Q: If a patient has an end-diastolic volume (EDV) of 120 mL and an end-systolic volume (ESV) of 50 mL, what is their stroke volume?

$$SV = 120 - 50 = 70\ \text{mL}$$

Question 1

Which layer of the heart wall is primarily responsible for the heart's contractile function?

Accepted Answer

Myocardium

Question 2

A patient presents with chest pain and labored breathing after a viral infection. Imaging reveals fluid accumulation in the pericardial cavity. What is the most likely diagnosis?

Accepted Answer

Cardiac tamponade

Question 3

Which of the following best describes the function of the chordae tendineae in the heart?

Accepted Answer

They prevent atrioventricular valves from inverting during ventricular contraction.

Question 4

During which phase of the cardiac cycle are the aortic and pulmonary semilunar valves open?

Accepted Answer

Ventricular systole

Question 5

Which of the following equations correctly calculates cardiac output?

Accepted Answer

$$CO = HR 	imes SV$$

Question 6

A 25-year-old athlete has a maximal cardiac output of 35 L/min and a resting cardiac output of 5 L/min. What is his cardiac reserve?

Accepted Answer

$$35 \div 5 = 7$$

Question 7

Which of the following is the correct formula for stroke volume?

Accepted Answer

$$SV = EDV - ESV$$

Question 8

If a patient has an end-diastolic volume (EDV) of 120 mL and an end-systolic volume (ESV) of 50 mL, what is their stroke volume?

Accepted Answer

$$SV = 120 - 50 = 70\ 	ext{mL}$$

Question 9

Which of the following factors would most likely increase preload in the heart?

Accepted Answer

Increased venous return

Question 10

A patient with high blood pressure is found to have increased afterload. What effect does this have on stroke volume?

Accepted Answer

Stroke volume decreases

Question 11

Which ion's influx is primarily responsible for the plateau phase of the cardiac muscle action potential?

Accepted Answer

Ca2+

Question 12

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

Accepted Answer

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

Question 13

Which of the following is a consequence of myocardial infarction?

Accepted Answer

Replacement of dead cardiac muscle with scar tissue

Question 14

Which part of the conduction system is known as the heart's natural pacemaker?

Accepted Answer

Sinoatrial node

Question 15

A patient has damage to the SA node. Which structure can take over as the pacemaker, and what is the expected heart rate?

Accepted Answer

AV node; 40-50 beats/min

Question 16

Which wave on an electrocardiogram (ECG) represents ventricular repolarization?

Accepted Answer

T wave

Question 17

Which of the following would most likely decrease cardiac output?

Accepted Answer

Decreased venous return

Question 18

A patient is given a calcium channel blocker. What effect will this have on cardiac contractility?

Accepted Answer

Decrease contractility

Question 19

Which of the following is a direct effect of sympathetic stimulation on the heart?

Accepted Answer

Increased heart rate

Question 20

A patient with angina pectoris experiences chest pain during exertion. What is the underlying cause?

Accepted Answer

Temporary myocardial ischemia

Chapter 18 – The Heart: Structure, Function, and Physiology

Guida di studio - Domande di pratica

Study guide - Flashcard