Which organ is considered the centre of the circulatory system? — Electrical Engineering MCQ

C. Heart — The heart is the central organ of the circulatory system. It acts as a muscular pump that continuously pumps blood throughout the body. The human heart beats approximately 72 times per minute (at rest) and pumps about 5 litres of blood per minute. It is located in the thoracic cavity, slightly to the left of the centre of the chest.

How many chambers does the human heart have? — Electrical Engineering MCQ

C. 4 — The human heart has 4 chambers: Right Atrium (receives deoxygenated blood from the body), Right Ventricle (pumps deoxygenated blood to the lungs), Left Atrium (receives oxygenated blood from the lungs), and Left Ventricle (pumps oxygenated blood to the entire body). The left ventricle has the thickest wall as it pumps blood against the highest pressure.

What is the normal heart rate (pulse rate) of a healthy adult at rest? — Electrical Engineering MCQ

B. 60-100 beats per minute — The normal resting heart rate for a healthy adult is 60-100 beats per minute (bpm). The average is approximately 72 bpm. Athletes may have lower resting heart rates (40-60 bpm) due to stronger, more efficient hearts. A heart rate above 100 bpm is called Tachycardia and below 60 bpm is called Bradycardia.

Which blood vessels carry blood AWAY from the heart? — Electrical Engineering MCQ

C. Arteries — Arteries carry blood away from the heart to the body tissues (mnemonic: Arteries = Away). Most arteries carry oxygenated blood EXCEPT the pulmonary artery, which carries deoxygenated blood from the right ventricle to the lungs. Arteries have thick, muscular, elastic walls to withstand high blood pressure. The largest artery is the Aorta.

Which blood vessels carry blood TOWARDS the heart? — Electrical Engineering MCQ

D. Veins — Veins carry blood towards the heart. Most veins carry deoxygenated blood EXCEPT the pulmonary veins, which carry oxygenated blood from the lungs to the left atrium. Veins have thinner walls than arteries and contain valves to prevent backflow of blood. The largest veins are the Superior and Inferior Vena Cava.

What is the liquid component of blood called? — Electrical Engineering MCQ

B. Plasma — Plasma is the liquid component of blood, making up approximately 55% of total blood volume. It is a straw-yellow coloured fluid composed of 90% water and contains proteins (albumin, globulin, fibrinogen), hormones, nutrients, waste products, gases, and electrolytes. Serum is plasma without clotting factors (fibrinogen removed).

What percentage of blood is made up of plasma? — Electrical Engineering MCQ

D. 55% — Blood composition: Plasma = 55% (liquid component) and Formed elements = 45% (RBCs, WBCs, platelets). Within the formed elements, RBCs (Red Blood Cells) make up the vast majority (~99%). The percentage of RBCs in total blood is called the Haematocrit (PCV - Packed Cell Volume), which is normally 40-45%.

Which component of blood is responsible for carrying oxygen? — Electrical Engineering MCQ

C. Red Blood Cells — Red Blood Cells (RBCs / Erythrocytes) carry oxygen due to the presence of Haemoglobin - an iron-containing protein that binds to oxygen. Each RBC contains approximately 270 million haemoglobin molecules. RBCs are biconcave disc-shaped, lack a nucleus (in mature form), and have a lifespan of approximately 120 days. They are produced in the red bone marrow.

What is the lifespan of Red Blood Cells (RBCs)? — Electrical Engineering MCQ

D. 120 days — Red Blood Cells (RBCs) have a lifespan of approximately 120 days. After this period, old RBCs are destroyed in the spleen (called the graveyard of RBCs) and liver. The haemoglobin is broken down - the iron is recycled for new RBC production (in bone marrow) and the remaining portion is converted into bilirubin (excreted as bile).

Where are Red Blood Cells (RBCs) produced in adults? — Electrical Engineering MCQ

C. Red Bone Marrow — In adults, RBCs are produced in the Red Bone Marrow - a process called Erythropoiesis. Red bone marrow is found in flat bones like the sternum, ribs, skull, pelvis, and vertebrae. In the fetus, RBCs are initially produced in the yolk sac, liver, and spleen. The hormone Erythropoietin (EPO), produced by the kidneys, stimulates RBC production.

Which protein in RBCs is responsible for oxygen transport? — Electrical Engineering MCQ

C. Haemoglobin — Haemoglobin (Hb) is the iron-containing protein in RBCs that binds oxygen and transports it from lungs to tissues. Normal haemoglobin levels: Men: 13.5-17.5 g/dL, Women: 12-15.5 g/dL. Haemoglobin also transports about 20% of CO2 from tissues to lungs. Low haemoglobin = Anaemia. Haemoglobin bound to oxygen is called Oxyhaemoglobin (bright red), and without oxygen is Deoxyhaemoglobin (dark red).

Which component of blood is responsible for fighting infections? — Electrical Engineering MCQ

C. White Blood Cells — White Blood Cells (WBCs / Leucocytes) are the immune cells of the blood that defend the body against infections, bacteria, viruses, and foreign substances. Normal WBC count: 4,000-11,000 per mm3 of blood. WBCs are of several types: Neutrophils (most common, 60-70%), Lymphocytes, Monocytes, Eosinophils, and Basophils. A high WBC count (Leucocytosis) may indicate infection.

The largest artery in the human body is? — Electrical Engineering MCQ

C. Aorta — The Aorta is the largest and main artery in the human body. It arises directly from the left ventricle and carries oxygenated blood to the entire body (except lungs). The aorta has a diameter of approximately 2.5-3.5 cm. It arches over the heart and descends through the chest and abdomen, branching into smaller arteries that supply all organs and tissues.

The largest vein in the human body is? — Electrical Engineering MCQ

C. Inferior Vena Cava — The Inferior Vena Cava (IVC) is the largest vein in the human body. It carries deoxygenated blood from the lower body (below the diaphragm - legs, abdomen, pelvis) back to the right atrium of the heart. The Superior Vena Cava (SVC) carries deoxygenated blood from the upper body (head, neck, arms) to the right atrium. Together they are the main venous drainage of the body.

What is the normal blood pressure of a healthy adult? — Electrical Engineering MCQ

B. 120/80 mmHg — Normal blood pressure for a healthy adult is 120/80 mmHg. Systolic (120) = pressure when the heart contracts (pumps). Diastolic (80) = pressure when the heart relaxes (fills). Blood pressure >=140/90 = Hypertension (high BP). Blood pressure <90/60 = Hypotension (low BP). Blood pressure is measured using a Sphygmomanometer. Chronic hypertension is a major risk factor for heart attack, stroke, and kidney disease.

Which valve separates the left atrium and left ventricle? — Electrical Engineering MCQ

B. Mitral (Bicuspid) valve — The heart valves and their locations: Tricuspid valve = between Right Atrium and Right Ventricle (3 cusps), Mitral (Bicuspid) valve = between Left Atrium and Left Ventricle (2 cusps), Pulmonary valve = between Right Ventricle and Pulmonary Artery, Aortic valve = between Left Ventricle and Aorta. These valves ensure one-way blood flow and prevent backflow.

What is the function of the Sinoatrial (SA) node? — Electrical Engineering MCQ

B. It acts as the natural pacemaker of the heart — The Sinoatrial (SA) node is a small mass of specialized cardiac muscle tissue located in the right atrium near the entry of the Superior Vena Cava. It generates electrical impulses that initiate each heartbeat - earning it the name Natural Pacemaker of the Heart. The SA node fires approximately 60-100 times per minute, setting the heart rate. The impulse then travels to the AV node and throughout the heart.

The double-layered membrane surrounding the heart is called? — Electrical Engineering MCQ

C. Pericardium — The Pericardium is the double-layered membrane (sac) that surrounds and protects the heart. It consists of: Outer Fibrous Pericardium (tough protective layer) and Inner Serous Pericardium (two layers with pericardial fluid between them that reduces friction during heartbeat). Pleura covers the lungs, Peritoneum covers abdominal organs, and Endocardium is the inner lining of heart chambers.

What is the medical term for high blood pressure? — Electrical Engineering MCQ

C. Hypertension — Hypertension is the medical term for persistently high blood pressure - defined as blood pressure consistently >=140/90 mmHg. It is called the Silent Killer because it usually has no symptoms but causes serious damage to arteries, heart, kidneys, and brain over time. Risk factors include excess salt intake, obesity, stress, smoking, and family history. Treatment includes lifestyle changes and antihypertensive medications.

Which of the following correctly describes systemic circulation? — Electrical Engineering MCQ

B. Blood flow between heart and all body tissues except lungs — Systemic Circulation is the circulation of oxygenated blood from the heart to all body tissues (except lungs) and return of deoxygenated blood back to the heart: Left Ventricle > Aorta > Body Tissues > Superior/Inferior Vena Cava > Right Atrium. This is the larger circuit of the double circulation. The systemic circuit supplies oxygen and nutrients to all organs and removes CO2 and waste products.

A. Blood flow between heart and lungs

C. Blood flow only to the brain

D. Blood flow only to the kidneys

What is the name of the instrument used to measure blood pressure? — Electrical Engineering MCQ

C. Sphygmomanometer — A Sphygmomanometer is the instrument used to measure blood pressure. It consists of an inflatable cuff, pressure gauge, and valve. Blood pressure is measured in mmHg (millimetres of mercury). A Stethoscope is used to listen to heart and lung sounds. An ECG (Electrocardiogram) records the electrical activity of the heart.

The process of formation of blood cells is called? — Electrical Engineering MCQ

B. Haematopoiesis — Haematopoiesis is the process of formation of all blood cells (RBCs, WBCs, platelets) from stem cells in the red bone marrow. Specific terms: Erythropoiesis = formation of RBCs, Leukopoiesis = formation of WBCs, Thrombopoiesis = formation of platelets. All blood cells originate from a common precursor called Haematopoietic Stem Cell (HSC).

Which blood group is known as the 'Universal Donor'? — Electrical Engineering MCQ

D. O — Blood group O (O negative / O-) is called the Universal Donor because it lacks A and B antigens on RBCs, so it can be donated to people of any blood group without causing an immune reaction. Blood group AB is the Universal Recipient because people with AB blood have both A and B antigens and can receive blood from any group. Blood group system was discovered by Karl Landsteiner (Nobel Prize 1930).

Which blood group is known as the 'Universal Recipient'? — Electrical Engineering MCQ

D. AB — Blood group AB is the Universal Recipient because individuals with AB blood have both A and B antigens on their RBCs and no anti-A or anti-B antibodies in their plasma. Therefore, they can receive blood from A, B, AB, or O groups without an immune reaction. However, AB positive (AB+) is the true universal recipient as it also lacks anti-Rh antibodies.

Who discovered the ABO blood group system? — Electrical Engineering MCQ

C. Karl Landsteiner — Karl Landsteiner, an Austrian biologist, discovered the ABO blood group system in 1901. He was awarded the Nobel Prize in Physiology or Medicine in 1930 for this discovery. He later also co-discovered the Rh (Rhesus) factor in 1940 along with Alexander Wiener. The discovery of blood groups made safe blood transfusions possible and revolutionized modern medicine and surgery.

What is Erythroblastosis Fetalis? — Electrical Engineering MCQ

A. A type of anaemia caused by iron deficiency

Which of the following is called the 'Graveyard of RBCs'? — Electrical Engineering MCQ

C. Spleen — The Spleen is called the Graveyard of RBCs because it is the primary site where old, damaged, and worn-out RBCs (after their 120-day lifespan) are destroyed and removed from circulation. The spleen also stores blood, filters blood, and produces lymphocytes. The liver also destroys some old RBCs. The iron from destroyed haemoglobin is recycled for new RBC production.

What is the normal WBC count in human blood? — Electrical Engineering MCQ

B. 4000-11000 per mm3 — Normal White Blood Cell (WBC) count is 4,000-11,000 per mm3 (microlitre) of blood. Leucocytosis = WBC count above normal (indicates infection, inflammation, or leukaemia). Leucopenia = WBC count below normal (indicates bone marrow problems or viral infections). WBCs are far fewer than RBCs (which number 4.5-5.5 million per mm3). The RBC:WBC ratio is approximately 700:1.

Which type of WBC is the most abundant in human blood? — Electrical Engineering MCQ

C. Neutrophils — Neutrophils are the most abundant WBCs, comprising 60-70% of total WBCs. They are the first responders to bacterial infections - they engulf and destroy bacteria through phagocytosis. Types of WBCs and their percentages: Neutrophils 60-70%, Lymphocytes 20-30%, Monocytes 3-8%, Eosinophils 1-4%, Basophils 0.5-1%. Mnemonic: Never Let Monkeys Eat Bananas (N-L-M-E-B).

Which of the following is the correct path of blood in pulmonary circulation? — Electrical Engineering MCQ

B. Right Ventricle > Pulmonary Artery > Lungs > Pulmonary Vein > Left Atrium — The correct path of Pulmonary Circulation: Right Ventricle > Pulmonary Artery (deoxygenated blood) > Lungs (gas exchange: CO2 out, O2 in) > Pulmonary Veins (oxygenated blood) > Left Atrium. Note: The pulmonary artery is the only artery that carries deoxygenated blood, and pulmonary veins are the only veins that carry oxygenated blood.

A. Left Ventricle > Pulmonary Artery > Lungs > Pulmonary Vein > Right Atrium

C. Right Atrium > Pulmonary Vein > Lungs > Pulmonary Artery > Left Ventricle

D. Left Atrium > Pulmonary Artery > Lungs > Pulmonary Vein > Right Ventricle

What is the function of heart valves? — Electrical Engineering MCQ

B. To ensure one-way flow of blood and prevent backflow — Heart valves act like one-way gates that ensure blood flows in a single direction through the heart. They open when blood pressure on one side is higher and close to prevent backflow. The lub-dub sound of the heartbeat is produced by the closing of heart valves: Lub (S1) = closing of Mitral and Tricuspid valves, Dub (S2) = closing of Aortic and Pulmonary valves.

What is the name of the condition where the heart beats abnormally fast (above 100 bpm)? — Electrical Engineering MCQ

B. Tachycardia — Tachycardia = heart rate above 100 bpm (too fast). Bradycardia = heart rate below 60 bpm (too slow). Arrhythmia = any irregular heart rhythm. Fibrillation = rapid, chaotic, uncoordinated contractions (Atrial or Ventricular Fibrillation). Tachycardia can be caused by fever, anxiety, exercise, anaemia, hyperthyroidism, or heart disease. Sustained ventricular tachycardia is a medical emergency.

Which mineral is essential for the production of haemoglobin? — Electrical Engineering MCQ

C. Iron — Iron is the essential mineral required for haemoglobin synthesis. Iron is part of the heme group in haemoglobin - each haemoglobin molecule contains 4 heme groups, each with one iron (Fe2+) atom that binds one oxygen molecule. A total of 4 oxygen molecules are carried per haemoglobin. Iron deficiency leads to Iron Deficiency Anaemia - the most common nutritional deficiency worldwide.

The study of blood and blood disorders is called? — Electrical Engineering MCQ

B. Haematology — Haematology (Greek: haema = blood) is the branch of medicine that deals with the study of blood, blood-forming tissues, and blood disorders. A haematologist diagnoses and treats conditions like anaemia, leukaemia, lymphoma, haemophilia, thalassaemia, and clotting disorders. Cardiology deals with the heart, Nephrology with kidneys, and Oncology with cancer.

What is Anaemia? — Electrical Engineering MCQ

B. Deficiency of haemoglobin or RBCs in the blood — Anaemia is a condition where the blood has a lower than normal number of RBCs or insufficient haemoglobin, resulting in reduced oxygen-carrying capacity. Symptoms: fatigue, pale skin, shortness of breath, dizziness. Types: Iron Deficiency Anaemia (most common), Pernicious Anaemia (Vitamin B12 deficiency), Sickle Cell Anaemia (genetic), Aplastic Anaemia (bone marrow failure), and Haemolytic Anaemia (RBC destruction).

D. Deficiency of platelets in the blood

What is Leukaemia? — Electrical Engineering MCQ

B. Cancer of blood-forming tissues causing abnormal WBC production — Leukaemia is a type of cancer of the blood or bone marrow characterized by the uncontrolled production of abnormal WBCs. These abnormal cells crowd out normal blood cells (RBCs, normal WBCs, platelets), leading to anaemia, infections, and bleeding. Types include Acute/Chronic Lymphocytic Leukaemia (ALL/CLL) and Acute/Chronic Myeloid Leukaemia (AML/CML). Treatment includes chemotherapy, radiation, and bone marrow transplant.

D. Deficiency of plasma proteins

Blood Circulatory System MCQ [ Free PDF Download ] for RRB & SSC and other Competitive exams

Blood Circulatory System MCQ for RRB & SSC and other Competitive exams

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A Heart Attack (Myocardial Infarction) occurs when?

✓ Answer: B Blood supply to the heart muscle is blocked

A Heart Attack (Myocardial Infarction / MI) occurs when blood supply to a part of the heart muscle is blocked (usually by a blood clot in a coronary artery), causing that part of the heart muscle to die from lack of oxygen. Symptoms: chest pain, left arm/jaw pain, shortness of breath, sweating. Caused by Atherosclerosis (plaque buildup in coronary arteries). Immediate treatment with clot-dissolving drugs or angioplasty is critical.

Which component of blood helps in clotting?

✓ Answer: C Platelets (Thrombocytes)

Platelets (Thrombocytes) are small, irregular-shaped cell fragments in the blood that play a crucial role in blood clotting (haemostasis). When a blood vessel is damaged, platelets aggregate at the site and form a platelet plug, initiating the clotting cascade. Normal platelet count: 1,50,000-4,00,000 per mm3. Low platelet count = Thrombocytopenia (risk of bleeding). Platelets have a lifespan of 7-10 days.

What is the Rh factor in blood?

✓ Answer: B An antigen present on the surface of RBCs

The Rh (Rhesus) factor is an antigen (protein) present on the surface of RBCs. People who have the Rh antigen are Rh positive (Rh+), and those who lack it are Rh negative (Rh-). Approximately 85% of humans are Rh+. The Rh factor is clinically important in blood transfusions and pregnancy (Erythroblastosis Fetalis) - when an Rh- mother carries an Rh+ baby.

What is Haemophilia?

✓ Answer: B A genetic disorder where blood does not clot properly

Haemophilia is a hereditary (genetic) bleeding disorder in which blood does not clot properly due to deficiency of clotting factors. Haemophilia A = deficiency of Factor VIII (most common, ~80%). Haemophilia B = deficiency of Factor IX (Christmas disease). It is an X-linked recessive disorder - affects males predominantly (females are carriers). Even minor injuries can cause prolonged bleeding. Treatment involves replacement of deficient clotting factors.

What is the normal blood volume in an adult human body?

✓ Answer: B 4-6 litres

The average adult human body contains approximately 4-6 litres of blood (about 5 litres for an average 70 kg adult). Blood volume is approximately 7-8% of body weight. The total blood volume includes plasma (55%) and formed elements - RBCs, WBCs, and platelets (45%). Blood volume varies with body size, age, sex, and hydration status.

What is Erythroblastosis Fetalis?

✓ Answer: B A condition where maternal antibodies destroy fetal RBCs due to Rh incompatibility

Erythroblastosis Fetalis (Haemolytic Disease of the Newborn) occurs when an Rh- mother carries an Rh+ fetus. During delivery, fetal Rh+ blood enters the mother's circulation, causing her to produce anti-Rh antibodies. In a subsequent Rh+ pregnancy, these antibodies cross the placenta and destroy the fetal RBCs, causing severe anaemia, jaundice, and potentially death. Prevented by injecting Anti-D immunoglobulin (Rh immunoglobulin) to the mother.

Which of the following is the correct statement about capillaries?

✓ Answer: C Capillaries are microscopic vessels where exchange of gases and nutrients occurs

Capillaries are the smallest and most numerous blood vessels - microscopic in size (diameter ~5-10 micrometres). They form networks (capillary beds) throughout all tissues. Their walls are only one cell thick (endothelium), allowing exchange of oxygen, CO2, nutrients, waste products, and hormones between blood and tissue cells. Arteries branch into arterioles > capillaries > venules > veins.

Which type of blood circulation carries blood between the heart and lungs?

✓ Answer: B Pulmonary circulation

Pulmonary Circulation is the circulation of blood between the heart and lungs for oxygenation: Right Ventricle > Pulmonary Artery > Lungs > Pulmonary Veins > Left Atrium. Deoxygenated blood is sent to lungs, oxygenated blood returns to heart. Systemic Circulation carries oxygenated blood from Left Ventricle > body tissues > Right Atrium. Together they form the Double Circulation in humans.

The inner lining of the heart chambers is called?

✓ Answer: C Endocardium

The heart wall has three layers: Endocardium (innermost layer, smooth lining of heart chambers and valves), Myocardium (middle layer, thick muscular layer responsible for heart contractions), and Epicardium (outermost layer of the heart wall, also called visceral pericardium). The Pericardium is the outer membranous sac surrounding the entire heart. The Myocardium is the thickest layer - especially in the left ventricle.

An ECG (Electrocardiogram) is used to measure?

✓ Answer: C Electrical activity of the heart

An ECG (Electrocardiogram) records the electrical activity of the heart using electrodes placed on the skin. It detects the electrical impulses that cause the heart to contract and produces a characteristic waveform: P wave (atrial depolarization), QRS complex (ventricular depolarization), and T wave (ventricular repolarization). ECG is used to diagnose heart attacks, arrhythmias, and heart enlargement.

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