Most Important MCQ of Circulatory System

Circulatory System is a network of organs that permit blood circulation. The circulatory system’s other name is the cardiovascular system or the vascular system. The primary function of the circulatory system  is  to transport blood to each part of the body, it is necessary because it carries nutrients, oxygen, carbon dioxide, hormones, and blood cells that are necessary for the hydration and growth of each organ’s cell population

The following questions are useful in SSC, banking, and other government exams like PGT, TGT

Que 1. At which point, the right ventricle contracts, and blood is pumped out.
a) Superior vena cava
b) Dorsal aorta
c) Pulmonary aorta
d) Pulmonary veins

Ans-(c) Pulmonary aorta

• Right atrial blood flows into the right ventricle (RV). Right ventricular pressure increases as the right ventricle fill up and the walls of the ventricle start to contract.
• As a result of the tricuspid valve being closed by increased pressure, the pulmonic valve pumps blood into the pulmonary artery.
• There are two sections to the pulmonary artery.
• The left lung receives the other while the right lung receives the first.
• It is the only artery that connects the heart and lungs with blood that has lost oxygen.

Que 2. Who operates the first heart transplant procedure?
a) William Harvey
b) Watson
c) Christian Bernard
d) Khorana

Ans-(c) Christian Bernard

• Christiaan Neethling Barnard, a South African cardiac surgeon who is regarded as the founder of heart transplantation, carried out the first successful human-to-human heart transplant on December 3, 1967.
• The world’s media reported on the patient’s improvement virtually hourly. 
• Although Mr. Louis Washansky, the patient, passed away after just 18 days, Barnard quickly performed a second transplant, and this patient went on to live an active life for almost 19 months.

Que 3. Which part of the body can be called a kind of “blood bank”:
a) Heart
b) Liver
c) Spleen
d) Lungs

Ans-(c ) Spleen

• Spleen is referred to as a blood bank because it is cleaned the blood filtering and storing blood cells for an emergency situation like Hemorrhagic Shock
• Spleen is another name for the “graveyard of blood” as it purifies the blood by removing microbes and worn-out RBCs.
• The spleen is placed beneath the ribcage and much above the stomach (upper left of the abdomen) under the diaphragm.

Que 4. Which of the following arteries does not carry oxygenated blood?
a) Systemic
b) Hepatic
c) Pulmonary
d) Cardiac

Ans- ( c) Pulmonary

• In the human body, the pulmonary artery DOES NOT transport oxygenated blood.

Que 5. Which of the following has a closed-type circulatory system?
a) Cockroach
b) Fish
c) Mollusca
d) Scorpion

Ans-(b) Fish

• Phylum Arthropoda and Mollusca are related and include an open circulatory system. 
• Fish belong to the phylum Chordata which consists of a close circulatory system. 
• Cockroaches and scorpions are part of the class Insecta phylum Arthropoda.

Que 6. The study of the blood circulatory system is called 
a)  Angiology
b) Cardiology
c)  Hematology
d) Osteology

Ans-(a) Angiology

• The study of the blood circulatory system is called Angiology
• The medical term “angiology” refers to the study of illnesses affecting the lymphatic and circulatory systems, namely arteries, veins, and lymphatic vessels.

Que 7. By which type of tissue the atrioventricular septum composed of?
a) Cartilage
b) Fibrous tissue
c) Osteocytes
d) Mucous membrane

Answer- ( b) Fibrous tissue

• It is made up of an extension or crest of the interventricular septum on the left and anterior membranous and inferior muscular parts that emerge from the right atrial septal wall.
• Two atria and two ventricles make up the four chambers of the human heart.
• They circulate blood to the body’s various organs.
• The atria and ventricles are divided by the atrioventricular septum.
• The fibrous and adipose tissues that make up the atrioventricular septum.

Que 8. Which of these structures is nearest to the atrioventricular node?
a) SAN
b) Left ventricle
c) Atrio-ventricular septum
d) Aorta

Answer: (c ) Atrio-ventricular septum

• The heart contains a tiny component called the atrioventricular (AV) node.
• The AVN or the atrioventricular node is located in the lower-left corner of the right atrium. 
• It is located nearby the atrioventricular septum which separates the atria and the ventricles.

Que 9. Which of the following parts of the body is called the heart’s pacemaker?
a) Purkinje fibers
b) AVN
c) Sinus Node
d) Bundle of His

Answer: ( c )Sinus Node (SAN)

• The SA (sinus) node is a collection of myocytes that are active pacemakers.
• The sinus node is referred to as the “natural pacemaker” of the heart.
• The Sinus Node can produce 70–75 action potentials each minute, which start the heart muscles contracting.

Que 10. What is the approximate weight of the human heart?
a) 250- 300 gm
b) 250- 350 gm
c) 350- 450 gm
d) 300- 400 gm

Ans-(a) 250- 300gm

• The size of the human heart is the same as that clenched fist. 
• The adult human heart weighs between 250 to 350 gm. 
• It makes up about 0.45% of the total weight of the body. 
• Depending on your physical size and sex, your heart may weigh a little more or a little less.

Que 11. Which of the following are NOT a component of the circulatory system?
a) Capillaries
b) Villi
c) Veins
d) Arteries

Ans-(b) Villi

• Very tiny blood vessels are referred to as capillaries.
• The body’s capillaries spread out like a mesh.
• Blood is carried to every area of the body by way of these capillaries.
• The blood channels that convey blood away from the heart are known as arteries.
• Except for the pulmonary and avascular arteries, all arteries contain blood that is rich in oxygen.
• A “vein” is a tube that transfers blood from the body to the heart and back again.
• Villi is a component of the gut that aids in the absorption of nutrients from food.

Que 12. Where are produced red blood cells?
a) Heart
b) Lymph Nodes
c) Liver
d) Bone Marrow

Ans-( d) Bone Marrow

• Bone Marrow is the soft tissue found inside the Medullary cavities of a bone 
• It is primarily placed in the hip and thigh bones. 
• Bone marrow generates immature cells called Stem cells that can develop into various types of cells later on. 
• Bone marrow produces two different types of stem cells: mesenchymal and hematopoietic
• Mesenchymal cells develop into fat cartilage and bones
• whereas Hematopoietic cells develop and turn into Blood cells (RBC, WBC, and Platelets)

Que 13. A double membrane sac known as the _______ protects the human heart.
a) Plura
b) Kura
c) Epicardium
d) Pericardium

Ans-(d) Pericardium

• The pericardium is the heart’s outermost layer of protection.
• It is a membrane that surrounds the heart and is made up of an inner double layer of serous membrane and an outside fibrous layer.
• In most animals, the heart is a muscular organ that pumps blood by the circulatory system to the blood arteries.
• The liver aids in the breakdown of fat molecules.
• For maintaining a healthy balance of fluids, the kidney aids in the removal of waste and poisons from the body.
• Bones protect our important organs and assist in structural bodily support.

Que 14. Which of the following is the largest artery of the human body?
a) Coronary arteries
b) Pulmonary artery
c) Aorta
d) None of the above

Ans-(c) Aorta

• The aorta is the body’s largest artery.
• The main artery that transports blood from your heart to the rest of your body is called the aorta.
• The heart’s muscles receive oxygenated blood from the coronary arteries.
• A heart attack is brought on by any kind of obstruction in the coronary arteries.
• Deoxygenated blood is delivered to the lungs by the pulmonary artery from the right ventricle.
• The blood in the pulmonary artery is contaminated.
• The task of returning oxygenated blood from the lungs to the left atrium of the heart is performed by pulmonary veins.

Que 15. What components serve as doors to regulate the heart’s blood flow?
a) Valves
b) Heart dams
c) Kidneys
d) Chambers

Ans-(a) Valves

• There are four heart valves, which function as doors between the chambers of the heart. 
• They flutter open and close as your heart pumps. 
• The valves are only open in one direction. 
• This prevents blood from flowing in the wrong way between the chambers of your heart.
• The atrioventricular (AV) valves open b/w the upper and lower heart chambers.

Que 16. In which of the following excess blood is stored and released when there is deficiency?
a) Adrenal gland
b) Pancreas
c) Spleen
d) Thyroid gland

Ans-(c) Spleen

• In the body, the spleen serves a variety of supportive functions.
• As a component of the immune system, it filters blood.
• The spleen stores platelets and white blood cells in addition to recycling old red blood cells.
• Additionally, certain types of germs that cause meningitis and pneumonia are combated by the spleen.
• Your spleen has the capacity to store up to a cup of reserve blood when the arteries are opened up.
• In response, your spleen may discharge that reserve blood into your body.

Que 17.  What is Inadequate blood supply in the human body is called?
a) Ischemia
b) Hyperemia
c) Hemostasis
d) Hemorrhage

Answer (a) Ischemia

• Ischemia is the medical term for inadequate blood supply in humans.
• Ischemia is a condition when the blood flow (and thus oxygen) is decreased or restricted in a particular bodily region.
• The term “cardiac ischemia” refers to the heart muscle’s reduced blood flow and oxygenation.
• Usually, your heart’s arteries are partially or completely blocked, which causes lower blood flow (coronary arteries).

Que 18. What is the normal pH of Human Blood?
a) 7.4
b) 7.2
c) 7.8
d) 6.6

Answer (a) 7.4

• Blood’s pH typically falls between 7.35 and 7.45, making it mildly basic.
• To determine whether a substance is acidic or basic, one can use the pH scale.
• The scale has a range of 0 to 14 .
• 7 is regarded as neutral pH.
• In German, the letter pH stands for “potenz,” which means “power” pH can be termed as “Power of Hydrogen”.

Que 19. Which component in the blood acts as an anticoagulant?
a) Fibrinogen
b) Thrombin
c) Globin
d) Heparin

Ans-(d) Heparin

• The Heparin component in the blood acts as an anticoagulant.
• Heparin connects to serine protease inhibitor antithrombin III (AT) which results in activation of AT.
• The activated AT blocks thrombin and blocked factors Xa and IIa which are responsible for blood coagulation.

Que 20.  Which of the following minerals ions play the main role in blood clotting?
a) Mg
b) Na
c) Ca
d) K

Ans- (c) Ca

• Calcium is the mineral ion that is responsible for the cause of blood clots. 
• Blood clots are created by the activation of several clotting factors, which are activated by calcium.