AV node takes over but at a slower rate

• The heart rate remains unchanged

What is the typical heart rate set by the AV node if the SA node fails?

• 40-60 beats per minute

• 60-80 beats per minute

• 80-100 beats per minute

• 20-40 beats per minute

In what situation might a patient require an artificial pacemaker?

• When the heart rate is too fast

• When the SA node fails and the AV node cannot compensate adequately

• When the AV node is functioning normally

• When the SA node is functioning normally