Question 1

Which of the following best describes the function of the sinoatrial (SA) node in the heart?

Accepted Answer

It acts as the pacemaker, initiating impulses that set the heart rate.

Question 2

A patient presents with a heart block that prevents impulses from traveling from the atria to the ventricles. Which structure is most likely affected?

Accepted Answer

Atrioventricular (AV) bundle

Question 3

Which of the following equations correctly represents cardiac output (CO)?

Accepted Answer

$$CO = SV 	imes HR$$

Question 4

During which phase of the cardiac cycle do the ventricles contract while the atrioventricular (AV) valves are closed and the semilunar (SL) valves are not yet open?

Accepted Answer

Isovolumetric contraction

Question 5

Which of the following best explains why cardiac muscle cannot undergo tetanic contractions?

Accepted Answer

The refractory period in cardiac muscle is longer than the contraction period.

Question 6

A patient with hypertension is found to have an increased afterload. What is the most likely effect on stroke volume (SV)?

Accepted Answer

Stroke volume decreases due to increased resistance to ejection.

Question 7

Which of the following ions plays a major role in the plateau phase of the cardiac muscle action potential?

Accepted Answer

Calcium (Ca2+)

Question 8

Which of the following is a direct effect of sympathetic nervous system activation on the heart?

Accepted Answer

Increased heart rate and contractility

Question 9

A 60-year-old male presents with bradycardia (slow heart rate). Which of the following could be a contributing factor?

Accepted Answer

Increased parasympathetic (vagal) tone

Question 10

Which of the following best describes the Frank-Starling law of the heart?

Accepted Answer

The greater the stretch of cardiac muscle cells, the stronger the contraction.

Question 11

Which of the following would most likely result in a decreased heart rate?

Accepted Answer

Increased parasympathetic stimulation

Question 12

A patient is given a calcium channel blocker. What is the expected effect on cardiac contractility?

Accepted Answer

Decreased contractility

Question 13

Which of the following best describes the QRS complex on an electrocardiogram (ECG)?

Accepted Answer

Ventricular depolarization

Question 14

Which of the following is the correct formula for stroke volume (SV)?

Accepted Answer

$$SV = EDV - ESV$$

Question 15

A patient with hyperkalemia is at risk for which of the following cardiac complications?

Accepted Answer

Arrhythmias

Question 16

Which of the following best explains why the AV node delays the impulse from the atria to the ventricles?

Accepted Answer

To allow the atria to finish contracting and empty blood into the ventricles

Question 17

Which of the following would most likely increase cardiac output (CO)?

Accepted Answer

Increased stroke volume and heart rate

Question 18

A patient is experiencing a rapid heart rate due to increased thyroid hormone levels. Which of the following best explains this effect?

Accepted Answer

Thyroxine enhances the effects of norepinephrine and epinephrine.

Question 19

Which of the following is a benefit of the long absolute refractory period in cardiac muscle?

Accepted Answer

It prevents tetanic contractions, ensuring proper heart function.

Question 20

Which of the following best describes the effect of increased preload on stroke volume, according to the Frank-Starling law?

Accepted Answer

Increased preload increases stroke volume.

Chapter 17: The Cardiovascular System – The Heart (Study Notes)

Study Guide - Practice Questions

Study Guide - Flashcards