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Human Anatomy and Physiology - Circulatory and Excretory Systems MCQs 2026

50 questions with detailed answers · 22 from past papers · 5 quiz batches available

📚 Biology Mcqs 📄 22 Past-Paper Qs ✓ Free · No Login Needed
🎯 Mock Test

Read each question, think about the answer, then click Show Answer to reveal the correct option and explanation. Load 10 at a time so it stays manageable — perfect for one-topic study sessions on the bus or during a break.

Page 1 of 1 Questions 1–10 of 50
  1. Q1 easy

    Which of the following is NOT a normal component of blood

    1. A Plasma
    2. B Platelets
    3. C Leukocytes
    4. D Synovial fluid
    💡 Explanation:

    Synovial fluid lubricates joints and is not a component of blood.

  2. Q2 Past Paper · PPSC/FPSC/NTS easy

    The number of chambers in the human heart is

    1. A 2
    2. B 3
    3. C 5
    4. D 4
    💡 Explanation:

    The human heart has four chambers: two atria and two ventricles.

  3. Q3 medium

    The heart chamber that pumps oxygenated blood to the rest of the body is the

    1. A Right atrium
    2. B Left ventricle
    3. C Right ventricle
    4. D Left atrium
    💡 Explanation:

    The left ventricle has the thickest muscular wall since it pumps blood at high pressure through the aorta to the whole body.

  4. Q4 easy

    Blood vessels that carry blood away from the heart are called

    1. A Veins
    2. B Capillaries
    3. C Arteries
    4. D Venules
    💡 Explanation:

    Arteries carry blood away from the heart, usually under high pressure.

  5. Q5 medium

    Which blood cells are mainly responsible for clotting

    1. A Erythrocytes
    2. B Platelets (thrombocytes)
    3. C Leukocytes
    4. D Lymphocytes
    💡 Explanation:

    Platelets aggregate at the site of injury and release factors that trigger the clotting cascade.

  6. Q6 Past Paper · PPSC/FPSC/NTS easy

    The functional and structural unit of the kidney is called

    1. A Alveolus
    2. B Neuron
    3. C Nephron
    4. D Villus
    💡 Explanation:

    Each kidney contains about a million nephrons, which filter blood and form urine.

  7. Q7 Past Paper · PPSC/FPSC/NTS medium

    The universal blood donor group is

    1. A O negative
    2. B AB positive
    3. C A positive
    4. D B negative
    💡 Explanation:

    O negative blood lacks A, B, and Rh antigens, so it can be given to recipients of any blood type in emergencies.

  8. Q8 Past Paper · PPSC/FPSC/NTS medium

    The universal blood recipient group is

    1. A AB positive
    2. B O negative
    3. C A negative
    4. D B positive
    💡 Explanation:

    AB positive blood has both A and B antigens plus Rh factor, so the plasma contains no antibodies against other ABO/Rh types.

  9. Q9 Past Paper · PPSC/FPSC/NTS easy

    The iron-containing protein in red blood cells that carries oxygen is

    1. A Myosin
    2. B Hemoglobin
    3. C Collagen
    4. D Albumin
    💡 Explanation:

    Hemoglobin binds oxygen in the lungs and releases it to body tissues.

  10. Q10 Past Paper · PPSC/FPSC/NTS medium

    The valve located between the left atrium and left ventricle is the

    1. A Tricuspid valve
    2. B Pulmonary valve
    3. C Aortic valve
    4. D Bicuspid (mitral) valve
    💡 Explanation:

    The bicuspid or mitral valve has two flaps and prevents backflow of blood into the left atrium.

  11. Q11 Past Paper · PPSC/FPSC/NTS easy

    The largest artery in the human body is the

    1. A Aorta
    2. B Pulmonary artery
    3. C Carotid artery
    4. D Renal artery
    💡 Explanation:

    The aorta arises from the left ventricle and branches to supply blood to the entire body.

  12. Q12 medium

    Deoxygenated blood is carried from the heart to the lungs by the

    1. A Aorta
    2. B Pulmonary vein
    3. C Vena cava
    4. D Pulmonary artery
    💡 Explanation:

    The pulmonary artery is unusual in carrying deoxygenated blood, from the right ventricle to the lungs.

  13. Q13 Past Paper · PPSC/FPSC/NTS medium

    The natural pacemaker of the heart is the

    1. A Sinoatrial (SA) node
    2. B Atrioventricular (AV) node
    3. C Bundle of His
    4. D Purkinje fibers
    💡 Explanation:

    The SA node, located in the right atrium, initiates the electrical impulse that sets the heart rhythm.

  14. Q14 Past Paper · PPSC/FPSC/NTS easy

    Normal human blood pressure is approximately

    1. A 140/90 mmHg
    2. B 120/80 mmHg
    3. C 100/60 mmHg
    4. D 160/100 mmHg
    💡 Explanation:

    A reading of 120/80 mmHg represents normal systolic over diastolic pressure in a healthy adult.

  15. Q15 Past Paper · PPSC/FPSC/NTS medium

    The instrument used to record the electrical activity of the heart is the

    1. A Sphygmomanometer
    2. B Stethoscope
    3. C Electrocardiograph (ECG)
    4. D Spirometer
    💡 Explanation:

    An ECG records the electrical signals that trigger each heartbeat, helping detect arrhythmias.

  16. Q16 Past Paper · PPSC/FPSC/NTS medium

    Blood circulation between the heart and the lungs is known as

    1. A Systemic circulation
    2. B Portal circulation
    3. C Pulmonary circulation
    4. D Coronary circulation
    💡 Explanation:

    Pulmonary circulation carries deoxygenated blood to the lungs and returns oxygenated blood to the heart.

  17. Q17 medium

    The straw-colored fluid part of blood, obtained after removing the blood cells, is called

    1. A Plasma
    2. B Serum
    3. C Lymph
    4. D Chyme
    💡 Explanation:

    Plasma is the liquid matrix of blood containing water, proteins, and dissolved substances, once the cells are removed.

  18. Q18 easy

    Which blood vessels have walls only one cell thick, allowing exchange of substances with tissues

    1. A Arteries
    2. B Veins
    3. C Capillaries
    4. D Venules
    💡 Explanation:

    Capillaries have thin, permeable walls that permit diffusion of gases and nutrients between blood and tissues.

  19. Q19 Past Paper · PPSC/FPSC/NTS hard

    The Rh blood factor was first discovered in which animal

    1. A Chimpanzee
    2. B Rhesus monkey
    3. C Guinea pig
    4. D Rabbit
    💡 Explanation:

    The Rh antigen is named after the Rhesus monkey, in which it was first identified.

  20. Q20 easy

    White blood cells primarily function in

    1. A Oxygen transport
    2. B Body defense and immunity
    3. C Blood clotting
    4. D Nutrient transport
    💡 Explanation:

    Leukocytes defend the body against infections and foreign invaders.

  21. Q21 medium

    The heart is enclosed by a protective double-layered membrane called the

    1. A Peritoneum
    2. B Pleura
    3. C Meninges
    4. D Pericardium
    💡 Explanation:

    The pericardium encloses the heart and reduces friction as it beats.

  22. Q22 medium

    Which blood vessel carries oxygenated blood from the lungs to the heart

    1. A Pulmonary artery
    2. B Vena cava
    3. C Aorta
    4. D Pulmonary vein
    💡 Explanation:

    The pulmonary vein is unusual in carrying oxygenated blood, from the lungs into the left atrium.

  23. Q23 easy

    Blood pressure is measured using an instrument called a

    1. A Stethoscope
    2. B Thermometer
    3. C Sphygmomanometer
    4. D Barometer
    💡 Explanation:

    A sphygmomanometer measures systolic and diastolic blood pressure in the arteries.

  24. Q24 Past Paper · PPSC/FPSC/NTS easy

    The medical condition of persistently high blood pressure is called

    1. A Hypotension
    2. B Anemia
    3. C Arrhythmia
    4. D Hypertension
    💡 Explanation:

    Hypertension is sustained elevated arterial blood pressure and a major risk factor for heart disease.

  25. Q25 Past Paper · PPSC/FPSC/NTS medium

    Hardening and narrowing of arteries due to fatty deposits is called

    1. A Thrombosis
    2. B Varicose veins
    3. C Aneurysm
    4. D Atherosclerosis
    💡 Explanation:

    Atherosclerosis is caused by plaque buildup on artery walls, reducing blood flow.

  26. Q26 Past Paper · PPSC/FPSC/NTS medium

    The average lifespan of a human red blood cell is about

    1. A 10 days
    2. B 120 days
    3. C 1 year
    4. D 7 days
    💡 Explanation:

    Red blood cells circulate for roughly 120 days before being broken down, mainly in the spleen.

  27. Q27 medium

    Blood is classified as which type of tissue

    1. A Epithelial tissue
    2. B Connective tissue
    3. C Muscular tissue
    4. D Nervous tissue
    💡 Explanation:

    Blood is a fluid connective tissue consisting of cells suspended in plasma.

  28. Q28 medium

    The lymphatic system helps return excess tissue fluid to

    1. A The kidneys
    2. B The liver
    3. C The bloodstream
    4. D The lungs
    💡 Explanation:

    Lymphatic vessels collect excess interstitial fluid and return it to the venous blood circulation.

  29. Q29 hard

    The opening in the fetal heart that allows blood to bypass the non-functional lungs is the

    1. A Foramen ovale
    2. B Ductus deferens
    3. C Semilunar valve
    4. D Interventricular septum
    💡 Explanation:

    The foramen ovale lets blood pass directly from the right atrium to the left atrium in the fetus.

  30. Q30 Past Paper · PPSC/FPSC/NTS medium

    The scientist credited with discovering the circulation of blood is

    1. A Louis Pasteur
    2. B Robert Koch
    3. C William Harvey
    4. D Edward Jenner
    💡 Explanation:

    William Harvey described the systemic circulation of blood pumped by the heart in 1628.

  31. Q31 medium

    The part of the nephron where blood filtration first occurs is the

    1. A Loop of Henle
    2. B Collecting duct
    3. C Distal convoluted tubule
    4. D Glomerulus
    💡 Explanation:

    The glomerulus is a tuft of capillaries where blood pressure forces fluid and solutes into Bowman's capsule.

  32. Q32 medium

    The cup-shaped structure that surrounds the glomerulus is called the

    1. A Loop of Henle
    2. B Renal pelvis
    3. C Collecting duct
    4. D Bowman's capsule
    💡 Explanation:

    Bowman's capsule collects the filtrate produced by the glomerulus as the first step of urine formation.

  33. Q33 easy

    Urine is temporarily stored in the

    1. A Ureter
    2. B Urinary bladder
    3. C Urethra
    4. D Kidney
    💡 Explanation:

    The urinary bladder is a muscular sac that stores urine until it is voided.

  34. Q34 easy

    The tube that carries urine from each kidney to the bladder is the

    1. A Ureter
    2. B Urethra
    3. C Renal vein
    4. D Renal artery
    💡 Explanation:

    Each ureter is a muscular tube that transports urine from the kidney to the bladder by peristalsis.

  35. Q35 Past Paper · PPSC/FPSC/NTS medium

    The main nitrogenous waste product excreted by humans is

    1. A Urea
    2. B Ammonia
    3. C Uric acid
    4. D Creatine
    💡 Explanation:

    Humans are ureotelic, converting toxic ammonia into less toxic, water-soluble urea for excretion.

  36. Q36 hard

    Reabsorption of most filtered water and glucose mainly occurs in the

    1. A Proximal convoluted tubule
    2. B Distal convoluted tubule
    3. C Loop of Henle
    4. D Bowman's capsule
    💡 Explanation:

    The proximal convoluted tubule reabsorbs the bulk of filtered water, glucose, and ions back into the blood.

  37. Q37 Past Paper · PPSC/FPSC/NTS medium

    The hormone that regulates water reabsorption in the kidney tubules is

    1. A Insulin
    2. B Aldosterone
    3. C Renin
    4. D Antidiuretic hormone (ADH)
    💡 Explanation:

    ADH increases water permeability of the collecting duct, concentrating urine and conserving water.

  38. Q38 Past Paper · PPSC/FPSC/NTS medium

    Hemodialysis is a treatment used for patients suffering from

    1. A Diabetes
    2. B Anemia
    3. C Kidney failure
    4. D Hypertension
    💡 Explanation:

    Hemodialysis artificially filters waste and excess fluid from the blood when the kidneys can no longer do so.

  39. Q39 Past Paper · PPSC/FPSC/NTS hard

    Kidney stones are most commonly composed of

    1. A Uric acid crystals
    2. B Cholesterol
    3. C Sodium chloride
    4. D Calcium oxalate
    💡 Explanation:

    Calcium oxalate is the most common mineral found in kidney stones.

  40. Q40 Past Paper · PPSC/FPSC/NTS medium

    Fish primarily excrete nitrogenous waste in the form of

    1. A Ammonia
    2. B Urea
    3. C Uric acid
    4. D Creatinine
    💡 Explanation:

    Fish are ammonotelic; ammonia diffuses directly into the surrounding water, which dilutes its toxicity.

  41. Q41 Past Paper · PPSC/FPSC/NTS medium

    Birds and reptiles excrete nitrogenous waste mainly as

    1. A Uric acid
    2. B Urea
    3. C Ammonia
    4. D Creatinine
    💡 Explanation:

    Uric acid is only slightly soluble and can be excreted as a semi-solid paste, conserving water, which suits egg-laying animals.

  42. Q42 medium

    The outer region of the kidney is called the

    1. A Medulla
    2. B Pelvis
    3. C Cortex
    4. D Capsule
    💡 Explanation:

    The renal cortex is the outer layer of the kidney where most nephron filtration structures are located.

  43. Q43 medium

    The inner region of the kidney containing the renal pyramids is the

    1. A Cortex
    2. B Capsule
    3. C Medulla
    4. D Hilum
    💡 Explanation:

    The renal medulla contains pyramidal structures made up mainly of loops of Henle and collecting ducts.

  44. Q44 easy

    The tube that carries urine out of the body during urination is the

    1. A Ureter
    2. B Urethra
    3. C Renal vein
    4. D Bowman's capsule
    💡 Explanation:

    The urethra conveys urine from the bladder to outside the body.

  45. Q45 medium

    Sweat glands assist excretion mainly by removing

    1. A Water, salts and small amounts of urea
    2. B Bile pigments
    3. C Uric acid only
    4. D Carbon dioxide
    💡 Explanation:

    Sweat is a dilute solution containing water, salts, and trace urea, making skin a minor excretory organ.

  46. Q46 hard

    The liver converts toxic ammonia into less toxic urea through the

    1. A Krebs cycle
    2. B Ornithine (urea) cycle
    3. C Calvin cycle
    4. D Glycolysis
    💡 Explanation:

    The ornithine cycle in liver cells combines ammonia with carbon dioxide to produce urea.

  47. Q47 hard

    An artificial kidney (dialysis) machine works mainly on the principle of

    1. A Osmosis
    2. B Filtration only
    3. C Diffusion across a semi-permeable membrane
    4. D Active transport
    💡 Explanation:

    Dialysis removes wastes by diffusing them across a semi-permeable membrane down their concentration gradient.

  48. Q48 medium

    The renal artery that supplies blood directly to the kidney branches from the

    1. A Pulmonary artery
    2. B Aorta
    3. C Vena cava
    4. D Hepatic artery
    💡 Explanation:

    The renal arteries branch directly off the abdominal aorta to supply the kidneys.

  49. Q49 hard

    The hormone erythropoietin, which stimulates red blood cell production, is secreted mainly by the

    1. A Kidneys
    2. B Liver
    3. C Pancreas
    4. D Spleen
    💡 Explanation:

    The kidneys detect low oxygen levels and release erythropoietin to stimulate bone marrow to make more red blood cells.

  50. Q50 easy

    Which of the following organs is NOT considered part of the excretory system

    1. A Kidney
    2. B Pancreas
    3. C Skin
    4. D Lungs
    💡 Explanation:

    The pancreas is a digestive and endocrine organ; it does not function in excreting metabolic wastes.

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