Interpreting Electrocardiograms (ECGs)

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Which layer of the heart wall is also shared by the pericardial membrane?

Epicardium (correct)

Pericardium

Endocardium

Myocardium

What is the function of the pericardium?

To regulate the heart rate

To reduce friction between the heart and surrounding structures (correct)

To hold the heart in place

To provide nutrients to the heart

Where is the heart located within the thoracic cavity?

At the top of the thoracic cavity

To the left of the midline (correct)

To the right of the midline

At the bottom of the thoracic cavity

What is the size of the heart?

About the size of a fist Signup and view all the answers

What is the pericardial cavity filled with?

Pericardial fluid Signup and view all the answers

Which layer of the heart wall is composed of cardiac muscle?

Myocardium Signup and view all the answers

Which chamber of the heart receives blood from the superior and inferior vena cava and the coronary sinus?

Right atrium Signup and view all the answers

Which valve prevents blood flowing from the ventricles back into the atria?

Atrioventricular (AV) valve Signup and view all the answers

Which ventricle has thicker walls due to pumping blood throughout the body to locations where the resistance to blood flow is greater?

Left ventricle Signup and view all the answers

Which valve allows the ejection of blood from the heart into the arteries but prevents the back flow of blood into the ventricles?

Semilunar (SL) valve Signup and view all the answers

Which of the following factors determines stroke volume?

Preload Signup and view all the answers

According to the Frank-Starling law of the heart, what happens to the force of contraction during systole when there is a greater preload on cardiac muscle fibers?

It increases Signup and view all the answers

What does the Frank-Starling law of the heart state about the output of the right and left ventricles?

They are equal Signup and view all the answers

Which side of the heart is involved in systemic circulation?

Left side Signup and view all the answers

Which of the following factors influences heart rate?

Autonomic innervation Signup and view all the answers

What is the function of coronary circulation?

Delivers oxygenated blood and nutrients to the myocardium Signup and view all the answers

What is the body's principal mechanism of short-term control over cardiac output and blood pressure?

Changing heart rate Signup and view all the answers

What are the principal arteries branching from the ascending aorta that carry oxygenated blood?

Right and left coronary arteries Signup and view all the answers

What is the role of the atrioventricular (AV) node in the conducting system of the heart?

Slows down the cardiac action potential Signup and view all the answers

What happens when the components of the conduction system are disrupted?

Cardiac rhythm is restored with an artificial pacemaker Signup and view all the answers

Which of the following represents the conduction time from the beginning of atrial excitation to the beginning of ventricular excitation?

S-T segment Signup and view all the answers

What does the S-T segment represent in an electrocardiogram (ECG)?

Time when the ventricular contractile fibers are fully depolarized Signup and view all the answers

What is the first heart sound (lubb) created by?

Turbulence in blood flow caused by the closure of the atrioventricular valves Signup and view all the answers

What does the second heart sound (dupp) represent?

Closing of the semilunar valves Signup and view all the answers

What is cardiac output (CO)?

The volume of blood ejected from the left ventricle into the aorta each minute Signup and view all the answers