The cardiovascular system is made up of the heart, blood, and blood vessels. Its primary responsibility is to transport oxygenated blood and nutrients to the other organs and tissues within the body.

It also transports deoxygenated blood back to the lungs to pick up new oxygen molecules.

In this guide, we’ll take a closer look at the cardiovascular system and provide an overview of this topic. We included helpful practice questions for your benefit as well. So, if you’re ready, let’s get into it.

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What is the Cardiovascular System?

The cardiovascular system is the primary system that is responsible for circulating blood throughout the body. It consists of the following structures:

  • Heart
  • Blood vessels
  • Blood
  • Lymph
  • Lymphatic vessels

Each structure plays an important role in ensuring that the cardiovascular system functions properly.


The heart is a muscular organ with four chambers and is approximately the size of a fist. It is positioned in the middle compartment of the mediastinum of the chest, just behind the sternum.

The heart is the primary organ of the cardiovascular system and is what’s responsible for pumping blood throughout the body.

Heart illustration

Blood Vessels

Blood vessels are hollow tubes that carry blood to and from the heart throughout the body. The different types of blood vessels include arteries, veins, capillaries, and lymphatic vessels.


Blood plays a vital role in the cardiovascular system as it transports oxygen and nutrients to the different organs within the body. It also helps to transport carbon dioxide and other waste products for removal.

The main components of blood are red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes), and plasma.

Blood vessel illustration


Lymph is a clear, watery fluid that is found in the lymphatic system. It contains white blood cells, which help fight infections and diseases in the body.

Lymph also helps transport fat and other nutrients from the digestive system to the bloodstream.

Lymphatic Vessels

Lymphatic vessels are a network of thin tubes located throughout the body. They help transport lymph from the tissues to the bloodstream.

Cardiovascular System Practice Questions:

1. The cardiovascular system is responsible for what?
It is responsible for transporting metabolites to and from tissues; regulates blood flow mainly by altering the capacity of the vasculature and volume of blood it holds.

2. What is Afterload?
It is the load against which an activated muscle must try to shorten; greater afterloads result in lower velocities.

3. What are Baroreceptors?
They are pressure-sensitive nerve endings in the walls of the atria of the heart, the vena cava, the aortic arch, and the carotid sinus.

4. What is Cardiac Output?
The volume of blood pumped per minute by the heart.

5. What is Cardiac Tamponade?
Compression of the heart caused by the collection of blood, fluid, or gas under pressure in the pericardium.

6. What are Chemoreceptors?
Sensory nerve cells activated by changes in the chemical environment surrounding it; the chemoreceptors in the carotid artery are sensitive to PCO2 in the blood, signaling the respiratory center in the brain to increase or decrease ventilation.

7. What is congestive heart failure?
An abnormal condition that reflects impaired cardiac output, caused by MI, ischemic heart disease, or cardiomyopathy.

8. What is Contractility?
Property of muscle tissue to shorten in response to a stimulus, usually electrical.

9. What is End-diastolic volume (EDV)?
The volume of blood remaining in the ventricles just prior to contraction.

10. What is End-systolic volume (ESV)?
The volume of blood in the ventricles at the end of contraction (systole).

11. What is negative inotropism?
A decrease in contractility of the heart.

12. What is the pericardium?
The fibrous, serous sac that surrounds the heart and roots of the great vessels.

13. What is positive inotropism?
An increase in the contractility of the muscle tissue.

14. What is Preload?
The pressure stretching the ventricular walls at the onset of ventricular contraction.

15. What is Stenosis?
The narrowing of a valve or vessel.

16. What is Stroke Volume?
The volume of blood ejected by the left ventricle during each contraction.

17. What is vasoconstriction?
The narrowing of the blood vessels.

18. What is vasodilation?
The widening or distension of blood vessels, particularly arterioles, usually caused by nerve impulses or certain drugs that relax smooth muscle in the walls of the blood vessels.

19. What are the two major subdivisions of the vascular system?
The systemic vasculature and pulmonary vasculature.

20. What are the three major components of the systemic vasculature?
Arterial system, capillary system, and venous system.

21. What are the four mechanisms that aid in venous return to the heart?
(1) Sympathetic venous tone, (2) Skeletal muscle pumping, (3) Cardiac suction, and (4) Thoracic pressure differences caused by respiratory efforts.

22. What is an anatomic shunt?
Whenever venous blood mixes with arterial blood the overall oxygen count decreases.

23. The atrioventricular valves close during what?
It closes during systole (contraction of the ventricles), preventing backflow of blood into the atria. Closure of these valves provides a critical period of isovolumic contraction, during which chamber pressures quickly increase just before ejection of the blood.

24. What is the capillary system?
Microcirculation maintains a constant exchange of nutrients and waste products for the cells and tissues of the body.

25. What does CHF stand for?
Congestive heart failure.

26. What are some common valve problems?
Regurgitation and stenosis.

27. What is conductivity?
The ability of myocardial tissue to spread, or radiate electrical impulses.

28. What is contractility?
In response to an electrical impulse is the primary function of the myocardium.

29. What is the coronary sinus?
Passes left to right across the posterior surface of the heart. The coronary sinus empties into the right atrium between the opening of the inferior vena cava and the tricuspid valve.

30. What is the dicrotic notch?
Caused by elastic recoil of the arteries.

31. During cardiac contractions, what happen to blood?
It is ejected out of the heart and to the lungs through right valves and to the body through the left valves.

32. What is the Frank-Starling Law?
The more a cardiac fiber is stretched, the greater the tension it generates when contracted.

33. The heart is enclosed in a double-walled sac called what?
The pericardium.

34. What does HR stand for?
Heart Rate

35. Myocardial tissue possesses what four key properties?
Excitability, inherent rhythmicity, conductivity, and contractility.

36. What is regurgitation?
The backflow of blood through an incompetent or a damaged valve.

37. What is stenosis?
A pathologic narrowing or constriction of a valve outlet which causes increased pressure in the proximal chamber and vessels.

38. What are the thesbesian veins?
They empty directly into all the heart chambers — any blood coming through these veins that enter the left atrium or ventricle mixes with arterial blood coming from the lungs.

39. What is the valve between the right atrium and ventricle?
The tricuspid valve.

40. The valves of the heart are flaps of fibrous tissue firmly anchored to what?
Annulus fibrosus cordis, because they are located between the atria and ventricles. They are called atrioventricular valves.

41. What is vasoconstriction?
Constriction of the smooth muscles in peripheral blood vessels: causes blood pressure to increase even though blood volume is the same.

42. What is vasodilation?
Relaxation of the smooth muscles in arterioles and causes blood pressure to decrease even though blood volume has not changed.

43. What is the venous system?
Consists of small expandable venules and veins and larger more elastic veins.

44. Adrenergic stimulation and release of norepinephrine causes what?
It causes smooth muscle contraction and increased flow resistance.

45. Blood flow through large veins is affected by what?
It is affected by abdominal and intrathoracic pressure changes. 

46. What are the functions of blood?
To transport electrolytes, proteins, water, and hormones; contains platelets and clotting factors for hemostasis. It also transports respiratory gases to and from tissue, provides antibodies, carriers nutrients and waste products to cells.

47. What are conductance vessels?
Large Arteries in the arterial system. They have high elasticity and low resistance.

48. What are erythrocytes?
Red blood cells; they are generated in red blood marrow and they contain hemoglobin.

49. What is hematocrit?
The percentage of RBCs in the whole blood by volume. It is normally 3x the total amount of hemoglobin. The normal ranges include: Males 42-54%, Females 38-47%.

50. What is hemoglobin?
A molecule that allows the transport of oxygen.

51. What is plasma?
It is our body’s version of water and is approximately 90% of the blood volume. It has a yellow straw-like color.

52. What are the major cardiovascular effects of chemoreceptor stimulation?
They are vasoconstriction and increased heart rate.

53. Smooth muscle relaxation and dilation are the result of what?
Stimulation of either cholinergic or specialized beta-adrenergic receptors.

54. Stroke volume is affected by what three factors?
Preload, after load, and contractility.

55. What is the Thoracic Pump?
A mechanism that aids venous return.

56. To avoid organ/tissue damage and to maintain adequate perfusion pressures, the cardiovascular system balances what?
Relative volume and resistance.

57. What is the Aortic Valve?
A semilunar valve between the left ventricle and the aorta, prevents blood from flowing from the aorta back into the heart.

58. How is mean arterial pressure regulated?
By changes in cardiac output and systemic vascular resistance (SVR).

59. What is the Mitral Valve?
A valve in the heart that guards the opening between the left atrium and the left ventricle; prevents the blood in the ventricle from returning to the atrium. It’s alternative name is the bicuspid valve.

60. What is myocardial tissue?
It possesses four key properties: Excitability, Inherent rhythmicity, Conductivity, and Contractility.

61. What is the Pulmonic valve?
Divides the right ventricular outflow tract from the pulmonary artery. In normal conditions, the pulmonic valve prevents regurgitation of deoxygenated blood from the pulmonary artery back to the right ventricle. It is a semilunar valve with 3 cusps, and it is located anterior, superior, and slightly to the left of the aortic valve.

62. What is the Tricuspid valve?
A valve with three cusps and is situated between the right atrium and the right ventricle; allows blood to pass from atrium to ventricle and closes to prevent backflow when the ventricle contracts.

63. The underlying goal of the body’s cardiovascular control mechanisms is to what?
To ensure that all tissues receive what perfusion according to their metabolic needs.

64. What are the heart valves?
Pulmonic valve, aortic valve, mitral valve, and tricuspid valve.

65. What conducts impulses rapidly to ensure synchronous contraction of the ventricles?
Specialized myocardial tissues.

66. What factors determine cardiac stroke volume?
Preload, afterload, contractility, and heart rate.

67. What happens when chemoreceptors are stimulated?
Vasoconstriction and increased heart rate

68. Which heart chamber has the bulk of muscle mass?
The ventricles make up the bulk of muscle mass and do most of the pumping that circulates the blood.

69. Which part of the nervous system is responsible for the central control of the blood flow?
The sympathetic division of the autonomic nervous system.

70. What are the steps of blood flow through the heart?
Right atrium through the Tricuspid valve, to the Right ventricle through the Pulmonary valve to the Pulmonary arteries to the Lungs then to the Pulmonary veins to the Left atrium, through the Bicuspid/Mitral valve into the Left ventricle, through the Aortic valve to the Aorta to the body tissues.

71. What is the Aortic valve located?
Between the left ventricle and the aorta.

72. Where is the Bicuspid/mitral valve located?
Between left atrium and left ventricle.

73. What is Chordae tendonae?
Strong fibrous strings that attach cusps of AV valves to the heart wall.

74. What is the description of the average person’s heart?
It is a cone-shaped muscle that is about the size of your fist.

75. What is the physiological processes that can result from mitral stenosis?
The left atrium works harder than the left ventricle and blood begins to back up. More energy is expended with less positive results and the heart murmurs.

76. Describe the two atria?
The right atrium receives deoxygenated blood from body tissues. The left atrium receives oxygenated blood from the lungs.

77. Describe the two ventricles?
The right ventricle pumps blood to the lungs. The left ventricle pumps blood to the body tissues.

78. What is the Endocardium?
The inner layer of epithelium and connective tissue.

79. What is the Epicardium?
The outer covering of the heart.

80. What are the four chambers of the heart?
Left atrium, Left ventricle, Right atrium, Right ventricle.

81. What are the four valves found in the heart?
Bicuspid/mitral (AV), Tricuspid (AV), Aortic (semilunar), Pulmonary (semilunar).

82. What are the functions of all valves in the heart?
To keep blood flowing in one direction. To make the heart more efficient and use less energy.

83. What is the leading cause of death in the United States?
Cardiovascular Disease.

84. What is the myocardium?
The middle layer; composed of cardiac muscle tissue.

85. What is the pulmonary valve located?
Between the right ventricle and pulmonary trunk.

86. What is the purpose of the semilunar valves?
To assure that blood flows in one direction from the ventricles to the large arteries they connect to.

87. What is the purpose of the AV valves?
To assure that blood flows in one direction from the atrium to the ventricle.

88. What are the risk factors for cardiovascular disease?
Genetics, Hypertension (HTN), Elevated cholesterol, Diabetes, Obesity, Smoking, Inactivity, Gender (more prevalent in men).

89. What is Stenosis?
Narrowing of aperture (partial obstruction).

90. What are the three layers of the pericardium?
Fibrous, Parietal, and Visceral.

91. What are the three walls of the heart?
Epicardium, Myocardium, Endocardium.

92. Where is the tricuspid valve located?
Between the right atrium and right ventricle.

93. What are the two atrioventricular valves?
Bicuspid (or mitral) and Tricuspid.

94. What are the two semilunar valves?
The Aortic and Pulmonary.

95. What is the ultimate function of the cardiovascular system?
To ensure that all tissues are adequately perfused.

96. What borders the heart in the mediastinum?
Lungs, vertebrae, and sternum.

97. What is the difference between the visceral pericardium and the epicardium?

98. What is the first functional organ?
The heart.

99. What is the purpose of the fluid in the pericardial cavity?
To lubricate and reduce energy demands.

100. What separates the two atria?
The interatrial septum.

101. What separates the two ventricle?
The interventricular septum.

102. Where is the apex of the heart?
At the 5th intercostal space.

103. Where is the base of the heart?
At the 2nd rib.

104. Which are the pumping chambers?
The ventricles.

105. Which are the receiving chambers?
The atria.

Final Thoughts

The cardiovascular system is an important topic in the field of respiratory care because the heart works directly with the lungs to pump oxygenated blood throughout the body.

Otherwise, humans would not be able to survive.

If you enjoyed this information, we have a similar guide on the respiratory system that I think you’ll find helpful. Thanks for reading and, as always, breathe easy, my friend.

Medical Disclaimer: This content is for educational and informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Please consult with a physician with any questions that you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you read in this article. We strive for 100% accuracy, but errors may occur, and medications, protocols, and treatment methods may change over time.


The following are the sources that were used while doing research for this article:

  • Egan’s Fundamentals of Respiratory Care. 12th ed., Mosby, 2020 [Link]
  • Cardiopulmonary Anatomy & Physiology: Essentials of Respiratory Care. 7th ed., Cengage Learning, 2019 [Link]
  • Chaudhry, Raheel, et al. “Physiology, Cardiovascular.” National Library of Medicine, 14 Nov. 2021,
  • Moore, A., et al. “The Cardiovascular System.” National Library of Medicine, Sept. 2003,

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