Here below some basic MCQ’s about “Body fluid and circulation” with answer which is explained in details. Let’s check one by one which is given below.
MCQ 1:
Which of the following is the primary component of blood?
A) Plasma
B) White blood cells
C) Platelets
D) Red blood cells
Answer: A) Plasma
Explanation: Plasma makes up about 55% of blood volume and is primarily composed of water, electrolytes, proteins, and other substances. While red blood cells, white blood cells, and platelets are important, they are present in smaller proportions compared to plasma.
MCQ 2:
What is the role of hemoglobin in the blood?
A) Clotting
B) Oxygen transport
C) Immune response
D) Nutrient transport
Answer: B) Oxygen transport
Explanation: Hemoglobin is a protein in red blood cells that binds to oxygen in the lungs and carries it to tissues throughout the body. While it plays a minor role in carbon dioxide transport, its primary function is oxygen transport.
MCQ 3:
Which type of blood vessel carries oxygenated blood away from the heart?
A) Veins
B) Arteries
C) Capillaries
D) Lymphatic vessels
Answer: B) Arteries
Explanation: Arteries carry oxygenated blood away from the heart to the body (with the exception of the pulmonary arteries, which carry deoxygenated blood to the lungs). Veins carry deoxygenated blood back to the heart.
MCQ 4:
The cardiac cycle includes which of the following phases?
A) Systole and diastole
B) Inspiration and expiration
C) Contraction and relaxation
D) A and C
Answer: D) A and C
Explanation: The cardiac cycle consists of systole (the contraction phase) and diastole (the relaxation phase). Together, these phases allow for the pumping of blood through the heart and circulation.
MCQ 5:
Which hormone is primarily responsible for regulating blood pressure?
A) Insulin
B) Adrenaline
C) Aldosterone
D) Estrogen
Answer: C) Aldosterone
Explanation: Aldosterone is a hormone produced by the adrenal glands that helps regulate blood pressure by increasing sodium and water reabsorption in the kidneys, thereby increasing blood volume. Adrenaline can affect heart rate but is not the primary regulator of blood pressure.
MCQ 6:
Which of the following is the largest component of blood?
A) Red blood cells
B) White blood cells
C) Plasma
D) Platelets
Answer: C) Plasma
Explanation: Plasma constitutes about 55% of blood volume, making it the largest component, while red blood cells, white blood cells, and platelets make up the remaining 45%.
MCQ 7:
What is the main function of platelets?
A) Oxygen transport
B) Blood clotting
C) Immune response
D) Nutrient transport
Answer: B) Blood clotting
Explanation: Platelets are small cell fragments that play a crucial role in hemostasis, the process of blood clotting, preventing excessive bleeding when injuries occur.
MCQ 8:
What component of blood is responsible for transporting carbon dioxide?
A) Hemoglobin
B) Plasma
C) White blood cells
D) Fibrinogen
Answer: A) Hemoglobin
Explanation: Hemoglobin can bind to carbon dioxide as well as oxygen, transporting CO2 from tissues back to the lungs for exhalation.
MCQ 9:
Which part of the heart receives deoxygenated blood from the body?
A) Left atrium
B) Right atrium
C) Left ventricle
D) Right ventricle
Answer: B) Right atrium
Explanation: The right atrium receives deoxygenated blood from the body via the superior and inferior vena cavae.
MCQ 10:
The heart is divided into how many chambers?
A) Two
B) Three
C) Four
D) Five
Answer: C) Four
Explanation: The human heart has four chambers: two atria (left and right) and two ventricles (left and right).
MCQ 11:
What is the role of the sinoatrial (SA) node?
A) It pumps blood.
B) It generates electrical impulses.
C) It prevents backflow of blood.
D) It regulates blood pressure.
Answer: B) It generates electrical impulses.
Explanation: The SA node, located in the right atrium, is known as the natural pacemaker of the heart, initiating the electrical impulses that stimulate heartbeats.
MCQ 12:
Which blood type is considered the universal donor?
A) A
B) B
C) AB
D) O
Answer: D) O
Explanation: Blood type O negative is considered the universal donor because it has no A or B antigens on its red blood cells, making it compatible with all blood types in emergencies.
MCQ 13:
What is the normal range of blood pressure in adults?
A) 90/60 mmHg
B) 120/80 mmHg
C) 140/90 mmHg
D) 160/100 mmHg
Answer: B) 120/80 mmHg
Explanation: A normal blood pressure reading for adults is typically around 120/80 mmHg, known as the “gold standard.”
MCQ 14:
Which part of the circulatory system carries blood from the heart to the lungs?
A) Aorta
B) Pulmonary arteries
C) Veins
D) Coronary arteries
Answer: B) Pulmonary arteries
Explanation: The pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs for oxygenation.
MCQ 15:
Which of the following is NOT a function of the circulatory system?
A) Transport of nutrients
B) Regulation of body temperature
C) Production of hormones
D) Removal of waste products
Answer: C) Production of hormones
Explanation: While the circulatory system transports hormones produced by endocrine glands, it does not produce hormones itself.
MCQ 16:
What is the role of the valves in the heart?
A) Preventing blood pressure
B) Allowing blood flow in one direction
C) Generating electrical impulses
D) Increasing heart rate
Answer: B) Allowing blood flow in one direction
Explanation: Heart valves ensure that blood flows in one direction through the heart and prevent backflow during contractions.
MCQ 17:
What is the primary function of the lymphatic system?
A) Oxygen transport
B) Nutrient absorption
C) Immune defense
D) Blood clotting
Answer: C) Immune defense
Explanation: The lymphatic system is essential for immune function, helping to defend against pathogens and maintain fluid balance in the body.
MCQ 18:
Which of the following is the smallest type of blood vessel?
A) Arteries
B) Veins
C) Capillaries
D) Aneurysms
Answer: C) Capillaries
Explanation: Capillaries are the smallest blood vessels and are responsible for the exchange of gases, nutrients, and waste between blood and tissues.
MCQ 19:
What is the function of the pulmonary circulation?
A) Carry oxygenated blood to the body
B) Carry deoxygenated blood to the lungs
C) Regulate body temperature
D) Supply blood to the heart muscle
Answer: B) Carry deoxygenated blood to the lungs
Explanation: Pulmonary circulation is the pathway in which deoxygenated blood is transported from the right side of the heart to the lungs for oxygenation.
MCQ 20:
What initiates the contraction of the heart?
A) Atrial contraction
B) Ventricular contraction
C) SA node
D) AV node
Answer: C) SA node
Explanation: The SA node generates electrical impulses that trigger heart contractions, starting with the atria.
MCQ 21:
What is the average volume of blood in an adult human body?
A) 2-4 liters
B) 4-6 liters
C) 6-8 liters
D) 8-10 liters
Answer: B) 4-6 liters
Explanation: The average adult has approximately 4-6 liters of blood in their body, depending on size and gender.
MCQ 22:
Which type of white blood cell is primarily responsible for fighting viral infections?
A) Neutrophils
B) Lymphocytes
C) Eosinophils
D) Basophils
Answer: B) Lymphocytes
Explanation: Lymphocytes, particularly T cells and B cells, play a crucial role in the immune response against viral infections.
MCQ 23:
Which of the following is a function of the kidneys related to blood?
A) Oxygen transport
B) Hormone production
C) Blood filtration
D) Nutrient absorption
Answer: C) Blood filtration
Explanation: The kidneys filter waste products and excess substances from the blood, playing a vital role in maintaining homeostasis.
MCQ 24:
What is the primary gas exchanged in the alveoli of the lungs?
A) Oxygen
B) Carbon dioxide
C) Nitrogen
D) Hydrogen
Answer: A) Oxygen
Explanation: The primary function of alveoli is to facilitate the exchange of oxygen from the air into the blood and carbon dioxide from the blood into the air.
MCQ 25:
Which blood vessel has the thickest walls?
A) Capillaries
B) Veins
C) Arteries
D) Lymphatic vessels
Answer: C) Arteries
Explanation: Arteries have thicker walls than veins to withstand the higher pressure of blood being pumped from the heart.
MCQ 26:
What is the function of fibrinogen in blood?
A) Oxygen transport
B) Blood clotting
C) Nutrient transport
D) Immune response
Answer: B) Blood clotting
Explanation: Fibrinogen is a protein in blood plasma that is converted into fibrin during the clotting process, helping to form blood clots.
MCQ 27:
Which of the following components is NOT found in plasma?
A) Proteins
B) Electrolytes
C) Red blood cells
D) Nutrients
Answer: C) Red blood cells
Explanation: Red blood cells are suspended in plasma but are not a component of plasma itself, which consists mainly of water, proteins, electrolytes, and nutrients.
MCQ 28:
Which type of blood vessel carries deoxygenated blood from the tissues back to the heart?
A) Arteries
B) Capillaries
C) Veins
D) Lymphatic vessels
Answer: C) Veins
Explanation: Veins are responsible for returning deoxygenated blood to the heart from the body’s tissues.
MCQ 29:
What is the average heart rate of a resting adult?
A) 40-60 bpm
B) 60-100 bpm
C) 100-120 bpm
D) 120-140 bpm
Answer: B) 60-100 bpm
Explanation: The average resting heart rate for adults typically falls within the range of 60 to 100 beats per minute.
MCQ 30:
What is the main function of the aorta?
A) Pump blood
B) Carry deoxygenated blood
C) Distribute oxygenated blood to the body
D) Filter blood
Answer: C) Distribute oxygenated blood to the body
Explanation: The aorta is the largest artery in the body and carries oxygenated blood away from the heart to supply the rest of the body.
MCQ 31:
Which type of blood cell is primarily involved in immune responses?
A) Erythrocytes
B) Thrombocytes
C) Leukocytes
D) Plasma cells
Answer: C) Leukocytes
Explanation: Leukocytes, or white blood cells, are critical for the immune system, helping to defend against infections and foreign substances.
MCQ 32:
What is the main purpose of the circulatory system?
A) Digestion
B) Respiration
C) Transportation of substances
D) Excretion
Answer: C) Transportation of substances
Explanation: The circulatory system’s primary function is to transport oxygen, nutrients, hormones, and waste products throughout the body.
MCQ 33:
Which of the following is a characteristic of veins?
A) Thick muscular walls
B) Valves to prevent backflow
C) High-pressure blood flow
D) Carry oxygenated blood only
Answer: B) Valves to prevent backflow
Explanation: Veins have valves that prevent the backflow of blood as it returns to the heart, especially from the lower extremities.
MCQ 34:
What is the term for the liquid part of the blood?
A) Serum
B) Plasma
C) Hemoglobin
D) Cytoplasm
Answer: B) Plasma
Explanation: Plasma is the liquid component of blood, in which cells, nutrients, hormones, and waste products are suspended.
MCQ 35:
Which condition is characterized by high blood pressure?
A) Hypotension
B) Hypertension
C) Arrhythmia
D) Anemia
Answer: B) Hypertension
Explanation: Hypertension is a condition in which blood pressure is consistently elevated, which can lead to health problems if untreated.
MCQ 36:
What is the primary role of red blood cells?
A) Immune defense
B) Nutrient transport
C) Oxygen transport
D) Blood clotting
Answer: C) Oxygen transport
Explanation: Red blood cells are specialized for transporting oxygen from the lungs to the body’s tissues and returning carbon dioxide to the lungs.
MCQ 37:
What type of circulation supplies blood to the heart muscle itself?
A) Systemic circulation
B) Pulmonary circulation
C) Coronary circulation
D) Lymphatic circulation
Answer: C) Coronary circulation
Explanation: Coronary circulation refers to the flow of blood to and from the tissues of the heart muscle, ensuring it receives the oxygen and nutrients it needs.
MCQ 38:
What is the role of the atrioventricular (AV) node in the heart?
A) To generate impulses
B) To delay impulses between atria and ventricles
C) To pump blood
D) To regulate blood pressure
Answer: B) To delay impulses between atria and ventricles
Explanation: The AV node acts as a gatekeeper, delaying electrical impulses from the atria before they pass to the ventricles, allowing the atria to fully contract before the ventricles.
MCQ 39:
Which electrolyte is crucial for muscle contraction and nerve function?
A) Calcium
B) Sodium
C) Potassium
D) Magnesium
Answer: A) Calcium
Explanation: Calcium is essential for muscle contraction and plays a vital role in transmitting nerve impulses, as well as in various cellular processes.
MCQ 40:
What is the process of blood cell production called?
A) Hemostasis
B) Hematopoiesis
C) Hemolysis
D) Homeostasis
Answer: B) Hematopoiesis
Explanation: Hematopoiesis is the process by which blood cells are produced in the bone marrow, including red blood cells, white blood cells, and platelets.
MCQ 41:
What is the primary function of the vena cava?
A) Carry oxygenated blood to the heart
B) Carry deoxygenated blood to the heart
C) Supply blood to the lungs
D) Pump blood to the body
Answer: B) Carry deoxygenated blood to the heart
Explanation: The superior and inferior vena cavae are large veins that carry deoxygenated blood from the body back to the right atrium of the heart.
MCQ 42:
What is the primary component of lymph?
A) Red blood cells
B) Plasma
C) White blood cells
D) Tissue fluid
Answer: D) Tissue fluid
Explanation: Lymph is primarily composed of tissue fluid that has leaked from blood vessels, along with white blood cells that help in immune function.
MCQ 43:
Which of the following is true regarding capillaries?
A) They have thick walls to handle high pressure.
B) They allow exchange of substances between blood and tissues.
C) They only carry oxygenated blood.
D) They are larger than arteries.
Answer: B) They allow exchange of substances between blood and tissues.
Explanation: Capillaries have thin walls that facilitate the exchange of oxygen, carbon dioxide, nutrients, and waste products between the blood and surrounding tissues.
MCQ 44:
Which blood component is essential for transporting oxygen?
A) Plasma
B) Leukocytes
C) Erythrocytes
D) Thrombocytes
Answer: C) Erythrocytes
Explanation: Erythrocytes, or red blood cells, are specialized to transport oxygen throughout the body using hemoglobin.
MCQ 45:
What is the main function of the circulatory system’s valves?
A) Increase blood pressure
B) Prevent blood from flowing backward
C) Pump blood to the lungs
D) Exchange gases
Answer: B) Prevent blood from flowing backward
Explanation: The valves in the heart and veins ensure that blood flows in one direction, preventing backflow and maintaining efficient circulation.
MCQ 46:
What is the term for the contraction of the heart?
A) Diastole
B) Systole
C) Arrhythmia
D) Hemostasis
Answer: B) Systole
Explanation: Systole refers to the phase of the cardiac cycle during which the heart muscle contracts and pumps blood out of the chambers.
MCQ 47:
Which vitamin is essential for the synthesis of clotting factors in the liver?
A) Vitamin A
B) Vitamin B12
C) Vitamin K
D) Vitamin D
Answer: C) Vitamin K
Explanation: Vitamin K is crucial for the synthesis of several proteins that mediate blood coagulation (clotting).
MCQ 48:
What happens during diastole?
A) The heart relaxes and fills with blood.
B) The heart contracts and pumps blood.
C) Blood pressure decreases significantly.
D) Oxygen is absorbed in the lungs.
Answer: A) The heart relaxes and fills with blood.
Explanation: Diastole is the phase of the cardiac cycle when the heart muscle relaxes and the chambers fill with blood.
MCQ 49:
Which type of blood vessel has the highest pressure?
A) Capillaries
B) Veins
C) Arteries
D) Venules
Answer: C) Arteries
Explanation: Arteries carry blood away from the heart under high pressure generated by heart contractions, especially the aorta.
MCQ 50:
What is the main role of the spleen in the circulatory system?
A) Producing insulin
B) Filtering blood and recycling iron
C) Pumping blood
D) Regulating blood pressure
Answer: B) Filtering blood and recycling iron
Explanation: The spleen filters blood, removing old or damaged red blood cells and recycling iron for future use in hemoglobin production.
MCQ 51:
Which structure prevents backflow of blood in the heart?
A) Septum
B) Valves
C) Chordae tendineae
D) Myocardium
Answer: B) Valves
Explanation: Heart valves, located between the atria and ventricles as well as at the exits of the ventricles, prevent backflow of blood during contractions.
MCQ 52:
What is the main purpose of red blood cell shape?
A) Flexibility to navigate through capillaries
B) Increase oxygen binding capacity
C) Decrease cell size
D) Facilitate immune function
Answer: A) Flexibility to navigate through capillaries
Explanation: The biconcave shape of red blood cells provides flexibility, allowing them to squeeze through narrow capillaries while maximizing surface area for gas exchange.
MCQ 53:
Which component of blood is involved in the immune response?
A) Plasma
B) Erythrocytes
C) Thrombocytes
D) Leukocytes
Answer: D) Leukocytes
Explanation: Leukocytes, or white blood cells, are key players in the immune system, defending the body against infections and foreign invaders.
MCQ 54:
What is the role of the intercalated discs in cardiac muscle?
A) Prevent backflow
B) Facilitate electrical impulses
C) Support blood vessel growth
D) Store calcium ions
Answer: B) Facilitate electrical impulses
Explanation: Intercalated discs are specialized connections between cardiac muscle cells that allow for rapid transmission of electrical impulses, ensuring coordinated heart contractions.
MCQ 55:
Which condition is characterized by low red blood cell count?
A) Leukemia
B) Anemia
C) Thrombocytopenia
D) Hemophilia
Answer: B) Anemia
Explanation: Anemia is a condition marked by a deficiency in the number or quality of red blood cells, leading to reduced oxygen delivery to tissues.
MCQ 56:
What is the role of the aortic valve?
A) Prevent backflow from the aorta to the left ventricle
B) Allow blood to flow from the left atrium to the left ventricle
C) Prevent backflow from the pulmonary artery
D) Regulate blood flow to the coronary arteries
Answer: A) Prevent backflow from the aorta to the left ventricle
Explanation: The aortic valve prevents the backflow of blood from the aorta into the left ventricle after contraction.
MCQ 57:
Which of the following vessels has valves?
A) Arteries
B) Capillaries
C) Veins
D) All of the above
Answer: C) Veins
Explanation: Valves are present in veins to prevent backflow of blood, particularly in the limbs where blood must travel against gravity.
MCQ 58:
What is the role of the coronary arteries?
A) Supply blood to the lungs
B) Supply blood to the heart muscle
C) Carry deoxygenated blood to the heart
D) Filter blood in the spleen
Answer: B) Supply blood to the heart muscle
Explanation: Coronary arteries branch off from the aorta and supply oxygenated blood to the heart muscle itself.
MCQ 59:
What term describes the volume of blood pumped by the heart per minute?
A) Stroke volume
B) Cardiac output
C) Blood pressure
D) Heart rate
Answer: B) Cardiac output
Explanation: Cardiac output is the volume of blood that the heart pumps in one minute, calculated as heart rate multiplied by stroke volume.
MCQ 60:
Which blood vessel is responsible for nutrient and gas exchange?
A) Artery
B) Vein
C) Capillary
D) Lymphatic vessel
Answer: C) Capillary
Explanation: Capillaries are the sites of exchange of oxygen, carbon dioxide, nutrients, and waste products between blood and tissues.
MCQ 61:
What is the primary function of the lungs in the circulatory system?
A) Pumping blood
B) Gas exchange
C) Filtering blood
D) Storing blood
Answer: B) Gas exchange
Explanation: The lungs are responsible for the exchange of gases (oxygen and carbon dioxide) between the air and the bloodstream.
MCQ 62:
What is the primary role of the immune system?
A) Transport nutrients
B) Regulate body temperature
C) Defend against pathogens
D) Remove waste products
Answer: C) Defend against pathogens
Explanation: The immune system protects the body from infections and diseases by identifying and destroying pathogens.
MCQ 63:
Which part of the brain regulates heart rate?
A) Cerebrum
B) Medulla oblongata
C) Cerebellum
D) Thalamus
Answer: B) Medulla oblongata
Explanation: The medulla oblongata regulates vital functions, including heart rate and blood pressure, as part of the autonomic nervous system.
MCQ 64:
What is the function of the carotid arteries?
A) Supply blood to the heart
B) Supply blood to the brain
C) Carry deoxygenated blood
D) Regulate blood pressure
Answer: B) Supply blood to the brain
Explanation: The carotid arteries carry oxygenated blood from the heart to the brain, supplying essential nutrients and oxygen.
MCQ 65:
Which condition results from a blockage in the coronary arteries?
A) Stroke
B) Heart attack
C) Hypertension
D) Anemia
Answer: B) Heart attack
Explanation: A blockage in the coronary arteries can restrict blood flow to the heart muscle, leading to a heart attack (myocardial infarction).
MCQ 66:
What is the primary function of the lymphatic system?
A) Nutrient transport
B) Fluid balance and immune response
C) Blood clotting
D) Oxygen transport
Answer: B) Fluid balance and immune response
Explanation: The lymphatic system maintains fluid balance by collecting excess tissue fluid and plays a key role in the immune response.
MCQ 67:
Which organ is primarily responsible for filtering blood?
A) Liver
B) Heart
C) Kidneys
D) Spleen
Answer: C) Kidneys
Explanation: The kidneys filter waste products and excess substances from the blood, producing urine for excretion.
MCQ 68:
What is the effect of adrenaline on the heart?
A) Decrease heart rate
B) Increase heart rate and force of contraction
C) Stabilize blood pressure
D) Decrease oxygen consumption
Answer: B) Increase heart rate and force of contraction
Explanation: Adrenaline (epinephrine) stimulates the heart, increasing heart rate and the force of each contraction, especially during stress or exercise.
MCQ 69:
Which of the following is a characteristic of a stroke?
A) Decreased blood flow to the heart
B) Sudden loss of brain function
C) High blood pressure
D) Increased heart rate
Answer: B) Sudden loss of brain function
Explanation: A stroke occurs when blood flow to a part of the brain is interrupted, leading to sudden loss of brain function, such as speech or movement.
MCQ 70:
Which type of blood vessel regulates blood flow and pressure?
A) Capillaries
B) Arteries
C) Veins
D) All of the above
Answer: B) Arteries
Explanation: Arteries have muscular walls that can constrict or dilate to regulate blood flow and maintain blood pressure.
MCQ 71:
What is the role of the heart’s septum?
A) Pump blood
B) Separate the left and right sides of the heart
C) Generate electrical impulses
D) Allow blood to flow freely
Answer: B) Separate the left and right sides of the heart
Explanation: The septum is the wall that divides the heart into left and right sides, preventing mixing of oxygenated and deoxygenated blood.
MCQ 72:
Which part of the heart pumps oxygenated blood to the body?
A) Right atrium
B) Left atrium
C) Left ventricle
D) Right ventricle
Answer: C) Left ventricle
Explanation: The left ventricle pumps oxygenated blood into the aorta for distribution to the rest of the body.
MCQ 73:
Which factor is most important in determining blood type?
A) Plasma proteins
B) Antigens on red blood cells
C) White blood cell count
D) Platelet levels
Answer: B) Antigens on red blood cells
Explanation: Blood type is determined by the presence or absence of specific antigens on the surface of red blood cells.
MCQ 74:
What is the function of the pulmonary valve?
A) Prevent backflow into the right atrium
B) Prevent backflow into the right ventricle
C) Allow blood to flow from the right ventricle to the lungs
D) Regulate blood pressure
Answer: C) Allow blood to flow from the right ventricle to the lungs
Explanation: The pulmonary valve prevents backflow of blood from the pulmonary artery into the right ventricle after blood is pumped to the lungs.
MCQ 75:
Which of the following is a sign of anemia?
A) High blood pressure
B) Increased heart rate
C) Fatigue and weakness
D) Elevated white blood cell count
Answer: C) Fatigue and weakness
Explanation: Anemia often leads to fatigue and weakness due to insufficient oxygen delivery to tissues caused by low red blood cell levels.
MCQ 76:
What is the role of the myocardium?
A) Store blood
B) Contract and pump blood
C) Filter waste
D) Produce hormones
Answer: B) Contract and pump blood
Explanation: The myocardium is the muscular layer of the heart responsible for the contraction and pumping action that circulates blood.
MCQ 77:
Which component of blood helps in fighting infections?
A) Erythrocytes
B) Thrombocytes
C) Plasma
D) Leukocytes
Answer: D) Leukocytes
Explanation: Leukocytes, or white blood cells, are vital for the immune response, helping the body to fight infections and foreign invaders.
MCQ 78:
What is the primary function of the aortic arch?
A) Pump blood
B) Regulate blood pressure
C) Distribute blood to the upper body
D) Return deoxygenated blood to the heart
Answer: C) Distribute blood to the upper body
Explanation: The aortic arch branches off to supply blood to the head, neck, and arms, distributing oxygenated blood from the heart to the upper body.
MCQ 79:
What happens during the cardiac cycle?
A) The heart beats and pumps blood through the body.
B) The heart only relaxes without pumping.
C) Blood only flows in one direction.
D) The heart enlarges and shrinks.
Answer: A) The heart beats and pumps blood through the body.
Explanation: The cardiac cycle consists of all the events that occur during one heartbeat, including both contraction and relaxation phases.
MCQ 80:
Which heart chamber receives deoxygenated blood from the body?
A) Left atrium
B) Right atrium
C) Left ventricle
D) Right ventricle
Answer: B) Right atrium
Explanation: The right atrium receives deoxygenated blood from the body through the superior and inferior vena cavae.
MCQ 81:
What is the function of the renal arteries?
A) Supply blood to the liver
B) Supply blood to the kidneys
C) Carry deoxygenated blood to the heart
D) Regulate blood pressure
Answer: B) Supply blood to the kidneys
Explanation: The renal arteries supply oxygenated blood to the kidneys, where it is filtered to remove waste products.
MCQ 82:
Which term describes the narrowing of blood vessels?
A) Vasodilation
B) Vasoconstriction
C) Vasospasm
D) Aneurysm
Answer: B) Vasoconstriction
Explanation: Vasoconstriction is the narrowing of blood vessels, which can increase blood pressure and reduce blood flow to certain areas.
MCQ 83:
What is the primary function of platelets?
A) Oxygen transport
B) Blood clotting
C) Immune defense
D) Nutrient transport
Answer: B) Blood clotting
Explanation: Platelets are essential for blood clotting, helping to stop bleeding by clumping together at the site of injury.
MCQ 84:
What is the main purpose of the pulmonary circuit?
A) Deliver oxygen to the body’s tissues
B) Remove carbon dioxide from the body
C) Circulate blood within the heart
D) Filter blood in the kidneys
Answer: B) Remove carbon dioxide from the body
Explanation: The pulmonary circuit carries deoxygenated blood from the right side of the heart to the lungs, where carbon dioxide is exchanged for oxygen.
MCQ 85:
What is the effect of high levels of carbon dioxide in the blood?
A) Decrease heart rate
B) Increase heart rate
C) Stabilize blood pressure
D) Decrease respiratory rate
Answer: B) Increase heart rate
Explanation: High levels of carbon dioxide in the blood signal the body to increase heart rate and respiratory rate to enhance the removal of carbon dioxide and improve oxygen intake.
MCQ 86:
What is the function of the right ventricle?
A) Pump oxygenated blood to the body
B) Pump deoxygenated blood to the lungs
C) Receive deoxygenated blood from the body
D) Pump blood to the aorta
Answer: B) Pump deoxygenated blood to the lungs
Explanation: The right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery for oxygenation.
MCQ 87:
What is the role of the hypothalamus in relation to the cardiovascular system?
A) Pump blood
B) Regulate heart rate and blood pressure
C) Filter blood
D) Produce hormones
Answer: B) Regulate heart rate and blood pressure
Explanation: The hypothalamus helps regulate heart rate and blood pressure as part of the body’s response to stress and other stimuli.
MCQ 88:
Which type of blood cell is responsible for forming clots?
A) Erythrocytes
B) Leukocytes
C) Thrombocytes
D) Plasma
Answer: C) Thrombocytes
Explanation: Thrombocytes, or platelets, are crucial for blood clotting, helping to prevent excessive bleeding after an injury.
MCQ 89:
Which of the following structures is involved in the electrical conduction system of the heart?
A) Atrioventricular node
B) Coronary arteries
C) Aorta
D) Pulmonary veins
Answer: A) Atrioventricular node
Explanation: The atrioventricular (AV) node is a key component of the heart’s electrical conduction system, facilitating the transmission of electrical impulses from the atria to the ventricles.
MCQ 90:
What is the role of the jugular veins?
A) Carry deoxygenated blood from the brain
B) Supply blood to the brain
C) Filter blood
D) Pump blood to the heart
Answer: A) Carry deoxygenated blood from the brain
Explanation: The jugular veins are responsible for returning deoxygenated blood from the brain to the heart.
MCQ 91:
What is the primary function of the valves in the heart?
A) Increase blood flow
B) Allow blood to flow in one direction
C) Pump blood
D) Filter blood
Answer: B) Allow blood to flow in one direction
Explanation: Heart valves ensure that blood flows in one direction through the heart and prevent backflow during contractions.
MCA 92:
What is the role of the lymph nodes?
A) Filter blood
B) Store red blood cells
C) Produce platelets
D) Filter lymph fluid and trap pathogens
Answer: D) Filter lymph fluid and trap pathogens
Explanation: Lymph nodes filter lymph fluid, trapping pathogens and foreign substances, and play a vital role in the immune response.
MCQ 93:
What is the primary purpose of the aorta?
A) Transport deoxygenated blood
B) Pump blood
C) Distribute oxygenated blood from the heart
D) Regulate blood pressure
Answer: C) Distribute oxygenated blood from the heart
Explanation: The aorta is the largest artery and distributes oxygenated blood from the heart to the body.
MCQ 94:
Which of the following structures is responsible for maintaining blood pressure?
A) Capillaries
B) Veins
C) Arteries
D) Lymphatics
Answer: C) Arteries
Explanation: Arteries, especially the larger ones like the aorta, maintain blood pressure through their muscular walls that can constrict or dilate.
MCQ 95:
What is the effect of decreased blood volume on blood pressure?
A) Increase blood pressure
B) Decrease blood pressure
C) No effect on blood pressure
D) Stabilize blood pressure
Answer: B) Decrease blood pressure
Explanation: A decrease in blood volume leads to lower blood pressure as there is less fluid exerting pressure on the vessel walls.
MCQ 96:
Which part of the brain controls involuntary actions, including heart rate?
A) Cerebrum
B) Brainstem
C) Cerebellum
D) Hippocampus
Answer: B) Brainstem
Explanation: The brainstem, including the medulla oblongata, controls involuntary actions such as heart rate and breathing.
MCQ 97:
What is the role of the vena cava?
A) Supply oxygenated blood to the heart
B) Return deoxygenated blood to the heart
C) Pump blood to the lungs
D) Filter blood in the kidneys
Answer: B) Return deoxygenated blood to the heart
Explanation: The vena cava consists of the superior and inferior vena cavae, which carry deoxygenated blood from the body back to the right atrium of the heart.
MCQ 98:
What is the primary function of the heart’s atria?
A) Pump blood to the body
B) Receive blood returning to the heart
C) Regulate blood pressure
D) Generate electrical impulses
Answer: B) Receive blood returning to the heart
Explanation: The atria are the upper chambers of the heart that receive blood returning from the body (right atrium) and lungs (left atrium).
MCQ 99:
What is the role of the pulmonary veins?
A) Carry deoxygenated blood to the heart
B) Carry oxygenated blood from the lungs to the heart
C) Filter blood
D) Pump blood to the body
Answer: B) Carry oxygenated blood from the lungs to the heart
Explanation: The pulmonary veins transport oxygenated blood from the lungs to the left atrium of the heart.
MCQ 100:
Which condition is characterized by an irregular heartbeat?
A) Atherosclerosis
B) Arrhythmia
C) Bradycardia
D) Tachycardia
Answer: B) Arrhythmia
Explanation: Arrhythmia refers to any irregularity in the heart’s rhythm, which can affect the heart’s ability to pump blood effectively.
MCQ 101:
What is the main component of plasma?
A) Red blood cells
B) White blood cells
C) Water
D) Platelets
Answer: C) Water
Explanation: Plasma is composed of about 90% water, which serves as a solvent for transporting nutrients, hormones, and waste products.
MCQ 102:
Which blood component is primarily responsible for oxygen transport?
A) Platelets
B) Plasma
C) Erythrocytes
D) Leukocytes
Answer: C) Erythrocytes
Explanation: Erythrocytes, or red blood cells, contain hemoglobin, which binds to oxygen and transports it throughout the body.
MCQ 103:
What is the role of the sinoatrial (SA) node?
A) Pump blood
B) Generate electrical impulses to initiate heartbeats
C) Filter blood
D) Regulate blood pressure
Answer: B) Generate electrical impulses to initiate heartbeats
Explanation: The SA node, located in the right atrium, acts as the heart’s natural pacemaker, generating electrical impulses that initiate each heartbeat.
MCQ 104:
What condition is characterized by high blood pressure?
A) Hypotension
B) Hypertension
C) Anemia
D) Tachycardia
Answer: B) Hypertension
Explanation: Hypertension refers to abnormally high blood pressure, which can lead to various cardiovascular issues.
MCQ 105:
Which of the following is a function of the spleen?
A) Pump blood
B) Store oxygen
C) Filter blood and recycle iron
D) Produce hormones
Answer: C) Filter blood and recycle iron
Explanation: The spleen filters blood, removes old red blood cells, and recycles iron, playing a vital role in the immune system.
MCQ 106:
What does the term “bradycardia” refer to?
A) Rapid heart rate
B) Irregular heartbeat
C) Slow heart rate
D) High blood pressure
Answer: C) Slow heart rate
Explanation: Bradycardia is defined as a slower than normal heart rate, usually below 60 beats per minute.
MCQ 107:
Which type of immunity is provided by antibodies?
A) Innate immunity
B) Adaptive immunity
C) Passive immunity
D) Active immunity
Answer: B) Adaptive immunity
Explanation: Adaptive immunity involves the production of specific antibodies against pathogens, providing a targeted response to infections.
MCQ 108:
What is the primary function of capillaries?
A) Transport blood
B) Regulate blood pressure
C) Exchange substances between blood and tissues
D) Pump blood
Answer: C) Exchange substances between blood and tissues
Explanation: Capillaries are tiny blood vessels where the exchange of gases, nutrients, and waste products occurs between blood and surrounding tissues.
MCQ 109:
What is the role of the pericardium?
A) Pump blood
B) Provide structural support to the heart
C) Protect the heart and reduce friction
D) Generate electrical impulses
Answer: C) Protect the heart and reduce friction
Explanation: The pericardium is a fibrous sac that surrounds the heart, providing protection and reducing friction during heartbeats.
MCQ 110:
Which hormone is primarily responsible for increasing blood pressure?
A) Insulin
B) Adrenaline
C) Estrogen
D) Thyroxine
Answer: B) Adrenaline
Explanation: Adrenaline (epinephrine) increases heart rate and constricts blood vessels, leading to an increase in blood pressure.
MCQ 111:
Which of the following factors can increase the risk of atherosclerosis?
A) Regular exercise
B) High cholesterol levels
C) Low blood pressure
D) Healthy diet
Answer: B) High cholesterol levels
Explanation: High levels of cholesterol can lead to the buildup of plaques in the arteries, increasing the risk of atherosclerosis.
MCQ 112:
What is the main purpose of the coronary circulation?
A) Supply blood to the lungs
B) Supply blood to the heart muscle
C) Transport blood to the brain
D) Return deoxygenated blood to the heart
Answer: B) Supply blood to the heart muscle
Explanation: Coronary circulation refers to the flow of blood to and from the tissues of the heart muscle, ensuring it receives the oxygen and nutrients it needs.
MCQ 113:
Which blood type is known as the universal donor?
A) Type A
B) Type B
C) Type AB
D) Type O
Answer: D) Type O
Explanation: Type O blood can be donated to any blood type because it lacks A and B antigens, reducing the risk of transfusion reactions.
MCQ 114:
What is the primary cause of varicose veins?
A) Increased exercise
B) Poor venous circulation
C) High blood pressure
D) Healthy diet
Answer: B) Poor venous circulation
Explanation: Varicose veins occur when veins become enlarged and twisted due to weakened valves that lead to poor blood flow.
MCQ 115:
Which of the following is NOT a function of blood?
A) Transport of nutrients
B) Regulation of body temperature
C) Protection against pathogens
D) Absorption of oxygen in tissues
Answer: D) Absorption of oxygen in tissues
Explanation: Blood transports oxygen to tissues but does not absorb it; oxygen is absorbed in the lungs and carried by hemoglobin in red blood cells.
MCQ 116:
What is the function of the tricuspid valve?
A) Prevent backflow from the right ventricle to the right atrium
B) Prevent backflow from the aorta to the left ventricle
C) Allow blood flow from the left atrium to the left ventricle
D) Regulate blood flow to the lungs
Answer: A) Prevent backflow from the right ventricle to the right atrium
Explanation: The tricuspid valve ensures that blood flows from the right atrium into the right ventricle and prevents backflow during contraction.
MCQ 117:
Which vitamin is essential for the synthesis of clotting factors?
A) Vitamin A
B) Vitamin B12
C) Vitamin C
D) Vitamin K
Answer: D) Vitamin K
Explanation: Vitamin K is crucial for the synthesis of several clotting factors in the liver, which are necessary for normal blood coagulation.
MCQ 118:
What is the effect of a decrease in oxygen levels on heart rate?
A) Increase heart rate
B) Decrease heart rate
C) No effect on heart rate
D) Stabilize heart rate
Answer: A) Increase heart rate
Explanation: A decrease in oxygen levels stimulates the body to increase heart rate to enhance oxygen delivery to tissues.
MCQ 119:
Which of the following is a function of the circulatory system?
A) Digestion
B) Hormone production
C) Transport of nutrients and waste
D) Immune response
Answer: C) Transport of nutrients and waste
Explanation: The circulatory system transports nutrients to cells and removes waste products, playing a key role in maintaining homeostasis.
MCQ 120:
What type of blood vessel carries oxygenated blood away from the heart?
A) Vein
B) Artery
C) Capillary
D) Lymphatic vessel
Answer: B) Artery
Explanation: Arteries carry oxygenated blood away from the heart to the body, except for the pulmonary arteries, which carry deoxygenated blood to the lungs.
MCQ 121:
Which of the following conditions can result from an embolism?
A) Stroke
B) Heart attack
C) Pulmonary embolism
D) All of the above
Answer: D) All of the above
Explanation: An embolism can block blood flow in any blood vessel, potentially causing a stroke, heart attack, or pulmonary embolism depending on the location.
MCQ 122:
Which component of blood is primarily involved in immune responses?
A) Plasma
B) Erythrocytes
C) Thrombocytes
D) Leukocytes
Answer: D) Leukocytes
Explanation: Leukocytes, or white blood cells, play a key role in the immune system, helping to defend the body against infections.
MCQ 123:
What is the effect of nitric oxide on blood vessels?
A) Constricts blood vessels
B) Dilates blood vessels
C) Increases heart rate
D) Thickens blood
Answer: B) Dilates blood vessels
Explanation: Nitric oxide is a vasodilator, meaning it relaxes the inner muscles of blood vessels, allowing them to widen and improve blood flow.
MCQ 124:
Which part of the circulatory system is responsible for gas exchange?
A) Heart
B) Capillaries
C) Arteries
D) Veins
Answer: B) Capillaries
Explanation: Capillaries are the site of gas exchange, where oxygen is delivered to tissues and carbon dioxide is removed from the blood.
MCQ 125:
What is the role of the femoral artery?
A) Supply blood to the brain
B) Supply blood to the legs
C) Supply blood to the kidneys
D) Return blood to the heart
Answer: B) Supply blood to the legs
Explanation: The femoral artery supplies oxygenated blood to the thigh and leg.
MCQ 126:
Which structure in the heart prevents backflow during contraction?
A) Septum
B) Valves
C) Atria
D) Ventricles
Answer: B) Valves
Explanation: Heart valves prevent the backflow of blood during contraction, ensuring unidirectional blood flow through the heart.
MCQ 127:
What is the primary role of red blood cells?
A) Immune response
B) Blood clotting
C) Oxygen transport
D) Nutrient absorption
Answer: C) Oxygen transport
Explanation: Red blood cells are primarily responsible for transporting oxygen from the lungs to the body tissues.
MCQ 128:
Which type of circulation carries blood to and from the lungs?
A) Systemic circulation
B) Coronary circulation
C) Pulmonary circulation
D) Hepatic circulation
Answer: C) Pulmonary circulation
Explanation: Pulmonary circulation carries deoxygenated blood from the right side of the heart to the lungs for oxygenation and returns oxygenated blood to the left side of the heart.
MCQ 129:
What condition results from the buildup of fatty deposits in arteries?
A) Anemia
B) Atherosclerosis
C) Varicose veins
D) Hypertension
Answer: B) Atherosclerosis
Explanation: Atherosclerosis is a condition characterized by the buildup of fatty deposits (plaques) in arterial walls, leading to reduced blood flow.
MCQ 130:
Which component of blood helps with the immune response by producing antibodies?
A) Erythrocytes
B) Leukocytes
C) Platelets
D) Plasma
Answer: B) Leukocytes
Explanation: Certain types of leukocytes (B cells) produce antibodies that help identify and neutralize pathogens.
MCQ 131:
What is the primary effect of the hormone aldosterone on blood pressure?
A) Decrease blood pressure
B) Increase blood pressure
C) No effect on blood pressure
D) Stabilize blood pressure
Answer: B) Increase blood pressure
Explanation: Aldosterone promotes sodium retention in the kidneys, leading to increased blood volume and, consequently, increased blood pressure.
MCQ 132:
What type of blood vessel is responsible for returning deoxygenated blood to the heart?
A) Artery
B) Capillary
C) Vein
D) Aorta
Answer: C) Vein
Explanation: Veins are blood vessels that return deoxygenated blood back to the heart.
MCQ 133:
What is the main function of the lymphatic system?
A) Pump blood
B) Transport nutrients
C) Drain excess fluid from tissues
D) Produce red blood cells
Answer: C) Drain excess fluid from tissues
Explanation: The lymphatic system drains excess interstitial fluid from tissues, helping to maintain fluid balance and participate in immune responses.
MCQ 134:
What happens during diastole?
A) The heart contracts and pumps blood
B) The heart relaxes and fills with blood
C) Blood is ejected into the lungs
D) Blood pressure decreases
Answer: B) The heart relaxes and fills with blood
Explanation: Diastole is the phase of the cardiac cycle when the heart relaxes and the chambers fill with blood.
MCQ 135:
Which of the following is NOT a function of platelets?
A) Blood clotting
B) Immune response
C) Transporting oxygen
D) Sealing wounds
Answer: C) Transporting oxygen
Explanation: Platelets are involved in blood clotting and sealing wounds but do not transport oxygen; that is the role of red blood cells.
MCQ 136:
Which structure separates the left and right sides of the heart?
A) Valves
B) Septum
C) Atria
D) Ventricles
Answer: B) Septum
Explanation: The septum is a muscular wall that separates the left and right sides of the heart, preventing the mixing of oxygenated and deoxygenated blood.
MCQ 137:
What condition is characterized by low blood oxygen levels?
A) Anemia
B) Hypoxia
C) Hypertension
D) Hypercapnia
Answer: B) Hypoxia
Explanation: Hypoxia refers to low oxygen levels in tissues, which can lead to various health issues if not addressed.
MCQ 138:
Which organ is primarily responsible for filtering blood?
A) Liver
B) Heart
C) Kidneys
D) Spleen
Answer: C) Kidneys
Explanation: The kidneys filter blood to remove waste products and excess substances, producing urine as a byproduct.
MCQ 139:
What is the main function of the aortic valve?
A) Prevent backflow into the left atrium
B) Prevent backflow into the left ventricle
C) Prevent backflow into the right atrium
D) Prevent backflow into the pulmonary artery
Answer: B) Prevent backflow into the left ventricle
Explanation: The aortic valve prevents blood from flowing back into the left ventricle after it has been ejected into the aorta.
MCQ 140:
What is the main purpose of vasodilation?
A) Increase blood pressure
B) Decrease blood flow
C) Increase blood flow to tissues
D) Regulate body temperature
Answer: C) Increase blood flow to tissues
Explanation: Vasodilation widens blood vessels, increasing blood flow to specific tissues and helping to regulate temperature and oxygen delivery.
MCQ 141:
Which type of leukocyte is primarily responsible for fighting bacterial infections?
A) Eosinophils
B) Basophils
C) Neutrophils
D) Lymphocytes
Answer: C) Neutrophils
Explanation: Neutrophils are the most abundant type of white blood cell and are primarily responsible for responding to bacterial infections.
MCQ 142:
What structure helps maintain blood pressure during diastole?
A) Atria
B) Arteries
C) Valves
D) Capillaries
Answer: B) Arteries
Explanation: Arteries maintain blood pressure through their muscular walls that can constrict and regulate blood flow even during diastole.
MCQ 143:
What condition is indicated by an abnormally high level of carbon dioxide in the blood?
A) Hypoxia
B) Hypercapnia
C) Hyperventilation
D) Hypoventilation
Answer: B) Hypercapnia
Explanation: Hypercapnia refers to elevated levels of carbon dioxide in the blood, often resulting from inadequate ventilation.
MCQ 144:
Which part of the heart receives oxygenated blood from the lungs?
A) Right atrium
B) Left atrium
C) Right ventricle
D) Left ventricle
Answer: B) Left atrium
Explanation: The left atrium receives oxygenated blood from the lungs via the pulmonary veins.
MCQ 145:
Which blood vessel is the largest in the body?
A) Pulmonary artery
B) Aorta
C) Vena cava
D) Femoral artery
Answer: B) Aorta
Explanation: The aorta is the largest artery in the body, distributing oxygenated blood from the heart to the rest of the body.
MCQ 146:
What is the role of the atrioventricular (AV) node?
A) Generate electrical impulses
B) Delay impulses between the atria and ventricles
C) Pump blood
D) Filter blood
Answer: B) Delay impulses between the atria and ventricles
Explanation: The AV node delays the electrical impulses from the atria to allow for complete filling of the ventricles before they contract.
MCQ 147:
Which of the following is a risk factor for cardiovascular disease?
A) Regular exercise
B) Healthy diet
C) Smoking
D) Low cholesterol
Answer: C) Smoking
Explanation: Smoking is a major risk factor for cardiovascular disease as it damages blood vessels and promotes the buildup of plaques.
MCQ 148:
What is the purpose of the pulmonary artery?
A) Carry oxygenated blood to the body
B) Carry deoxygenated blood to the lungs
C) Return deoxygenated blood to the heart
D) Supply blood to the brain
Answer: B) Carry deoxygenated blood to the lungs
Explanation: The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs for oxygenation.
MCQ 149:
What is the function of the myocardium?
A) Protect the heart
B) Contract to pump blood
C) Filter blood
D) Generate electrical impulses
Answer: B) Contract to pump blood
Explanation: The myocardium is the muscular layer of the heart responsible for the contraction and pumping of blood throughout the circulatory system.
MCQ 150:
Which blood component plays a key role in immune responses and inflammation?
A) Plasma
B) Erythrocytes
C) Platelets
D) Leukocytes
Answer: D) Leukocytes
Explanation: Leukocytes are crucial for immune responses, helping to identify and eliminate pathogens and participating in inflammation.
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