Human body systems flash cards

The cards, front and back

1. 1
   Front

   What is the job of the circulatory system?

   Back

   To carry oxygen, nutrients, hormones and waste around the body in the blood. It is made up of the heart, blood vessels and blood.

2. 2
   Front

   How many chambers does the human heart have?

   Back

   Four: two atria at the top, which receive blood, and two ventricles at the bottom, which pump blood out.

3. 3
   Front

   Why is the human circulatory system called a double circulation?

   Back

   Blood passes through the heart twice on each full circuit: once to go to the lungs to pick up oxygen, and once to be pumped to the rest of the body.

4. 4
   Front

   Arteries, veins and capillaries

   Back

   Arteries carry blood away from the heart under high pressure and have thick muscular walls. Veins carry blood back to the heart and have valves. Capillaries are tiny vessels with walls one cell thick, where substances are exchanged.

5. 5
   Front

   What are the four main parts of blood?

   Back

   Red blood cells carry oxygen using haemoglobin. White blood cells fight infection. Platelets help blood clot. Plasma is the liquid that carries everything else, such as glucose, carbon dioxide and hormones.

6. 6
   Front

   What is the job of the respiratory system?

   Back

   To take oxygen into the body and remove carbon dioxide. Air travels through the trachea, bronchi and bronchioles to the alveoli in the lungs.

7. 7
   Front

   How are alveoli adapted for gas exchange?

   Back

   They give a huge surface area, have very thin walls, a moist lining and a rich supply of capillaries, so gases diffuse quickly between the air and the blood.

8. 8
   Front

   What is the job of the digestive system?

   Back

   To break large, insoluble food molecules into small, soluble ones that can be absorbed into the blood.

9. 9
   Front

   Give the main parts of the digestive system in order.

   Back

   Mouth, oesophagus (esophagus), stomach, small intestine, large intestine, rectum and anus. The liver, gall bladder and pancreas help along the way.

10. 10
    Front

    Where is most digested food absorbed, and how is it adapted?

    Back

    In the small intestine. Its lining is covered in villi, which give a large surface area, have thin walls and a good blood supply.

11. 11
    Front

    Name three digestive enzymes and what they break down.

    Back

    Amylase breaks starch into sugars. Protease breaks proteins into amino acids. Lipase breaks fats into fatty acids and glycerol.

12. 12
    Front

    What does the large intestine do?

    Back

    It absorbs water from the remaining undigested food, which then leaves the body as faeces (feces).

13. 13
    Front

    What is the central nervous system?

    Back

    The brain and the spinal cord. It receives information from receptors and coordinates the body's responses.

14. 14
    Front

    What is a reflex action?

    Back

    A fast, automatic response that does not involve the conscious part of the brain, such as pulling your hand away from something hot. It protects the body from harm.

15. 15
    Front

    What is the endocrine system?

    Back

    A system of glands that release hormones into the blood. Hormones travel to target organs and act more slowly but for longer than nerve impulses.

16. 16
    Front

    What does insulin do?

    Back

    Insulin is a hormone made by the pancreas. It lowers blood glucose by helping cells take in glucose and by causing the liver to store glucose as glycogen.

17. 17
    Front

    Give four jobs of the skeletal system.

    Back

    Support, protecting organs (the skull protects the brain), allowing movement with muscles, and making blood cells in the bone marrow.

18. 18
    Front

    Why do muscles work in antagonistic pairs?

    Back

    Muscles can only pull by contracting, not push. One muscle contracts while the other relaxes, so a pair such as the biceps and triceps can bend and straighten the arm.

19. 19
    Front

    What do the kidneys do?

    Back

    They filter the blood to remove urea, excess water and excess ions, making urine, which is stored in the bladder.

20. 20
    Front

    What is the job of the immune system?

    Back

    To defend the body against pathogens. White blood cells engulf microbes, make antibodies and make antitoxins. Skin and mucus act as barriers.

21. 21
    Front

    What is homeostasis?

    Back

    Keeping the conditions inside the body, such as temperature, blood glucose and water levels, stable even when conditions outside change.