Human Circulatory System

40 Grade 6 Integrated Science questions on Human Circulatory System, with worked marking schemes. 40 questions are available on this topic in full.

1. Question 1

   1 mark

   A learner observed blood under a microscope and saw cells that defend the body against germs. Which cells were these?

   A. Platelets

   B. White blood cells

   C. Plasma cells

   D. Red blood cells

   (1 mark)

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2. Question 2

   1 mark

   The smallest blood vessels that connect arteries and veins are called

   A. nerves

   B. capillaries

   C. tubes

   D. pipes

   (1 mark)

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3. Question 3

   1 mark

   Which of the following correctly matches a blood part with its work?

   A. Red blood cells — defending the body against germs

   B. Platelets — carrying oxygen

   C. White blood cells — fighting disease-causing germs

   D. Plasma — clotting wounds

   (1 mark)

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4. Question 4

   3 marks

   Blood performs several important functions in the body. State three functions of blood in the human body. (3 marks)

   (3 marks)

   Marking scheme

   Any three (1 mark each): transports/carries oxygen to body cells; carries digested food/nutrients to the body cells; removes/carries away waste products (e.g. carbon dioxide); fights disease-causing germs; helps in clotting/sealing wounds; distributes heat around the body.

5. Question 5

   4 marks

   The blood is made up of different parts, each with its own work.

   (a) Name any three components of blood. (3 marks)

   (b) State the work of red blood cells. (1 mark)

   (4 marks)

   Marking scheme

   (a) Any three: red blood cells; white blood cells; platelets; plasma (1 mark each, max 3). (b) Red blood cells carry oxygen (from the lungs) to all body parts / cells (1 mark).

6. Question 6

   1 mark

   Which blood vessels carry blood from the body parts back to the heart?

   A. Veins

   B. Windpipes

   C. Arteries

   D. Capillaries

   (1 mark)

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7. Question 7

   1 mark

   High blood pressure can be caused by

   A. exercising regularly

   B. drinking clean water

   C. eating too much salt and fatty foods

   D. eating fruits and vegetables

   (1 mark)

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8. Question 8

   1 mark

   Blood vessels that carry blood away from the heart to the rest of the body are called:

   A. Veins

   B. Capillaries

   C. Nerves

   D. Arteries

   (1 mark)

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9. Question 9

   3 marks

   Arteries and veins are both blood vessels found in the body.

   (a) State one difference between an artery and a vein. (2 marks)

   (b) Name the smallest blood vessels that join arteries to veins. (1 mark)

   (3 marks)

   Marking scheme

   (a) Arteries carry blood away from the heart while veins carry blood back to/towards the heart (2 marks). (Accept: arteries have thicker walls / carry blood at higher pressure than veins.) (b) Capillaries (1 mark).

10. Question 10

    1 mark

    How many chambers does the human heart have?

    A. Two

    B. Three

    C. Five

    D. Four

    (1 mark)

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11. Question 11

    2 marks

    The heart is the organ that pumps blood throughout the body.

    (a) How many chambers does the human heart have? (1 mark)

    (b) Name the body structure that protects the heart. (1 mark)

    (2 marks)

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12. Question 12

    1 mark

    The very thin blood vessels that connect arteries to veins and where food and oxygen pass to the body cells are the:

    A. Capillaries

    B. Veins

    C. Ureters

    D. Arteries

    (1 mark)

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13. Question 13

    1 mark

    White blood cells help the body by

    A. fighting infections and diseases

    B. clotting blood

    C. carrying oxygen

    D. transporting food

    (1 mark)

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14. Question 14

    1 mark

    Which of the following is harmful to the circulatory system and should be avoided?

    A. Playing football

    B. Drinking clean water

    C. Tobacco smoke

    D. Eating fruits

    (1 mark)

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15. Question 15

    1 mark

    Blood flows continuously round the body over and over again. What name is given to this movement of blood?

    A. Respiration

    B. Digestion

    C. Circulation

    D. Reflection

    (1 mark)

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16. Question 16

    1 mark

    Juma cut his finger while cutting sukuma wiki. After a short while the bleeding stopped on its own. Which part of the blood was mainly responsible for stopping the bleeding?

    A. Red blood cells

    B. Plasma

    C. White blood cells

    D. Platelets

    (1 mark)

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17. Question 17

    1 mark

    A doctor told a patient that she had too few red blood cells, a condition called anaemia. Which food would best help the patient?

    A. Sweets and sugary drinks

    B. White bread only

    C. Green vegetables and liver (iron-rich foods)

    D. Cooking oil

    (1 mark)

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18. Question 18

    1 mark

    Which statement about arteries is correct?

    A. They are the thinnest blood vessels in the body

    B. They have thick walls and carry blood at high pressure

    C. They store urine before it leaves the body

    D. They carry blood only to the heart

    (1 mark)

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19. Question 19

    1 mark

    Which of the following habits would best keep the heart and blood vessels healthy?

    A. Sitting for the whole day

    B. Eating a lot of fatty foods daily

    C. Doing regular physical exercise

    D. Smoking cigarettes

    (1 mark)

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20. Question 20

    1 mark

    Which bony structure protects the heart from injury?

    A. The skull

    B. The hip bone

    C. The backbone only

    D. The rib cage

    (1 mark)

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21. Question 21

    1 mark

    Which cells give blood its red colour because they contain haemoglobin that carries oxygen?

    A. Red blood cells

    B. White blood cells

    C. Plasma

    D. Platelets

    (1 mark)

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22. Question 22

    4 marks

    Smoking cigarettes is harmful to the circulatory system. Explain two ways in which smoking can harm the heart and blood vessels. (4 marks)

    (4 marks)

    Marking scheme

    Any two, well explained (2 marks each): smoking damages/narrows the blood vessels/arteries making it harder for blood to flow; it makes the heart work harder / raises heart rate and blood pressure; it can lead to heart disease/heart attack; it reduces the amount of oxygen the blood can carry. (Award 1 mark for the point + 1 mark for the explanation.)

23. Question 23

    2 marks

    After running around the field during games, Achieng noticed her heart was beating much faster than when she was resting. Explain why the heart beats faster during exercise. (2 marks)

    (2 marks)

    Marking scheme

    During exercise the muscles need/use more oxygen and food (energy) (1 mark); so the heart beats faster to pump more blood carrying oxygen and food to the working muscles (and to remove waste faster) (1 mark).

24. Question 24

    3 marks

    When Kamau fell and got a deep cut, the wound bled but soon a clot formed and the bleeding stopped.

    (a) Name the blood component that helped the blood to clot. (1 mark)

    (b) Explain why clotting of blood is important. (2 marks)

    (3 marks)

    Marking scheme

    (a) Platelets (1 mark). (b) Clotting stops/reduces the loss of blood from the body; it also seals the wound to prevent germs from entering the body (2 marks, any two points).

25. Question 25

    1 mark

    Which of the following is a healthy practice for the circulatory system?

    A. Regular exercise and eating a balanced diet

    B. Eating too much fatty food

    C. Smoking cigarettes

    D. Avoiding all physical activity

    (1 mark)

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26. Question 26

    1 mark

    The organ that pumps blood around the body is the

    A. heart

    B. brain

    C. lungs

    D. liver

    (1 mark)

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27. Question 27

    1 mark

    Red blood cells are important because they

    A. help blood clot

    B. fight diseases

    C. produce hormones

    D. carry oxygen around the body

    (1 mark)

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28. Question 28

    1 mark

    A nurse placed two fingers on Amina's wrist and counted the beats for one minute. What was the nurse measuring?

    A. Pulse rate

    B. Body temperature

    C. Blood group

    D. Breathing rate

    (1 mark)

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29. Question 29

    3 marks

    Doctors advise people to take good care of their circulatory system. State three ways in which a person can keep their heart and blood vessels healthy. (3 marks)

    (3 marks)

    Marking scheme

    Any three (1 mark each): doing regular physical exercise; eating a balanced/healthy diet with less fatty food; avoiding smoking/tobacco; avoiding excessive alcohol; getting enough rest/sleep; maintaining a healthy body weight; going for medical check-ups.

30. Question 30

    1 mark

    Blood is carried away from the heart through tubes called

    A. capillaries

    B. veins

    C. nerves

    D. arteries

    (1 mark)

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31. Question 31

    1 mark

    Which component of blood is a pale-yellow liquid that carries the other blood cells and dissolved food around the body?

    A. Platelets

    B. Plasma

    C. Red blood cells

    D. Haemoglobin

    (1 mark)

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32. Question 32

    3 marks

    White blood cells are an important part of the blood.

    (a) State the main work of white blood cells. (1 mark)

    (b) Suggest what might happen to a person if their body had very few white blood cells. (2 marks)

    (3 marks)

    Marking scheme

    (a) White blood cells fight/destroy disease-causing germs (protect the body from disease) (1 mark). (b) The person would fall sick easily / get infections often, because the body cannot fight germs well (2 marks).

33. Question 33

    1 mark

    When you run fast during games, your heart beats faster. This is mainly because the body needs more:

    A. Water in the stomach

    B. Oxygen delivered to the muscles

    C. Light in the eyes

    D. Salt in the blood

    (1 mark)

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34. Question 34

    3 marks

    Blood moves from the heart, through the body, and back to the heart.

    (a) What name is given to the continuous movement of blood round the body? (1 mark)

    (b) Name the two organs directly involved in getting oxygen into the blood and pumping it round the body. (2 marks)

    (3 marks)

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35. Question 35

    1 mark

    Blood is carried back to the heart through

    A. veins

    B. muscles

    C. arteries

    D. capillaries

    (1 mark)

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36. Question 36

    3 marks

    A Grade 6 learner wanted to find out the pulse rate of a classmate.

    (a) Describe how the learner can measure the pulse rate. (2 marks)

    (b) State what the pulse tells us about the heart. (1 mark)

    (3 marks)

    Marking scheme

    (a) Place two fingers on the wrist (or side of the neck) until the pulse is felt; count the number of beats/pulses in one minute (or count for 30 seconds and multiply by 2) (2 marks). (b) It shows how fast/how many times the heart is beating (per minute) (1 mark).

37. Question 37

    4 marks

    A balanced diet helps in the formation of healthy blood.

    (a) Name the condition that results from having too few red blood cells. (1 mark)

    (b) Name two foods that a person with this condition should eat and explain why. (3 marks)

    (4 marks)

    Marking scheme

    (a) Anaemia (1 mark). (b) Iron-rich foods such as green leafy vegetables (e.g. spinach/managu), liver, meat, beans (any two, 1 mark each); because they provide iron needed to make (more) red blood cells / haemoglobin (1 mark for explanation).

38. Question 38

    1 mark

    Which organ pumps blood to all parts of the body?

    A. The liver

    B. The kidney

    C. The heart

    D. The lungs

    (1 mark)

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39. Question 39

    1 mark

    The main work of blood as it moves round the body includes carrying:

    A. Light from the eyes to objects

    B. Sound from the ears to the brain

    C. Bones to different body parts

    D. Oxygen and digested food to body cells

    (1 mark)

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40. Question 40

    1 mark

    In which organ does blood pick up oxygen before returning to the heart?

    A. The skin

    B. The brain

    C. The lungs

    D. The stomach

    (1 mark)

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