Back to notes
What occurs during the S-T segment in an ECG?
Press to flip
Plateau in myocardial action potential; ventricles contract and pump blood.
Where is the atrioventricular (AV) node located?
On the other side of the right atrium near the AV valve.
What does the T wave in an ECG represent?
Ventricular repolarization before ventricular relaxation (diastole).
What does the P wave in an ECG represent?
Depolarization of the atria.
During which ECG wave does atrial repolarization occur, and why is it not usually visible?
During the QRS complex; it is obscured by ventricular depolarization.
What is the function of the atrioventricular (AV) bundle (Bundle of His)?
To conduct impulses toward the apex of the heart.
What role do Purkinje fibers play in the cardiac conduction system?
They spread impulses throughout the ventricular myocardium, causing the ventricles to contract.
What is the significance of the S wave in the QRS complex?
It represents the last phase of ventricular depolarization at the base of the heart.
What happens approximately 100 ms after the P wave begins in an ECG?
Atrial contraction (systole) starts.
Where is the sinoatrial (SA) node located in the heart?
Right atrium near the superior vena cava
What is the primary function of the sinoatrial (SA) node?
The SA node is the natural pacemaker of the heart; it initiates the heartbeat and determines the heart rate.
Why does the atrioventricular (AV) node delay electrical impulses?
To ensure complete atrial ejection before ventricular contraction.
Why is the SA node referred to as the natural pacemaker of the heart?
Because it initiates the heartbeat and determines the heart rate.
What does the P-Q segment indicate in an ECG?
The time signals travel from the SA node to the AV node.
What event does the QRS complex in an ECG correspond to?
Ventricular depolarization and the firing of the AV node.
What are the divisions of the atrioventricular (AV) bundle?
Right and left bundle branches.
Previous
Next