Q1. What is the muscular organ responsible for pumping blood throughout the circulatory system?
a) Lungs
b) Liver
c) Heart
d) Kidneys
Show Answer
Correct Answer: c) Heart
Explanation: The heart is a vital muscular organ that functions as the pump of the circulatory system. It receives blood from the body, pumps it to the lungs for oxygenation, then receives oxygen-rich blood from the lungs and pumps it back out to the body.
Q2. Which chamber of the heart receives deoxygenated blood from the body?
a) Left atrium
b) Right atrium
c) Left ventricle
d) Right ventricle
Show Answer
Correct Answer: b) Right atrium
Explanation: The right atrium receives deoxygenated blood from the body through the superior and inferior vena cavae. It then contracts to pump this blood into the right ventricle for pulmonary circulation.
Q3. What is the function of the valves in the heart?
a) To regulate blood pressure
b) To prevent backflow of blood
c) To produce red blood cells
d) To transport oxygen
Show Answer
Correct Answer: b) To prevent backflow of blood
Explanation: Valves in the heart ensure one-way blood flow by preventing the backward flow of blood. The atrioventricular valves (tricuspid and bicuspid/mitral) separate the atria from the ventricles, while the semilunar valves (pulmonary and aortic) prevent backflow into the ventricles after contraction.
Q4. Which blood vessels supply oxygenated blood to the heart muscle itself?
a) Coronary arteries
b) Pulmonary arteries
c) Pulmonary veins
d) Aorta
Show Answer
Correct Answer: a) Coronary arteries
Explanation: Coronary arteries are the blood vessels that supply oxygenated blood to the heart muscle (myocardium). They originate from the aorta and branch off to ensure adequate oxygenation and nutrient supply to the heart tissue.
Q5. During which phase of the cardiac cycle does the heart relax and fill with blood?
a) Systole
b) Diastole
c) Ventricular contraction
d) Atrial contraction
Show Answer
Correct Answer: b) Diastole
Explanation: Diastole is the phase of the cardiac cycle when the heart relaxes and fills with blood. During this phase, the atria and ventricles passively receive blood from the veins, and the coronary arteries fill with oxygenated blood to nourish the myocardium.
Q6. Which chamber of the heart pumps oxygenated blood to the rest of the body?
a) Right atrium
b) Right ventricle
c) Left atrium
d) Left ventricle
Show Answer
Correct Answer: d) Left ventricle
Explanation: The left ventricle receives oxygenated blood from the left atrium and pumps it out to the systemic circulation through the aorta. It has thicker muscular walls than the right ventricle to generate enough force to propel blood throughout the body.
Q7. What is the function of the septum in the heart?
a) To regulate heart rate
b) To prevent clot formation
c) To separate the left and right sides of the heart
d) To transport oxygen
Show Answer
Correct Answer: c) To separate the left and right sides of the heart
Explanation: The septum in the heart is a muscular wall that separates the left and right sides of the heart. It ensures that oxygen-rich blood (from the lungs) and oxygen-poor blood (from the body) do not mix, maintaining efficient circulation.
Q8. Which of the following is the correct sequence of chambers through which blood flows in the heart?
a) Left atrium, left ventricle, right atrium, right ventricle
b) Right atrium, right ventricle, left atrium, left ventricle
c) Left atrium, right atrium, left ventricle, right ventricle
d) Right atrium, left atrium, right ventricle, left ventricle
Show Answer
Correct Answer: b) Right atrium, right ventricle, left atrium, left ventricle
Explanation: Deoxygenated blood enters the right atrium, passes through the tricuspid valve into the right ventricle, then through the pulmonary valve into the pulmonary artery. Oxygenated blood returns to the left atrium via the pulmonary veins, passes through the bicuspid/mitral valve into the left ventricle, and is pumped out through the aortic valve into the aorta.
Q9. What causes the lub-dub sound of the heartbeat?
a) Contraction of the atria and ventricles
b) Opening and closing of the heart valves
c) Relaxation of the heart muscle
d) Blood flow through the coronary arteries
Show Answer
Correct Answer: b) Opening and closing of the heart valves
Explanation: The lub-dub sound of the heartbeat is caused by the closing of heart valves. The first sound (lub) is produced by the closing of the atrioventricular valves (tricuspid and bicuspid/mitral) during ventricular contraction, while the second sound (dub) is produced by the closing of the semilunar valves (pulmonary and aortic) during ventricular relaxation.
Q10. Which of the following statements about the heart is true?
a) The heart has four chambers: two atria and two ventricles
b) The right atrium receives oxygenated blood from the body
c) The heart pumps blood to the lungs for oxygenation
d) The septum separates the atria from the ventricles
Show Answer
Correct Answer: a) The heart has four chambers: two atria and two ventricles
Explanation: The human heart consists of four chambers: two atria (right atrium and left atrium) and two ventricles (right ventricle and left ventricle). The atria receive blood, while the ventricles pump blood out of the heart to the lungs and the rest of the body.
Q11. Which of the following is responsible for initiating and coordinating the heartbeat?
a) Aorta
b) Sinoatrial (SA) node
c) Coronary artery
d) Bundle of His
Show Answer
Correct Answer: b) Sinoatrial (SA) node
Explanation: The sinoatrial (SA) node, located in the right atrium, is known as the heart’s natural pacemaker. It generates electrical impulses that initiate and regulate the heartbeat by causing atrial contraction. These impulses are then conducted through the atria and stimulate the atrioventricular (AV) node.
Q12. What is the function of the atrioventricular (AV) node in the heart?
a) To regulate heart rate
b) To conduct electrical impulses from the atria to the ventricles
c) To contract the atria
d) To pump blood out of the heart
Show Answer
Correct Answer: b) To conduct electrical impulses from the atria to the ventricles
Explanation: The atrioventricular (AV) node is responsible for conducting electrical impulses from the atria to the ventricles. It delays the transmission of impulses to allow the atria to contract fully before ventricular contraction, ensuring efficient blood pumping.
Q13. Which of the following factors can influence heart rate?
a) Age
b) Blood pressure
c) Exercise
d) All of the above
Show Answer
Correct Answer: d) All of the above
Explanation: Heart rate can be influenced by various factors, including age, blood pressure, exercise, stress, hormones, and autonomic nervous system activity. For example, exercise generally increases heart rate to meet increased oxygen demand, while relaxation or sleep tends to lower heart rate.
Q14. Which of the following is NOT a major blood vessel connected to the heart?
a) Aorta
b) Pulmonary artery
c) Renal vein
d) Inferior vena cava
Show Answer
Correct Answer: c) Renal vein
Explanation: The renal vein is not directly connected to the heart but instead carries deoxygenated blood from the kidneys to the inferior vena cava, which then returns blood to the right atrium of the heart. The aorta, pulmonary artery, and inferior vena cava are major vessels directly connected to the heart.
Q15. What is the primary function of the heart valves?
a) To regulate blood pressure
b) To prevent backflow of blood
c) To produce red blood cells
d) To transport oxygen
Show Answer
Correct Answer: b) To prevent backflow of blood
Explanation: Heart valves ensure one-way blood flow by preventing the backward flow of blood. The atrioventricular valves (tricuspid and bicuspid/mitral) separate the atria from the ventricles, while the semilunar valves (pulmonary and aortic) prevent backflow into the ventricles after contraction.
Q16. Which of the following is the correct order of electrical conduction in the heart?
a) SA node → AV node → Bundle of His → Purkinje fibers
b) AV node → SA node → Bundle of His → Purkinje fibers
c) Bundle of His → SA node → AV node → Purkinje fibers
d) Purkinje fibers → Bundle of His → SA node → AV node
Show Answer
Correct Answer: a) SA node → AV node → Bundle of His → Purkinje fibers
Explanation: The electrical conduction in the heart begins with the sinoatrial (SA) node generating impulses, followed by the atrioventricular (AV) node, the bundle of His, and then the Purkinje fibers, which spread the impulses throughout the ventricles, leading to contraction.
Q17. Which blood vessel carries deoxygenated blood from the heart to the lungs?
a) Pulmonary artery
b) Pulmonary vein
c) Aorta
d) Superior vena cava
Show Answer
Correct Answer: a) Pulmonary artery
Explanation: The pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation. It is the only artery in the body that carries deoxygenated blood, whereas most arteries carry oxygenated blood away from the heart.
Q18. Which of the following structures separates the right and left sides of the heart?
a) Atrioventricular (AV) node
b) Aorta
c) Pulmonary artery
d) Septum
Show Answer
Correct Answer: d) Septum
Explanation: The septum in the heart is a muscular wall that separates the left and right sides of the heart. It ensures that oxygen-rich blood (from the lungs) and oxygen-poor blood (from the body) do not mix, maintaining efficient circulation.
Q19. What is the name of the artery that carries oxygenated blood away from the heart to the rest of the body?
a) Pulmonary artery
b) Pulmonary vein
c) Aorta
d) Superior vena cava
Show Answer
Correct Answer: c) Aorta
Explanation: The aorta is the largest artery in the human body and originates from the left ventricle of the heart. It carries oxygenated blood from the heart to various parts of the body, delivering nutrients and oxygen to tissues.
Q20. Which of the following conditions results from insufficient blood flow to the heart muscle?
a) Heart attack
b) Stroke
c) Hypertension
d) Arrhythmia
Show Answer
Correct Answer: a) Heart attack
Explanation: A heart attack, also known as myocardial infarction, occurs when there is a blockage in one or more of the coronary arteries, leading to insufficient blood flow (ischemia) to a part of the heart muscle. This lack of oxygen and nutrients can cause tissue damage or cell death in the affected area.
Q21. What is the term for the contraction phase of the cardiac cycle when the heart pumps blood?
a) Systole
b) Diastole
c) Arrhythmia
d) Ischemia
Show Answer
Correct Answer: a) Systole
Explanation: Systole is the contraction phase of the cardiac cycle during which the heart pumps blood. During ventricular systole, the ventricles contract, forcing blood into the pulmonary artery and aorta, while atrial systole refers to the contraction of the atria, pushing blood into the ventricles.
Q22. Which of the following statements about the heart’s electrical conduction system is true?
a) The SA node is located in the left atrium.
b) The Bundle of His is responsible for initiating the heartbeat.
c) The Purkinje fibers conduct electrical impulses to the atria.
d) The AV node is responsible for delaying impulses to allow atrial contraction before ventricular contraction.
Show Answer
Correct Answer: d) The AV node is responsible for delaying impulses to allow atrial contraction before ventricular contraction.
Explanation: The atrioventricular (AV) node is located between the atria and ventricles and is responsible for delaying electrical impulses before transmitting them to the ventricles. This delay ensures that the atria contract fully to push blood into the ventricles before ventricular contraction begins.
Q23. Which of the following factors can contribute to the development of heart disease?
a) Smoking
b) Sedentary lifestyle
c) Unhealthy diet
d) All of the above
Show Answer
Correct Answer: d) All of the above
Explanation: Smoking, a sedentary lifestyle, and an unhealthy diet are all risk factors that can contribute to the development of heart disease. These factors can lead to conditions such as hypertension, atherosclerosis, and obesity, increasing the likelihood of heart-related complications.
Q24. What is the term for the network of blood vessels that supplies oxygen and nutrients to the heart muscle?
a) Coronary circulation
b) Pulmonary circulation
c) Systemic circulation
d) Cardiac circulation
Show Answer
Correct Answer: a) Coronary circulation
Explanation: Coronary circulation refers to the network of blood vessels that supply oxygen and nutrients to the heart muscle (myocardium). Coronary arteries branch off from the aorta and encircle the heart, delivering oxygen-rich blood to ensure the heart’s metabolic needs are met.
Q25. Which of the following conditions is characterized by an irregular heartbeat rhythm?
a) Tachycardia
b) Bradycardia
c) Arrhythmia
d) Fibrillation
Show Answer
Correct Answer: c) Arrhythmia
Explanation: Arrhythmia refers to an irregular heartbeat rhythm, which may manifest as tachycardia (rapid heart rate), bradycardia (slow heart rate), or fibrillation (rapid and irregular contractions). Arrhythmias can be caused by various factors, including heart disease, electrolyte imbalances, and genetics.
Q26. What is the term for the thick, muscular layer of the heart responsible for its pumping action?
a) Endocardium
b) Epicardium
c) Myocardium
d) Pericardium
Show Answer
Correct Answer: c) Myocardium
Explanation: The myocardium is the thick, muscular middle layer of the heart wall responsible for the heart’s pumping action. It contracts rhythmically to propel blood through the chambers of the heart and into the blood vessels of the circulatory system.
Q27. Which of the following chambers of the heart receives oxygenated blood from the lungs?
a) Left atrium
b) Left ventricle
c) Right atrium
d) Right ventricle
Show Answer
Correct Answer: a) Left atrium
Explanation: Oxygenated blood returns to the heart from the lungs via the pulmonary veins, entering the left atrium. From the left atrium, blood flows into the left ventricle, which then pumps it out to the systemic circulation through the aorta.
Q28. What is the term for the outermost layer of the heart that protects and anchors it within the chest cavity?
a) Endocardium
b) Epicardium
c) Myocardium
d) Pericardium
Show Answer
Correct Answer: d) Pericardium
Explanation: The pericardium is the outermost layer of the heart composed of a fibrous sac that protects and anchors the heart within the chest cavity. It consists of two layers: the fibrous pericardium (outer layer) and the serous pericardium (inner layer).
Q29. Which of the following vessels carries oxygenated blood from the heart to the body tissues?
a) Pulmonary artery
b) Pulmonary vein
c) Aorta
d) Superior vena cava
Show Answer
Correct Answer: c) Aorta
Explanation: The aorta is the largest artery in the body and carries oxygenated blood from the left ventricle of the heart to various tissues and organs throughout the body. It branches into smaller arteries that deliver oxygen and nutrients to the systemic circulation.
Q30. Which of the following is a condition characterized by a narrowing of the coronary arteries, leading to reduced blood flow to the heart muscle?
a) Heart failure
b) Atherosclerosis
c) Angina pectoris
d) Cardiac arrest
Show Answer
Correct Answer: c) Angina pectoris
Explanation: Angina pectoris is a condition caused by reduced blood flow to the heart muscle due to coronary artery narrowing (atherosclerosis). It typically manifests as chest pain or discomfort, often triggered by physical exertion or stress, and is a common symptom of coronary artery disease.
Q31. What is the name of the large vein that returns deoxygenated blood from the upper body to the right atrium of the heart?
a) Aorta
b) Pulmonary artery
c) Superior vena cava
d) Inferior vena cava
Show Answer
Correct Answer: c) Superior vena cava
Explanation: The superior vena cava is a large vein that returns deoxygenated blood from the upper body, including the head, neck, and arms, to the right atrium of the heart. It plays a crucial role in venous return to the heart.
Q32. Which of the following chambers of the heart pumps deoxygenated blood to the lungs for oxygenation?
a) Left atrium
b) Left ventricle
c) Right atrium
d) Right ventricle
Show Answer
Correct Answer: d) Right ventricle
Explanation: The right ventricle pumps deoxygenated blood to the lungs for oxygenation. After receiving blood from the right atrium, the right ventricle contracts to propel blood through the pulmonary artery to the lungs.
Q33. Which of the following terms refers to the relaxation phase of the cardiac cycle when the heart fills with blood?
a) Systole
b) Diastole
c) Arrhythmia
d) Ischemia
Show Answer
Correct Answer: b) Diastole
Explanation: Diastole is the relaxation phase of the cardiac cycle when the heart fills with blood. During ventricular diastole, the ventricles relax, allowing blood to flow from the atria into the ventricles.
Q34. What is the term for the process by which the heart adjusts its rate and force of contraction to meet the body’s needs?
a) Cardiac output
b) Heart rate variability
c) Baroreflex
d) Autonomic regulation
Show Answer
Correct Answer: a) Cardiac output
Explanation: Cardiac output refers to the volume of blood pumped by the heart per unit of time and is determined by heart rate (beats per minute) and stroke volume (volume of blood pumped per heartbeat). The heart adjusts its rate and force of contraction to maintain adequate cardiac output to meet the body’s metabolic demands.
Q35. Which of the following structures in the heart is responsible for conducting electrical impulses from the atria to the ventricles?
a) Sinoatrial (SA) node
b) Atrioventricular (AV) node
c) Bundle of His
d) Purkinje fibers
Show Answer
Correct Answer: c) Bundle of His
Explanation: The Bundle of His, also known as the atrioventricular bundle, is responsible for conducting electrical impulses from the atria to the ventricles. It transmits the electrical signal from the atrioventricular (AV) node to the bundle branches, which then distribute the impulse to the Purkinje fibers and ventricles.
Q36. Which of the following conditions results from a blockage in one or more of the coronary arteries, leading to reduced blood flow to the heart muscle?
a) Heart failure
b) Atherosclerosis
c) Angina pectoris
d) Cardiac arrest
Show Answer
Correct Answer: c) Angina pectoris
Explanation: Angina pectoris is a condition characterized by chest pain or discomfort caused by reduced blood flow to the heart muscle due to coronary artery narrowing (atherosclerosis). It typically occurs during physical exertion or stress when the heart’s oxygen demand exceeds supply and is relieved with rest or medication.
Q37. Which of the following vessels carries deoxygenated blood from the heart to the lungs for oxygenation?
a) Pulmonary artery
b) Pulmonary vein
c) Aorta
d) Inferior vena cava
Show Answer
Correct Answer: a) Pulmonary artery
Explanation: The pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation. It is the only artery in the body that carries deoxygenated blood, whereas most arteries carry oxygenated blood away from the heart.
Q38. Which of the following structures is located between the left atrium and left ventricle of the heart and prevents backflow of blood into the atrium during ventricular contraction?
a) Tricuspid valve
b) Bicuspid valve (mitral valve)
c) Pulmonary valve
d) Aortic valve
Show Answer
Correct Answer: b) Bicuspid valve (mitral valve)
Explanation: The bicuspid valve, also known as the mitral valve, is located between the left atrium and left ventricle of the heart. It consists of two cusps and prevents backflow of blood into the atrium during ventricular contraction, ensuring one-way flow of blood from the atria to the ventricles.
Q39. What is the term for the volume of blood pumped by the heart per minute?
a) Stroke volume
b) Cardiac output
c) Heart rate
d) Venous return
Show Answer
Correct Answer: b) Cardiac output
Explanation: Cardiac output refers to the volume of blood pumped by the heart per unit of time, usually measured in milliliters per minute. It is determined by multiplying heart rate (the number of heartbeats per minute) by stroke volume (the volume of blood pumped per heartbeat).
Q40. Which of the following structures is responsible for coordinating the contraction of the heart chambers and ensuring efficient blood pumping?
a) Sinoatrial (SA) node
b) Atrioventricular (AV) node
c) Bundle of His
d) Purkinje fibers
Show Answer
Correct Answer: d) Purkinje fibers
Explanation: Purkinje fibers are specialized cardiac muscle fibers responsible for coordinating the contraction of the heart chambers and ensuring efficient blood pumping. They distribute electrical impulses rapidly throughout the ventricles, leading to synchronized ventricular contraction and ejection of blood into the pulmonary and systemic circulations.
Q41. Which of the following conditions results from an abnormal heart rhythm characterized by rapid and irregular contractions of the atria?
a) Atrial fibrillation
b) Ventricular tachycardia
c) Bradycardia
d) Atrial flutter
Show Answer
Correct Answer: a) Atrial fibrillation
Explanation: Atrial fibrillation is an abnormal heart rhythm characterized by rapid and irregular contractions of the atria. This can lead to inefficient blood pumping and an increased risk of stroke or heart failure if left untreated.
Q42. Which of the following factors contributes to the development of atherosclerosis, a condition involving the buildup of plaque in the arteries?
a) High cholesterol levels
b) Hypertension
c) Smoking
d) All of the above
Show Answer
Correct Answer: d) All of the above
Explanation: Atherosclerosis, a condition characterized by the buildup of plaque in the arteries, can be caused by various factors, including high cholesterol levels, hypertension, smoking, diabetes, and obesity. These factors promote the accumulation of fatty deposits in the arterial walls, leading to narrowing and hardening of the arteries.
Q43. Which of the following blood vessels carries oxygenated blood from the lungs to the heart?
a) Pulmonary artery
b) Pulmonary vein
c) Aorta
d) Inferior vena cava
Show Answer
Correct Answer: b) Pulmonary vein
Explanation: Pulmonary veins carry oxygenated blood from the lungs to the heart, specifically to the left atrium. Unlike most veins, which carry deoxygenated blood, pulmonary veins transport oxygenated blood back to the heart from the lungs.
Q44. What is the term for the minimum pressure exerted by the blood against the walls of the arteries when the heart is at rest?
a) Systolic pressure
b) Diastolic pressure
c) Pulse pressure
d) Mean arterial pressure
Show Answer
Correct Answer: b) Diastolic pressure
Explanation: Diastolic pressure is the minimum pressure exerted by the blood against the walls of the arteries during the relaxation phase of the cardiac cycle (diastole), when the heart is at rest. It represents the pressure in the arteries between heartbeats.
Q45. Which of the following chambers of the heart receives deoxygenated blood from the body?
a) Left atrium
b) Right atrium
c) Left ventricle
d) Right ventricle
Show Answer
Correct Answer: b) Right atrium
Explanation: The right atrium receives deoxygenated blood from the body through the superior and inferior vena cavae. It then contracts to pump this blood into the right ventricle for pulmonary circulation.
Q46. What is the term for the medical procedure used to open narrowed or blocked coronary arteries to restore blood flow to the heart muscle?
a) Coronary artery bypass grafting (CABG)
b) Coronary angioplasty
c) Stent placement
d) Valve replacement surgery
Show Answer
Correct Answer: b) Coronary angioplasty
Explanation: Coronary angioplasty, also known as percutaneous coronary intervention (PCI), is a medical procedure used to open narrowed or blocked coronary arteries. A balloon-tipped catheter is inserted into the artery and inflated to widen the narrowed segment, often followed by the placement of a stent to keep the artery open.
Q47. Which of the following statements about the heart’s electrical conduction system is true?
a) The SA node is located in the left ventricle.
b) The AV node is responsible for initiating the heartbeat.
c) The Bundle of His conducts electrical impulses to the atria.
d) The Purkinje fibers distribute impulses throughout the atria.
Show Answer
Correct Answer: c) The Bundle of His conducts electrical impulses to the atria.
Explanation: The Bundle of His, also known as the atrioventricular bundle, conducts electrical impulses from the atrioventricular (AV) node to the ventricles, rather than to the atria. It plays a crucial role in transmitting signals for ventricular contraction.
Q48. What is the name of the condition characterized by chest pain or discomfort caused by reduced blood flow to the heart muscle?
a) Myocardial infarction
b) Atrial fibrillation
c) Heart failure
d) Angina pectoris
Show Answer
Correct Answer: d) Angina pectoris
Explanation: Angina pectoris is a condition characterized by chest pain or discomfort caused by reduced blood flow to the heart muscle (myocardium), usually due to coronary artery disease. It typically occurs during physical exertion or stress and is relieved with rest or medication.
Q49. Which of the following structures is responsible for coordinating the contraction of the atria and ventricles to ensure efficient blood pumping?
a) Sinoatrial (SA) node
b) Atrioventricular (AV) node
c) Bundle of His
d) Purkinje fibers
Show Answer
Correct Answer: c) Bundle of His
Explanation: The Bundle of His, also known as the atrioventricular bundle, is responsible for coordinating the contraction of the atria and ventricles to ensure efficient blood pumping. It conducts electrical impulses from the atrioventricular (AV) node to the bundle branches, which then distribute the impulses to the Purkinje fibers and ventricles.
Q50. What is the term for the volume of blood pumped out by a ventricle with each heartbeat?
a) Cardiac output
b) Stroke volume
c) Heart rate
d) Venous return
Show Answer
Correct Answer: b) Stroke volume
Explanation: Stroke volume refers to the volume of blood pumped out by a ventricle with each heartbeat. It is determined by factors such as preload (volume of blood in the ventricles before contraction), afterload (resistance against which the heart must pump), and myocardial contractility.