Circulatory System MCQ Quiz - Objective Question with Answer for Circulatory System - Download Free PDF

Last updated on May 2, 2025

The circulatory system or cardiovascular system is a system in which blood circulates throughout the body. This organ includes blood, blood vessels, and the heart. The main function of this system is to provide oxygen, hormones to musles, and nutrients throughout the body. It also helps in removing waste from cells or the body such as chemical byproducts from your organ, wastes from whatever you eat and drink, and carbon dioxide from respiration. Firstly, you should know the topic well, its functions, and how this system works in a human or animal body. This system continuously works to circulate blood throughout your body. The best approach to attempting the questions of this topic is to learn and practice all the processes and concepts of this topic only then you will be answer all the questions. Below are the sets of questions for your practice.

Latest Circulatory System MCQ Objective Questions

Circulatory System Question 1:

Which of the following is responsible for producing antibodies in humans?

  1. T-cells
  2. B-cells
  3. Red blood cells
  4. Platelets

Answer (Detailed Solution Below)

Option 2 : B-cells

Circulatory System Question 1 Detailed Solution

The correct answer is B-cells.

Key Points

  • B-cells are a type of white blood cell that play a crucial role in the immune system by producing antibodies.
  • Antibodies produced by B-cells are specific proteins that target and neutralize pathogens such as bacteria and viruses.
  • B-cells are part of the adaptive immune system, which provides long-lasting immunity by remembering previous infections.
  • Upon encountering a pathogen, B-cells can differentiate into plasma cells, which are the cells that secrete large quantities of antibodies.

Additional Information

  • T-cells
    • T-cells are another type of white blood cell that play a key role in the immune response by directly killing infected host cells and activating other immune cells.
    • There are different types of T-cells, including helper T-cells, cytotoxic T-cells, and regulatory T-cells, each with specific functions in the immune response.
  • Red Blood Cells (RBCs)
    • RBCs are responsible for transporting oxygen from the lungs to the rest of the body and returning carbon dioxide from the body to the lungs for exhalation.
    • They contain the protein hemoglobin, which binds to oxygen and gives RBCs their red color.
  • Platelets
    • Platelets are small cell fragments that play a critical role in blood clotting and wound healing.
    • They aggregate at the site of a blood vessel injury, forming a plug that helps stop bleeding.
  • Adaptive Immune System
    • The adaptive immune system is a specialized part of the immune system that adapts to specific pathogens and provides long-term immunity.
    • It involves the activation and response of lymphocytes, including B-cells and T-cells, to antigens.

Circulatory System Question 2:

The fourth state of matter 'PLASMA' is a/an ___________.

  1. neutral gas with fewer electrons
  2. ionised gas with ions and electrons in an almost equal number 
  3. state between liquid and gas
  4. ionized gas
  5. Non ionized gas

Answer (Detailed Solution Below)

Option 2 : ionised gas with ions and electrons in an almost equal number 

Circulatory System Question 2 Detailed Solution

The correct answer is ionised gas with ions and electrons in an almost equal number.

Key Points

  • Plasma is one of the four fundamental states of matter, distinct from solid, liquid, and gas.
  • Plasma consists of a collection of free-moving electrons and ions, which are created when atoms in a gas become ionized.
  • In plasma, the number of free electrons and positive ions are approximately equal, making the overall charge of the plasma neutral.
  • Plasma is found naturally in stars, including the sun, and is also created artificially in neon signs and plasma televisions.
  • Plasma can conduct electricity and respond to magnetic fields due to the presence of charged particles.

Additional Information

  • Ionization
    • It is the process by which atoms or molecules gain or lose electrons, resulting in the formation of ions.
    • Ionization can occur due to high temperatures, strong electric fields, or collisions with other particles.
  • Applications of Plasma
    • Plasma is used in various technologies, including fluorescent lights, plasma TVs, and industrial plasma cutting tools.
    • It is also used in space propulsion systems and in the field of nuclear fusion research.
  • Natural Occurrences of Plasma
    • Plasma is commonly found in stars, including the sun, where nuclear fusion occurs at extremely high temperatures.
    • The auroras (Northern and Southern Lights) are also a result of plasma interactions in the Earth's magnetosphere.
  • Properties of Plasma
    • Plasma has unique properties such as high conductivity, the ability to generate magnetic fields, and responsiveness to electric fields.
    • It can exist at a wide range of temperatures and densities, from cold plasma in space to hot plasma in stars.

Circulatory System Question 3:

Carbon monoxide is harmful to human beings as it is:

  1. Carcinogenic
  2. Antagonistic to CO2
  3. With higher affinity for haemoglobin as compared to oxygen
  4. Destructive to O3 (Ozone)
  5. None of the above

Answer (Detailed Solution Below)

Option 3 : With higher affinity for haemoglobin as compared to oxygen

Circulatory System Question 3 Detailed Solution

Concept:

  • Blood is a connective tissue, that has an iron-containing pigment called Haemoglobin.
  • The haemoglobin gives a red colour to the blood and is responsible for the transport of O2 molecules throughout the body.
  • One heme group can carry 4 O2 molecules at a time. Heme group remains in the ferrous state (fe2+) in normal conditions.
  • When haemoglobin combines oxygen from the lungs it forms oxyhaemoglobin.
  • Oxyhaemoglobin transports oxygen to the cells of the body.
  • Oxygen gets attached to Haemoglobin because it shows an affinity towards it, but other gases such as carbon mono-oxide (CO), carbon dioxide (CO2) also shows an affinity towards it.

 

Explanation:

  • When the outside environment is rich in CO, and it is being inhaled, it starts to displace oxygen bind on Haemoglobin.
  • The displacement occurs because CO shows several hundred times stronger affinities towards haemoglobin than oxygen, and it forms carboxyhaemoglobin.
  • This leads to the scarcity of oxygen in the body, and sufficient oxygen is not available for the mind and other organs.
  • Concentrations as low as 20 or 30 parts per million (PPM) can be harmful if exposed for several hours.
  •  Exposure at 2,000 PPM for one hour will cause unconsciousness.
  • The increased concentration of carbon mono-oxide also leads to depletion of Ozone however, this is not the direct reason for why CO is harmful to humans

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Carcinogens:

  • These are the cancer-causing agents, they promote carcinogenesis.
  • Carcinogens stimulate normal body cells to become cancerous cells, and due to uncontrolled growth of these cells tumours are formed.
  • The three main types of carcinogens are:
  •  chemical carcinogens, physical carcinogens, and oncogenic (cancer-causing) viruses.

Circulatory System Question 4:

The main function of Arteries is to carry 

  1. Deoxygenated blood from different parts of the body to the heart
  2. Oxygenated blood from heart to different parts of the body
  3. Oxygenated blood from lungs to different parts of the body
  4. Deoxygenated blood from different parts of the body to the lungs 
  5. None of the above

Answer (Detailed Solution Below)

Option 2 : Oxygenated blood from heart to different parts of the body

Circulatory System Question 4 Detailed Solution

Concept:

Human circulatory system:

  • The human circulatory system, also called the blood vascular system consists of a muscular chambered heart blood vessel and blood.

Heart:

  • The heart is an organ that beats continuously to act as a pump for the transport of blood.
  • The heart, the mesodermally derived organ, is situated in the thoracic cavity, in between the two lungs, slightly tilted to the left.
  • It is protected by a double-walled membranous bag, pericardium, enclosing the pericardial fluid.

Explanation:

Arteries:

  • Arteries carry oxygen-rich blood from the heart to all parts of the body.
  • The arteries have thick elastic walls.
  • Arteries do not have valves.
  • The blood flows in one direction only.

Thus, The main function of Arteries is to carry Oxygenated blood from heart to different parts of the body.

Additional Information Veins:

  • Veins are the vessels that carry carbon dioxide-rich blood from all parts of the body back to the heart.
  • The veins have thin walls.
  • There are valves present in veins that allow blood to flow only towards the heart.

Circulatory System Question 5:

Arteries are best defined as the vessels which

  1. carry blood away from the heart to different organs
  2. break up into capillaries which reunite to form a vein
  3. carry blood from one visceral organ to another visceral organs
  4. supply oxygenated blood to the different organs
  5. None of the above

Answer (Detailed Solution Below)

Option 1 : carry blood away from the heart to different organs

Circulatory System Question 5 Detailed Solution

Key Points

  • In a closed blood circulation system, three types of blood vessels are present: Arteries, Veins & Capillaries

Arteries - 

  • These carry blood away from the heart to different organs of the body.
  • Arteries are made up of 3 layers: 
  1. The intima: It is the innermost layer that is lined by endothelium (a layer of smooth muscle tissue)
  2. The media: It is the middle layer that provides the strength to handle high blood pressure from the heart. The media is the thickest layer
  3. The adventitia: It is the outermost layer that is in direct contact with the surrounding tissue.

Note - 

  • All the arteries carry pure blood except the pulmonary artery which carries impure blood.
  • The pulmonary artery takes impure deoxygenated blood into the lungs from the right ventricle.

​Hence, from the above points, it is clear that arteries​ carry blood away from the heart to different organs. This blood is usually oxygenated but in the case of the pulmonary artery, it is deoxygenated.

Important Points

Important arteries - 

Artery Supply Organ
Carotid artery Carry oxygenated blood to the brainhead neck region of the body
Renal artery  Supply oxygenated blood to the kidney.
Coronary artery Carry oxygenated blood to the muscles of the heart.

Additional Information 

  • Veins:
    • These carry blood away from body organs to the heart.
    • The walls of veins are thin as compared to the arteries because the pressure of blood flow is low.
  • Capillaries:
    • These are present in organs, and these are the vessels through which exchange takes place.

Top Circulatory System MCQ Objective Questions

Which blood group has no antibody?

  1. O
  2. AB
  3. A
  4. B

Answer (Detailed Solution Below)

Option 2 : AB

Circulatory System Question 6 Detailed Solution

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The correct answer is AB.

Key Points

  • Type AB blood is rare it’s found in less than 5% of the population.
  • And it is the 'newest' of the blood types.
  • Until ten or twelve centuries ago, there was little to no Type AB blood type.
  • That is because type AB results from the intermingling of Type A with Type B.
  • Type AB has both A and B antigens, but no antibodies.

 Additional Information

  • In the years 1900–1902, K. Landsteiner divided human blood into four groups — A, B, AB, and O.
  • Rh factor is a type of blood antigen discovered in 1940 by Landsteiner and A.K. s. was done by Veneer.
  • Each person has a blood type (O, A, B, or AB). Everyone also has an Rh factor (positive or negative).
  • The Rh factor is a protein on the covering of the red blood cells.
  • If the Rh factor protein is on the cells, the person is Rh-positive.
  • If there’s no Rh factor protein, the person is Rh-negative.

F1 Alka Singh Anil 11.12.20    D5

Which of the following pairs has a double circulation pathway?

  1. Amphibians and Mammals 
  2. Birds and Mammals 
  3. Reptiles and Mammals 
  4. Fishes and Birds

Answer (Detailed Solution Below)

Option 2 : Birds and Mammals 

Circulatory System Question 7 Detailed Solution

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The correct answer is birds and Mammals.

  • Birds and Mammals have a double circulatory pathway.

Key Points

  • No, mixing of oxygenated and deoxygenated blood in this pathway.
  • The ventricles pump it out without mixing which means two separate circulatory pathways are present in these organisms.
  • Hence, these animals have double circulation.
  • Fishes have single circulatory pathways of circulation which's why known as a single circulation system.
  • In this system oxygenated blood is supplied to the body from where deoxygenated blood is returned to the heart. 
  • In Amphibian and reptiles has incomplete circulation.
  • Here oxygenated and deoxygenated blood gets to mix up within the single ventricle.

Additional Information

  • Types of Circulation and Heart
Characters FIshes Amphibians Reptiles Crocodile Aves Mammals
No of heart chambers 2 3 3 4 4 4
Atria 1 2 2 2 2 2
Ventricles 1 1 1 2 2 2
Type of circulation Single Transitional double Transitional double Double Double Double

The blood vessels that carry blood from the heart to the various parts of the body are called ________.

  1. Arteries
  2. Veins
  3. Septum
  4. Capillaries

Answer (Detailed Solution Below)

Option 1 : Arteries

Circulatory System Question 8 Detailed Solution

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The correct answer is Arteries.

Key Points

  • The blood vessels that carry blood from the heart to the various parts of the body are called Arteries.
  • The main artery is the aorta, the principal high-pressure duct linked to the left ventricle of the heart.
  • The smaller branches of the arteries are called capillaries and arterioles.
  • Veins are vessels of the blood which carry blood to the heart.
  • The septum is the cartilage that divides the heart into right and left chambers, this prevents the mixing of blood.

Additional Information

Arteries Veins Capillaries
Valves are absent. Valves are present. Valves are absent.
Their wall is thicker. Their wall is thin. Their wall is very thin.
Carry blood away from the heart. Carry blood towards the heart. Tiny vessels that connect arteries to veins.
Their blood pressure is high. Their blood pressure is low. Their blood pressure is very low.
Pulse can be felt in this. They have no pulse. They have no pulse.

F1 Anupam Deepak 21.01.2020 D1

Which one of the following is NOT true of WBCs?

  1. Size – 18-25 μm
  2. They act as “soldiers” and eat up the germs
  3. Nucleus - Nucleated
  4. Shape – Irregular shape

Answer (Detailed Solution Below)

Option 1 : Size – 18-25 μm

Circulatory System Question 9 Detailed Solution

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The correct answer is Size - 18-25 µm. 

Key Points

Cells are the basic, fundamental, structural, and functional unit of life responsible for all life's processes, hence they are called Building blocks of life.

On the basis of the count, cells are of three types:- 1. RBCs 2. WBCs 3. Platelets. 

  • RBCs are called red blood cells and help in oxygen transport from the lungs to all body organs and tissues. 
  • WBCs are called white blood cells and help to fight infection and eat up all germs.
  • Platelets help in blood clotting.
RBCs WBCs Platelets 
Life span is 120 days  The life span is 13 to 20 days  Life span is 3 to 7 days
Produced in bone marrow  Produced in the lymph node, spleen, etc. Produced in bone marrow
Due to the presence of hemoglobin, Red in color Due to the absence of hemoglobin, colorless.  Platelets are yellow in color.

Low count of RBCs signifies anemia

Number increases at high altitudes

Low count of WBCs signifies leukopenia

A high count results in infection in the body

A low count of Platelets signifies unusual bleeding

A high count can cause blood clots to develop spontaneously.

Important Points
  • WBCs are also called leukocytes or white corpuscles.
  • The life span of WBCs is 13 to 20 days.
  • Total WBCs count ranges from 4,500 to 10,000.
  • WBCs are a cellular component of the blood that lacks hemoglobin, has a nucleus, is capable of mobility, and producing antibodies.
  • They act as a " Soldier or Guard " of our body.
  • The size of WBCs is 12 to 17 µm in diameter and about three times of RBCs.
  • WBCs do not have any fixed shape, they may be circular, rhomboid or any other shape.

Which type of blood group is known as universal donor?

  1. A
  2. B
  3. AB
  4. O negative

Answer (Detailed Solution Below)

Option 4 : O negative

Circulatory System Question 10 Detailed Solution

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The correct answer is O negative.

Do not confuse with blood group O positive answer, we have provided the link below for better understanding. 

Important Points

  • People with O negative blood group are considered universal donors. RBC's which they contain do not have  A, B, or Rh antigens.
  • People who have a blood group of AB positive are considered as a universal recipient. Those people who have AB positive blood group have an absence of antibodies to A, B, or Rh in their blood.
  • There are four major blood groups: A, B, O, and AB. Blood groups are classification as blood, they are classified on the presence and absence of antibodies and other antigens on the surface of Red blood cells.
  • You can see through this link

https://www.redcrossblood.org/donate-blood/blood-types.html#:~:text=AB-, Group%20O%20can%20donate%20red%20blood%20cells%20to%20anybody.,cells%20to%20B's%20and%20AB's.

Additional Information 

  • Blood is composed of four components: White blood cells, Red blood cells, plasma, and platelets.
  • Red blood cells are red in colour due to the presence of Hemoglobin, which is an iron-containing protein.
  • When viruses or bacteria enter the blood, then White blood cells help in fighting infections.
  • Blood Plasma is a yellowish liquid component of blood that helps in the transportation of nutrients like minerals, protein, vitamins, sugars, and fats to all parts of the body.

F1 Alka Singh Anil 11.12.20    D5

We can see that O- is compatible to donate every other group.

Which vessels carry CO2 rich blood from all parts of the body back to the heart?

  1. Arteries
  2. Veins
  3. Capillaries
  4. Arterioles

Answer (Detailed Solution Below)

Option 2 : Veins

Circulatory System Question 11 Detailed Solution

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The correct answer is Veins.

Key Points

  • The blood vessels carrying the blood from the body towards the heart is called vein.
  • Veins carry CO2 rich blood from all parts of the body back to the heart.
  • Veins carry impure blood.
    • The pulmonary vein is the only vein that carries pure blood.
    • The pulmonary vein carries the blood from the lungs to the left auricle.

Additional Information

  • Arteries carry O2 rich blood from the heart to parts of the body.
    • Arteries carry pure blood.
    • The pulmonary artery is the only artery that carries impure blood.
  • The blood vessels that connect arteries and veins are called Capillaries.
  • Arterioles are the branches of arteries.

Human heart is covered by a double membrane sac called ________.

  1. Plura
  2. Kura
  3. Epicardium
  4. Pericardium

Answer (Detailed Solution Below)

Option 4 : Pericardium

Circulatory System Question 12 Detailed Solution

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The correct answer is Option 4 i.e. Pericardium

  • The pericardium is the outermost covering of the Heart.
  • It is a membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane.
  • The Heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system.
  • The Liver helps in digesting the fat molecules.
  • The Kidney helps in removing the waste and toxins of the body by means of balancing the fluids.
  • Bones help in supporting the body structurally and protect our vital organs.

 

F1 Nayan Deepak 09.01.2020 D3

Which blood vessels carry pure blood from the lungs to the heart? 

  1. Cardiac vein
  2. Pulmonary veins
  3. Pulmonary arteries
  4. Cardiac artery

Answer (Detailed Solution Below)

Option 2 : Pulmonary veins

Circulatory System Question 13 Detailed Solution

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The correct answer is Pulmonary Veins.Key Points

  • The veins that carry oxygenated blood from the lungs to the heart are known as the pulmonary veins.
  • The four primary pulmonary veins—two from each lung—that empty into the left atrium of the heart are the largest pulmonary veins. 
  • The pulmonary veins are part of the pulmonary circulation.
  • The main pulmonary veins receive blood from three or four feeding veins in each lung, and drain into the left atrium.
  • The peripheral feeding veins do not follow the bronchial tree.
  • They run between the pulmonary segments from which they drain the blood.

Additional Information

  • Cardiac vein:
    • The cardiac veins returns deoxygenated blood from the myocardium to the right atrium.
  • Pulmonary arteries:
    • These are blood vessels that carry oxygen-poor blood from the right side of your heart to your lungs.
  • Cardiac artery:
    • These are the arterial blood vessels of coronary circulation, which transport oxygenated blood to the heart muscle.

F3 Madhuri Engineering 25.04.2022 D3

Which is the largest artery in the body?

  1. Aorta
  2. Pulmonary Artery
  3. Coronary arteries
  4. Pulmonary veins

Answer (Detailed Solution Below)

Option 1 : Aorta

Circulatory System Question 14 Detailed Solution

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The correct answer is Aorta.

Key Points

  • The Aorta is the largest artery in the body.
  • The Aorta begins at the top of the left Ventricle which is the Heart's muscular pumping chamber.
  • The Heart pumps blood from the left ventricle into the Aorta through the Aortic valve.

Additional Information

  • Coronary arteries carry oxygenated blood to the muscles of the heart.
    • Any type of hindrance in Coronary arteries causes a heart attack.
  • The Pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
    • The pulmonary artery contains impure blood.
  • Pulmonary veins are responsible for carrying oxygenated blood from the lungs back to the left atrium of the heart.

 

  • The left ventricle pumps oxygenated blood into the aorta via the tricuspid aortic valve.
  • The right atrium receives deoxygenated blood from the vena cavae and coronary sinus and empties it into the right ventricle.
  • The right ventricle pumps deoxygenated blood into the pulmonary trunk via the pulmonary valve.
  • The left atrium receives oxygenated blood from pulmonary veins and empties it into the left ventricle.

Which of the following are NOT a part of the circulatory system?

  1. Capillaries
  2. Villi
  3. Veins
  4. Arteries

Answer (Detailed Solution Below)

Option 2 : Villi

Circulatory System Question 15 Detailed Solution

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The correct answer is Villi.

  • Capillaries are called very tiny blood vessels.
  • The Capillaries expand like a mesh in the whole body.
  • Through these capillaries, blood is transported to all parts of the whole body.
  • The arteries are the blood vessels that carry blood from the heart.
  • All arteries carry oxygen-rich blood, except for pulmonary and avascular arteries.
  • A tube that carries blood from the body to the heart and returns back is called a 'vein'.
  • 'Villy' is a structure found in the intestine that helps to absorb nutrients from the food eaten.
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