NTA Cardiovascular Anatomy and Physiology 3

Question 1

Which electrolyte is most critical for maintaining the cardiac action potential and myocardial contractility?

Accepted Answer

Calcium

Answer

Sodium

Answer

Chloride

Answer

Magnesium

Question 2

The sympathetic nervous system affects the heart primarily by:

Accepted Answer

Increasing heart rate and contractility

Answer

Decreasing heart rate and contractility

Answer

Prolonging AV nodal conduction time

Answer

Reducing sinoatrial node automaticity

Question 3

What is the primary function of the Purkinje fibers?

Accepted Answer

Rapidly distribute the electrical impulse throughout the ventricles

Answer

Generate the initial impulse for each heartbeat

Answer

Delay conduction between atria and ventricles

Answer

Repolarize the atrial myocardium

Question 4

Hypokalemia (low potassium) is most likely to cause which ECG change?

Accepted Answer

Prominent U waves

Answer

Tall, peaked T waves

Answer

Shortened QT interval

Answer

Widened P waves

Question 5

Which vessel carries oxygenated blood from the lungs to the heart?

Accepted Answer

Pulmonary vein

Answer

Pulmonary artery

Answer

Superior vena cava

Answer

Aorta

Question 6

An increase in vagal (parasympathetic) tone will most directly result in:

Accepted Answer

Sinus bradycardia

Answer

Sinus tachycardia

Answer

Increased ventricular contractility

Answer

Shortened PR interval

Question 7

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

Accepted Answer

Pump blood against the higher resistance of the systemic circulation

Answer

Receive blood from both the pulmonary and systemic circuits

Answer

Initiate the cardiac action potential

Answer

Accommodate a larger blood volume per beat