EKG certification Certification EKG Cardiac Anatomy & Physiology 1

Question 1

Where is the sinoatrial (SA) node located in the heart?

Accepted Answer

In the upper right atrium near the opening of the superior vena cava

Answer

The SA node sits in the upper wall of the right atrium, close to where the superior vena cava enters. It acts as the heart's primary pacemaker, initiating the electrical impulse that triggers each heartbeat.

Question 2

What does the QRS complex on an EKG primarily represent?

Accepted Answer

Ventricular depolarization

Answer

The QRS complex reflects the rapid electrical depolarization spreading through the ventricular myocardium, which triggers ventricular contraction. Atrial depolarization is represented by the P wave, while repolarization appears as the T wave.

Question 3

Which structure is responsible for delaying the electrical impulse between the atria and ventricles?

Accepted Answer

Atrioventricular (AV) node

Answer

The AV node, located in the lower interatrial septum, intentionally slows conduction to allow the atria to finish contracting and the ventricles to fill with blood before ventricular depolarization begins. This delay is visible as the PR segment on the EKG.

Question 4

The left ventricle has a thicker myocardial wall than the right ventricle primarily because it must:

Accepted Answer

Pump blood against the high resistance of the systemic circulation

Answer

The left ventricle pumps oxygenated blood through the aorta to the entire systemic circulation, which has much higher vascular resistance than the pulmonary circuit. Greater wall thickness generates the force needed to overcome that resistance.

Question 5

Which vessels supply oxygenated blood directly to the myocardium?

Accepted Answer

Coronary arteries

Answer

The right and left coronary arteries arise from the aortic root just above the aortic valve and branch across the heart surface to deliver oxygenated blood to the myocardium itself. Impaired flow in these vessels is the basis of ischemic heart disease.

EKG certification Practice Test

EKG certification Practice Test

EKG certification Certification EKG Cardiac Anatomy & Physiology 1