Cardiovascular system – heart structure, cardiac cycle, ECG - One Line Questions

1. What is the average duration of the cardiac cycle in a resting adult? 0.8 seconds
2. What is the average heart rate for a healthy adult at rest? 60-100 beats per minute
3. During atrial systole, which valves are open? Mitral and tricuspid valves
4. During ventricular systole, which valves close? Mitral and tricuspid valves
5. During ventricular diastole, which valves open? Mitral and tricuspid valves
6. The first heart sound ('lub') is produced by the closure of which valves? Mitral and tricuspid valves
7. The second heart sound ('dub') is produced by the closure of which valves? Aortic and pulmonary valves
8. The QRS complex on an ECG represents: Ventricular depolarization
9. What does the T wave on an ECG represent? Ventricular repolarization
10. The PR interval on an ECG represents the time from the beginning of atrial depolarization to the beginning of: Ventricular depolarization
11. What is the term for the relaxation of the atria during the cardiac cycle? Atrial diastole
12. What is the term for the contraction of the ventricles during the cardiac cycle? Ventricular systole
13. Which part of the cardiac conduction system initiates the electrical impulse that triggers a heartbeat? Sinoatrial (SA) node
14. Elevation of the ST segment on an ECG is often indicative of: Myocardial infarction (heart attack)
15. The electrical impulse travels from the SA node to the AV node through the: Internodal pathways
16. The amount of blood ejected by the left ventricle with each beat is called: Stroke volume
17. Which of the following factors can increase stroke volume? Increased contractility
18. The sympathetic nervous system generally has what effect on heart rate? Increases heart rate
19. What is the contraction phase of the cardiac cycle called? Systole
20. What is the primary function of the cardiovascular system? Transport of oxygen, nutrients, and waste products
21. The muscular wall of the heart is called the: Myocardium
22. The sac that surrounds and protects the heart is known as the: Pericardium
23. An elevated afterload typically leads to: Decreased stroke volume
24. The parasympathetic nervous system, primarily via the vagus nerve, generally has what effect on heart rate? Decreases heart rate
25. The Q wave on an ECG represents: Initial depolarization of the ventricles
26. What are Purkinje fibers responsible for? Conducting electrical impulses to the ventricular myocardium
27. Which chamber of the heart receives deoxygenated blood from the body? Right atrium
28. The SA node is located in the wall of which chamber? Right atrium
29. An ECG measures the: Electrical activity of the heart
30. Which valve prevents the backflow of blood from the right ventricle to the right atrium? Tricuspid valve
31. Which valve controls the flow of blood from the left ventricle into the aorta? Aortic valve
32. The inner lining of the heart chambers and valves is made up of: Endocardium
33. What electrical event in the heart precedes atrial contraction? P wave
34. Which artery supplies oxygenated blood to the heart muscle itself? Coronary artery
35. The valve between the left atrium and the left ventricle is called the: Mitral valve
36. A prolonged PR interval on an ECG may indicate: AV block
37. Oxygenated blood returns from the lungs to which chamber of the heart? Left atrium
38. The pulmonary valve is located between the: Right ventricle and pulmonary artery
39. The AV node is located between which two chambers? Right atrium and right ventricle
40. The electrical impulse travels from the AV node to the ventricles via the: Bundle of His and Purkinje fibers
41. What is the term for the volume of blood pumped by the left ventricle per minute? Cardiac output
42. Cardiac output is calculated by multiplying: Stroke volume and heart rate
43. What is the relaxation phase of the cardiac cycle called? Diastole
44. What is afterload in the context of the cardiac cycle? The resistance the ventricle must overcome to eject blood
45. The ST segment on an ECG represents: The period between ventricular depolarization and repolarization
46. What is preload in the context of the cardiac cycle? The degree of stretch of the ventricular muscle before contraction
47. Which of the following is NOT a primary function of the myocardium? To generate heat
48. What is the primary role of the AV node in the cardiac conduction system? To delay the impulse before it reaches the ventricles
49. The P wave on an ECG represents: Atrial depolarization
50. The cardiac cycle begins with: Atrial systole