Dr. Mike explains the cardiac conduction system, focusing on how electrical currents move through the heart muscle to trigger contraction. The sinoatrial node initiates this process, setting the heart's rhythm. The video details how depolarization spreads through the atria and ventricles, and how this is captured on an ECG. The role of the atrioventricular node and the Bundle of His in conducting electrical signals is also covered, along with the concepts of depolarization and repolarization, which are crucial for heart function.

What is the primary function of the cardiac conduction system?

• To supply oxygen to the heart muscle

• To remove waste products from the heart

• To pump blood through the body

• To generate electrical impulses that regulate heartbeats

What is the term used to describe the change from a negative to a positive charge in heart muscle cells?

• Hyperpolarization

• Repolarization

• Polarization

• Depolarization

What is the role of the sinoatrial (SA) node in the heart?

• To act as the heart's pacemaker

• To reset the heart's electrical charge

• To contract the ventricles

• To separate the atria from the ventricles

What is the typical heart rate set by the SA node?

• 120 to 140 beats per minute

• 100 to 120 beats per minute

• 60 to 100 beats per minute

• 40 to 60 beats per minute

What does an electrocardiogram (ECG/EKG) measure?

• Oxygen levels in the blood

• Blood pressure

• Heart rate

• Electrical activity of the heart

What is the function of the atrioventricular (AV) node?

• To initiate the heartbeat

• To contract the atria

• To reset the heart's electrical charge

• To delay the electrical impulse before it reaches the ventricles

What are the specialized fibers that carry the electrical impulse through the ventricles called?

• AV node

• Purkinje fibers

• Bundle of His

• SA node

Why does the left side of the heart produce a larger spike on an ECG?

• It has more electrical activity

• It is closer to the ECG leads

• It has thicker muscle tissue

• It contracts more forcefully

What is the term for the process of resetting the heart's electrical charge to negative?

• Depolarization

• Polarization

• Hyperpolarization

• Repolarization

What does the QRS complex on an ECG represent?

• Atrial repolarization

• Atrial depolarization

• Ventricular depolarization

• Ventricular repolarization