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Flashcards · Biology · The Nervous System

Scanning and Treating the Brain (Higher tier)

15 cards

  1. Why is it difficult to study the brain directly?

    It is protected by the skull and made of delicate tissue that is easily damaged.

  2. What does a CT scan use?

    X-rays taken from many angles, combined by a computer.

  3. What does a CT scan show?

    The structure of the brain, such as tumours, bleeds and damage.

  4. What does a PET scan use?

    A radioactive tracer, usually a form of glucose.

  5. What does a PET scan show?

    The function of the brain: which areas are active.

  6. Why does a PET scan use glucose?

    Active neurones use more glucose, so the tracer collects in the busiest areas.

  7. Which scan would show a tumour in the brain?

    A CT scan (a PET scan can also show a fast-growing one).

  8. Which scan would show which area is used for speaking?

    A PET scan.

  9. Give one limitation of a CT scan.

    It exposes the patient to X-rays, and it only shows structure, not activity.

  10. Give one limitation of a PET scan.

    It uses a radioactive tracer, it is expensive and it is less detailed.

  11. Why do neurones in the brain make it hard to treat damage?

    They do not regenerate well, so damage is usually permanent.

  12. What is the effect of a severe spinal injury?

    Paralysis and loss of feeling below the injury, because impulses cannot pass.

  13. Why is it hard to remove a brain tumour?

    The tissue is delicate, and a tumour can be near vital areas, so healthy tissue can be damaged.

  14. Why can many drugs not be used to treat the brain?

    A barrier between the blood and the brain stops many chemicals reaching it.

  15. Why are CT and PET scans often used together?

    A CT scan shows the structure and a PET scan shows the activity, so together they give more information.