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Exam questions · Biology · The Endocrine System

Hormones and the Endocrine System

  • 7 exam questions
  • 21 marks
  • 8 quick checks
  1. 1 State [2 marks]

    State what is meant by an endocrine gland and a hormone.

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    Model answer

    An endocrine gland releases its hormone into the blood. A hormone is a chemical messenger carried in the blood.

    Mark scheme

    • Endocrine gland releases hormones into the blood — 1 mark
    • Hormone: chemical messenger carried in the blood — 1 mark
  2. 2 Name [3 marks]

    Figure 1 shows some endocrine glands. Name the glands shown at A, B and C.

    A body outline with three glands marked A, B and C.
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    Model answer

    A is the pituitary gland. B is the pancreas. C is an adrenal gland.

    Mark scheme

    • A: pituitary gland — 1 mark
    • B: pancreas — 1 mark
    • C: adrenal gland — 1 mark
  3. 3 Compare [4 marks]

    Compare nervous control with hormonal control.

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    Model answer

    Nervous control uses electrical impulses but hormonal control uses chemicals in the blood. Nervous control is faster than hormonal control. The effect of nervous control is short-lived but hormones have a longer-lasting effect. Nerves act on a precise place whereas hormones act on target organs anywhere in the body.

    Mark scheme

    • Impulses against chemicals in the blood — 1 mark
    • Nervous is faster — 1 mark
    • Hormonal effect lasts longer — 1 mark
    • Precise place against target organs — 1 mark
  4. 4 Explain [3 marks]

    Explain why a hormone only affects some organs, even though it is carried to all parts of the body in the blood.

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    Model answer

    The hormone reaches every organ in the blood. Only its target organs have receptors that fit the hormone. Other organs do not have the receptors, so they do not respond.

    Mark scheme

    • Carried to all organs in the blood — 1 mark
    • Only target organs have the receptors — 1 mark
    • Other organs do not respond — 1 mark
  5. 5 Explain [3 marks]

    Explain how negative feedback keeps the level of thyroxine in the blood roughly constant.

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    Model answer

    If the thyroxine level falls, the pituitary gland releases more hormone to stimulate the thyroid gland, so more thyroxine is made. If the level rises, the pituitary releases less, so the thyroid gland makes less thyroxine. The change is reversed each time.

    Mark scheme

    • Low level makes the pituitary stimulate the thyroid — 1 mark
    • High level makes the pituitary release less — 1 mark
    • Each change causes a response that reverses it — 1 mark
  6. 6 Explain [4 marks]

    Explain how adrenaline helps a person to run away from danger.

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    Model answer

    The adrenal glands release adrenaline. It increases the heart rate and widens blood vessels to the muscles, so more blood reaches them. The liver releases glucose. The muscles get more oxygen and glucose, so they respire faster and release more energy for running.

    Mark scheme

    • Adrenal glands release adrenaline — 1 mark
    • Heart rate increases and more blood to the muscles — 1 mark
    • Liver releases glucose — 1 mark
    • More oxygen and glucose, so more respiration for energy — 1 mark
  7. 7 State [2 marks]

    State two effects of adrenaline on the body.

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    Model answer

    Any two of: increased heart rate, increased breathing rate, liver releases glucose, blood vessels to the muscles widen.

    Mark scheme

    • Effect 1 — 1 mark
    • Effect 2 — 1 mark

Quick check

  1. 1

    What carries hormones around the body?

    1. AThe nerves
    2. BThe lymph
    3. CThe blood
    4. DThe air
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    C: The blood

    Hormones are released into the blood and carried to their target organs.

  2. 2

    Which gland is called the master gland?

    1. AThe pituitary gland
    2. BThe thyroid gland
    3. CThe pancreas
    4. DThe adrenal gland
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    A: The pituitary gland

    The pituitary gland releases hormones that control other glands.

  3. 3

    Which gland releases thyroxine?

    1. AThe pituitary gland
    2. BThe pancreas
    3. CThe adrenal gland
    4. DThe thyroid gland
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    D: The thyroid gland

    The thyroid gland, in the neck, releases thyroxine.

  4. 4

    How does hormonal control compare with nervous control?

    1. AFaster and shorter-lasting
    2. BSlower and longer-lasting
    3. CFaster and longer-lasting
    4. DSlower and shorter-lasting
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    B: Slower and longer-lasting

    Hormonal control is slower, and the effects last longer.

  5. 5

    What is a target organ?

    1. AAn organ that makes hormones
    2. BAn organ in the head
    3. CAn organ with receptors for a hormone
    4. DAn organ that stores hormones
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    C: An organ with receptors for a hormone

    A target organ has receptors that fit a particular hormone.

  6. 6

    Which hormone is released by the testes?

    1. ATestosterone
    2. BOestrogen
    3. CInsulin
    4. DAdrenaline
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    A: Testosterone

    The testes release testosterone.

  7. 7

    What does the thyroid hormone control?

    1. ABlood sugar
    2. BWater balance
    3. CHeart rate only
    4. DMetabolic rate
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    D: Metabolic rate

    Thyroxine controls the basal metabolic rate.

  8. 8

    What is negative feedback?

    1. AA change causes a bigger change
    2. BA change causes a response that reverses it
    3. CA hormone that stays in the blood
    4. DA reflex action
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    B: A change causes a response that reverses it

    In negative feedback a change causes a response that reverses the change.