Human Body: Organs, Blood, Brain and Glands MCQs

Solved general science MCQs on the human body: bones, skin, heart and blood pressure, blood cells and groups, lungs, digestion, parts of the brain and the endocrine glands.

1. 1

   How many bones are there in an adult human body?

   A196B212C206D300

   Correct answer: C. 206

   A newborn has about 300 bones, many of which fuse as the body grows, leaving 206 in adults.

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2. 2

   The largest organ of the human body is the:

   ABrainBLungsCSkinDLiver

   Correct answer: C. Skin

   The skin covers about 2 square metres in an adult; the liver is the largest internal organ.

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3. 3

   The normal resting heart rate of an adult is about:

   A40 beats per minuteB72 beats per minuteC110 beats per minuteD150 beats per minute

   Correct answer: B. 72 beats per minute

   A normal adult resting heart rate is 60–100 beats a minute, usually quoted as about 72.

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4. 4

   Normal blood pressure in a healthy adult is about:

   A80/40 mm HgB120/80 mm HgC160/100 mm HgD200/120 mm Hg

   Correct answer: B. 120/80 mm Hg

   The first number (systolic) is the pressure when the heart beats; the second (diastolic) is when it rests between beats.

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5. 5

   The largest artery in the human body is the:

   AFemoral arteryBAortaCPulmonary arteryDCarotid artery

   Correct answer: B. Aorta

   The aorta carries oxygen-rich blood from the left ventricle to the rest of the body.

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6. 6

   Which blood cells fight infection?

   ARed blood cellsBPlasma cells onlyCPlateletsDWhite blood cells

   Correct answer: D. White blood cells

   White blood cells (leucocytes) attack germs and produce antibodies.

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7. 7

   Which part of the blood helps it to clot?

   ARed blood cellsBPlasma proteins onlyCHaemoglobinDPlatelets

   Correct answer: D. Platelets

   Platelets gather at a cut and, with clotting factors, form a plug that stops bleeding.

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8. 8

   A person with which blood group is called a universal recipient?

   ABBACODAB

   Correct answer: D. AB

   AB positive blood has no anti-A or anti-B antibodies, so in an emergency it can receive any ABO group.

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9. 9

   An adult human body contains about how much blood?

   A1–2 litresB5 litresC10 litresD15 litres

   Correct answer: B. 5 litres

   Blood is roughly 7–8% of body weight, about 5 litres in an adult.

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10. 10

    In the lungs, oxygen and carbon dioxide are exchanged in tiny air sacs called:

    ANephronsBAlveoliCBronchiDVilli

    Correct answer: B. Alveoli

    Millions of alveoli give the lungs a huge surface for gases to pass to and from the blood.

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12. 11

    Digested food is mainly absorbed into the blood in the:

    ASmall intestineBLarge intestineCOesophagusDStomach

    Correct answer: A. Small intestine

    Finger-like villi lining the small intestine give a large surface for absorption; the large intestine mainly absorbs water.

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13. 12

    The enzyme in saliva that begins the digestion of starch is:

    ASalivary amylase (ptyalin)BLipaseCPepsinDTrypsin

    Correct answer: A. Salivary amylase (ptyalin)

    Salivary amylase breaks starch into sugars; pepsin digests protein in the stomach.

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14. 13

    Which part of the brain controls balance and coordination of movements?

    AHypothalamusBCerebrumCMedulla oblongataDCerebellum

    Correct answer: D. Cerebellum

    The cerebellum, at the back of the brain, keeps posture and movements smooth and balanced.

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15. 14

    The largest part of the human brain, responsible for thinking, memory and the senses, is the:

    ACerebellumBCerebrumCPonsDMedulla oblongata

    Correct answer: B. Cerebrum

    The cerebrum has two hemispheres and controls voluntary actions, reasoning and memory.

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16. 15

    Involuntary actions such as breathing, heartbeat and swallowing are controlled by the:

    ASpinal cord onlyBCerebrumCMedulla oblongataDCerebellum

    Correct answer: C. Medulla oblongata

    The medulla oblongata, in the brainstem, controls these vital automatic functions.

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17. 16

    The basic structural and functional unit of the nervous system is the:

    ANeuronBAlveolusCAxon onlyDNephron

    Correct answer: A. Neuron

    A neuron (nerve cell) carries electrical signals; the nephron is the unit of the kidney.

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18. 17

    Which gland is called the "master gland" because it controls other endocrine glands?

    APituitaryBAdrenalCPancreasDThyroid

    Correct answer: A. Pituitary

    The pituitary, at the base of the brain, releases hormones that regulate the thyroid, adrenals, growth and reproduction.

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19. 18

    The "fight or flight" hormone adrenaline is produced by the:

    APituitary glandBThyroid glandCAdrenal glandsDPineal gland

    Correct answer: C. Adrenal glands

    The adrenal glands sit above the kidneys; adrenaline raises heart rate and blood sugar in emergencies.

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20. 19

    Thyroxine, which controls the body's rate of metabolism, is secreted by the:

    AThyroid glandBParathyroid glandCPancreasDAdrenal gland

    Correct answer: A. Thyroid gland

    The thyroid needs iodine to make thyroxine; too little iodine causes goitre.

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21. 20

    In the human eye, the image is formed on the:

    ALensBIrisCCorneaDRetina

    Correct answer: D. Retina

    The lens focuses light onto the retina, whose rods and cones send signals to the brain through the optic nerve.

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