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    I'm confused as to where the relay neurone is and when the impulses go through? Like, so there's the stimulus, then sensory neurone, then CNS (or relay neurone first?), then motor then effector. Like, is the relay neurone in the CNS/brain/spinal cord only? Is it only used for reflexes? Also, can someone describe these impulses through the neurones? Are they like vibrations? Any help will be deeply appreciated!!
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    (Original post by Perfection Ace)
    I'm confused as to where the relay neurone is and when the impulses go through? Like, so there's the stimulus, then sensory neurone, then CNS (or relay neurone first?), then motor then effector. Like, is the relay neurone in the CNS/brain/spinal cord only? Is it only used for reflexes? Also, can someone describe these impulses through the neurones? Are they like vibrations? Any help will be deeply appreciated!!
    I think it goes: stimulus, receptor cells, sensory neurone to CNS (brain or spinal cord), relay neurone to motor neurone to the effector (muscle/gland) to response The electrical impulses are chemically transmitted across a synapse between 2 neurones
    Hope that helps!


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    (Original post by hettyshaw)
    I think it goes: stimulus, receptor cells, sensory neurone to CNS (brain or spinal cord), relay neurone to motor neurone to the effector (muscle/gland) to response The electrical impulses are chemically transmitted across a synapse between 2 neurones
    Hope that helps!


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    Ahhhh! Okay, now I understand! Thank you!
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    (Original post by Perfection Ace)
    Ahhhh! Okay, now I understand! Thank you!
    I'm glad - good luck!


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    (Original post by Perfection Ace)
    Ahhhh! Okay, now I understand! Thank you!
    And say they diffuse across the synapse.

    EDIT: Say synapse not gap, eventhough the gap is called a synapse we need to use proper science words.
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    I remember the order by SR SR MER (just sing it lol)
    I don't know if it will help anyone else but it certainly helps me.

    First is the stimulus. (S)
    Then the receptors which detect stimuli. (R)
    After that it is the neurones - first is the sensory neurone. (S)
    Then it's the relay neurone. (R)

    Then it's the motor neurone. (M)
    After that it is the effector - muscle or gland. (E)
    Lastly there's a response. (R)

    I can give you an example of what happens when a bee stings you, just let me know. :-)

    The electrical impulses, as mentioned by another poster, are chemically transmitted. This is via a synapse (gap between two neurones). The chemical diffuses across the synapse.
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    (Original post by _Xenon_)
    I remember the order by SR SR MER (just sing it lol)
    I don't know if it will help anyone else but it certainly helps me.

    First is the stimulus. (S)
    Then the receptors which detect stimuli. (R)
    After that it is the neurones - first is the sensory neurone. (S)
    Then it's the relay neurone. (R)

    Then it's the motor neurone. (M)
    After that it is the effector - muscle or gland. (E)
    Lastly there's a response. (R)

    I can give you an example of what happens when a bee stings you, just let me know. :-)

    The electrical impulses, as mentioned by another poster, are chemically transmitted. This is via a synapse (gap between two neurones). The chemical diffuses across the synapse.
    Oo, that's clever! And yes please, I'd like to know the example of a bee sting. Also, can you explain why chemicals diffuse here? Like, how do chemicals transmit the information - that I don't understand. Maybe that's an A level/Uni grade question xD! Anyways, thanks!!
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    (Original post by Perfection Ace)
    Oo, that's clever! And yes please, I'd like to know the example of a bee sting. Also, can you explain why chemicals diffuse here? Like, how do chemicals transmit the information - that I don't understand. Maybe that's an A level/Uni grade question xD! Anyways, thanks!!

    Remember that the reflex arc goes through the CNS (Central nervous system) and that stimuli are changes in the environment that are detected by our body. Receptors are cells which detect stimuli.

    OK. Here is an example:

    1.) A bee stings your hand (stimulus).
    2.) This stimulates the pain receptors.
    3.) The message travels along a sensory neurone.
    4.) The message is passed along a relay neurone.
    5.) The message travels along a motor neurone.
    6.) When the message reaches muscle (effector), it contracts (this is the response).

    The impulse reaches a junction between the sensory neurone and the relay neurone, these junctions between neurones are called synapses. It is at the synapse where a chemical is released. This is what causes an impulse to be sent along the relay neurone. A chemical is released at the synapse between the relay neurone and motor neurone. This triggers an impulse to pass down the motor neurone. The electrical impulse then reaches the effector (in this case a muscle). The arm contracts, leading to the response (the hand moves away).

    I hope this makes sense and answers your question - this is all you need to know for now at least.
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    (Original post by _Xenon_)
    Remember that the reflex arc goes through the CNS (Central nervous system) and that stimuli are changes in the environment that are detected by our body. Receptors are cells which detect stimuli.

    OK. Here is an example:

    1.) A bee stings your hand (stimulus).
    2.) This stimulates the pain receptors.
    3.) The message travels along a sensory neurone.
    4.) The message is passed along a relay neurone.
    5.) The message travels along a motor neurone.
    6.) When the message reaches muscle (effector), it contracts (this is the response).

    The impulse reaches a junction between the sensory neurone and the relay neurone, these junctions between neurones are called synapses. It is at the synapse where a chemical is released. This is what causes an impulse to be sent along the relay neurone. A chemical is released at the synapse between the relay neurone and motor neurone. This triggers an impulse to pass down the motor neurone. The electrical impulse then reaches the effector (in this case a muscle). The arm contracts, leading to the response (the hand moves away).

    I hope this makes sense and answers your question - this is all you need to know for now at least.
    Thanks!! Now I fully understand it!
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    (Original post by Perfection Ace)
    Thanks!! Now I fully understand it!
    You're very welcome. Interested in joining the revision study chat?

    If so, there's an app called Bindle and once you've downloaded it just search #AQAbiology
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    (Original post by _Xenon_)
    You're very welcome. Interested in joining the revision study chat?

    If so, there's an app called Bindle and once you've downloaded it just search #AQAbiology
    Ooo, I'll try it out later! Thanks!
 
 
 
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