How the Heart Contracts: Understanding the Electrical Activity and Heart Arrhythmias

The video tutorial explores the heart's ability to contract independently, driven by pacemaker cells and the sinoatrial (SA) node. It details the heart's conductive pathway, including the atrioventricular (AV) node and the bundle of His, leading to the Purkinje fibers. The tutorial explains the electrocardiogram (ECG) and its role in assessing heart electrical activity. It concludes with a discussion on heart arrhythmias, such as tachycardia and bradycardia, and their potential health implications.

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

• To delay the heart's electrical impulses

• To pump blood throughout the body

• To act as the heart's natural pacemaker

• To supply oxygen to the heart muscle

What role does the atrioventricular (AV) node play in the heart's conduction system?

• It initiates the heartbeat

• It delays the impulse to allow the atria to contract

• It supplies blood to the heart

• It repolarizes the ventricles

Which part of the heart's conduction system is responsible for transmitting impulses to the ventricles?

• Superior vena cava

• Purkinje fibers

• AV node

• SA node

What does the QRS complex on an ECG represent?

• Atrial depolarization

• Atrial repolarization

• Ventricular depolarization

• Ventricular repolarization

What does the T wave on an ECG indicate?

• Atrial repolarization

• Ventricular repolarization

• Ventricular depolarization

• Atrial depolarization

Which condition is characterized by a heart rate exceeding 100 beats per minute?

• Fibrillation

• Tachycardia

• Bradycardia

• Arrhythmia

What is fibrillation in the context of heart function?

• A disorganized and irregular contraction of the heart

• A heart rate below 60 beats per minute

• A regular and organized contraction of the heart

• A slow heart rate