B1.2.1 The Nervous System

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  1. What is a stimulus?
    A stimulus is a change in your environment which you may need to react to (e.g. a bear looking at you)
  2. What are the 5 different sense organs?
    Eyes, ears, nose, tongue and skin
  3. What is a receptor?
    Receptors are groups of cells that are sentitive to a stimulus. They change stimulus energy (e.g. light energy) into electrical impulses
  4. What can a stimulus be?
    Light, sound, touch, pressure, chemical or a change in position or temperature
  5. What type of receptors do eyes have and what parts does the cell contain?
    Light receptors - sensitive to light and they have a nucleus, cytoplasm and a cell membrane (like most animal cells)
  6. What types of receptors do ears have?
    Sound receptors (sensitive to sound) and balance receptors (sensitive to changes in position)
  7. What type of receptors do noses have?
    Smell receptors (sensitive to chemical stimuli)
  8. What type of receptors do tongues have?
    Taste receptors (sensitive to bitter, salt, sweet, and sour. Also, the taste of savoury things like monosodium glutamate (MSG) - chemical stimuli)
  9. What type of receptors does skin have?
    Receptors that are sensitive to touch, pressure, pain and temperature change
  10. What are sensory neurones?
    The nerve cells that carry signals as electrical impulses from the receptors in the sense organs to the central nervous system
  11. What are relay neurones?
    The nerve cells that carry signals from sensory neurones to motor neurones
  12. What are motor neurones?
    The nerve cells that carry signals from the cemtral nervous system to the effector muscles or glands
  13. What are effectors?
    Muscles and glands are known as effectors - they respond in different ways. Muscles contract in response to a nervous impulse, whereas glands secrete hormones e.g. adrenaline
  14. What is the central nervous system?
    It's where all the information from the sense organs is sent, and where reflexes and actions are coordinated
  15. What does the CNS consist of?
    The brain and spinal cord
  16. In what form is information transmitted along nerve cells?
    Electrical impulses
  17. Where do neurones transmit information to and from?
    The brain
  18. Which is quicker: neurones transmitting information to and from the brain or reflex arcs?
    Reflex arcs
  19. What is a synapse?
    The connection between 2 neurones
  20. What is the main job of the nervous system?
    Coordination and control, awareness of surroundings
  21. Where would you ﬁnd receptors that respond to a loud noise?
  22. Where would you ﬁnd receptors that respond to touching a hot oven?
  23. Where would you find receptors that respond to a strong perfume?
  24. What is the difference between a neurone and a nerve?
    A neurone is a single nerve cell, a nerve is a lot of neurons bundled together
  25. What is the difference between a sensory neurone and a motor neurone?
    A sensory neuron carries impulses from sensory receptors to the CNS, a motor neuron carries impulses from the CNS to the effector organs
  26. Explain what happens in your nervous system when you see a piece of chocolate, pick it up and eat it
    Light from the chocolate is detected by the sensory receptors in the eyes, an impulse travels along the sensory neuron to the brain, information is processed in the brain and an impulse is sent along a motor neurone to the muscles of the arm and hand so you pick up the chocolate and put it in your mouth. The taste receptors on your tongue send information to the brain about taste
  27. Why are reﬂexes important?
    Reﬂ exes protect the body by avoiding danger or damage, to control bodily functions without the need for conscious thought, e.g. breathing
  28. Why is it important that the impulses in a reﬂex arc do not go to the conscious brain?
    They need to be very quick to avoid danger, so the shorter the distance they have to travel, the quicker you will react
  29. Explain why some actions, such as breathing and swallowing, are reﬂex actions, while others such as speaking and eating are under your conscious control
    Reﬂ ex actions that need to operate automatically, even when you are asleep, cannot rely on conscious thought processes, unlike speaking and eating, which we need to be able to choose when to do them
  30. Describe a ﬂow chart to explain what happens when you step on a pin
    Stimulus → receptor → sensory neurone → synapse →chemical message → relay neurone → synapse → chemical message → motor neurone → muscles in leg lift the foot
  31. How do synapses work? (provide a detailed answer)
    An electrical impulse travels along an axon --> this triggers the nerve-ending of a neuron to release chemical messengers called neurotransmitters --> these chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the next neuron --> the receptor molecules on the second neuron bind only to the specific chemicals released from the first neuron --> This stimulates the second neuron to transmit the electrical impulse
  32. In a flow diagram, what is the process when a receptor is stimulated?
    Receptor --> sensory neurone --> CNS --> motor neuron --> effector
  33. In a flow diagram, what is the process of a reflex arc?
    Stimulus-->receptor-->sensory neurone-->relay neurone-->motor neurone-->effector-->response
  34. What part of the nervous system is involved in reflex actions - brain or spinal cord?
    Spinal cord
  35. What are the 2 different types of effector in the human body?
  36. Give 1 difference between a nervous response and a hormonal response
Card Set:
B1.2.1 The Nervous System
2012-11-18 11:03:11
GCSE Biology B1 Nervous System

Covers the nervous system topic in Biology GCSE
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