heartcycle 1

What is the sinoatrial node (SA node) known as?

The SA node is known as the pacemaker of the heart.

What role does the SA node play in the heart?

It generates action potentials that initiate electrical excitations independently.

What does the term 'AV node' stand for?

Atrioventricular node.

What is the function of the AV node?

It collects the electrical signal from the atria before sending it to the ventricles.

What are the bundle branches responsible for?

They spread the electrical signal down to the ventricles.

What are Purkinje fibers?

They transmit the electrical signal to the ventricular muscle, causing contraction.

What direction do the ventricles contract?

From the apex back up towards the atria.

What is the direction of blood flow during ventricular contraction?

Blood is pushed out of the ventricles towards the aorta and pulmonary trunk.

What does an electrocardiogram (ECG or EKG) measure?

It measures the electrical activity of the heart.

What is recorded during the P wave of an EKG?

The electrical excitation of the atria.

What does the QRS complex represent in an EKG?

The beginning of ventricular excitation.

What happens during the T wave of an EKG?

The ventricles complete their contraction and shift into repolarization.

What is the right atrioventricular valve commonly referred to as?

The right AV valve.

What is the function of the pulmonary valve?

It allows blood to pass from the right ventricle into the pulmonary trunk.

What is unique about the pulmonary arteries?

They are the only arteries that carry deoxygenated blood away from the heart.

From where does blood collect before entering the right atrium?

From the superior and inferior vena cava.

What is the role of the coronary circulation?

To deliver blood to the heart tissue.

Where do the coronary arteries originate?

From the first branch off of the aorta.