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What powers the heart?

  1. Feb 14, 2006 #1
    this may be outdated, but I was under the impression that it was an electrical charge that powered the heart to beat. If so, where does the initial charge come from that started this whole process?

    thanks
    dleacock
     
  2. jcsd
  3. Feb 14, 2006 #2

    matthyaouw

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    The Sinoatrial node (or cardiac pacemaker) doesn't power the heart as such (the heart is muscle fibre and is 'powered' about the same as any other muscle in your body, even though it is of a different muscle type to the rest), but it does send the nerve impulses that cause it to contract.

    http://en.wikipedia.org/wiki/Cardiac_pacemaker
     
    Last edited: Feb 14, 2006
  4. Feb 14, 2006 #3

    HallsofIvy

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    It would be more accurate to say that the electrical charge "triggers" the muscles. For most of us that electrical charge comes from the autonomic nervous system. For people with pacemakers it comes from a battery.
     
  5. Feb 14, 2006 #4

    saltydog

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    ATP. Am I missin' something?
     
  6. Feb 14, 2006 #5
    if the electrical charge comes from the autonomic nervous system, where does that get its charge from? how does it produce an on going charge?

    thanks
    dleacock
     
  7. Feb 14, 2006 #6

    chroot

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    Muscle cells use sugars to produce ATP, which is then used as an energy source throughout the cell -- just like every other cell in the body. The electrical impulses do not power the muscle, they only orchestrate its contractions.

    Electrical potentials are created by cells by using the sodium and potassium pumps, which push charged ions through the cell membrane. These pumps operate using energy from ATP.

    - Warren
     
    Last edited: Feb 14, 2006
  8. Feb 14, 2006 #7

    Monique

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    The pacemaker cells generate electricity by quickly changing their electrical charge from negative to postive and back (by negatively charged ions traveling out through the cell membrane and positively charged ions traveling in), this electrical charge is then conducted through the heart muscle.
     
  9. Feb 15, 2006 #8

    saltydog

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    Duh . . . ATP. Really, I think someone should write a complete description of the biochemical apparatus involved from eating a rasberry truffel to doing a pushup. That's right, all the chemistry, all the molecules, all the physiology.:smile: Who's takin' Biochemistry in here this semester anyway? Sounds like a good project to me. Few weeks oughta' do it.
     
    Last edited: Feb 15, 2006
  10. Feb 15, 2006 #9

    DaveC426913

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    I wonder if the question is simpler than it seems. Perhaps he's wondering, not about the mechanism, but about the actual voltage/amperage source.

    I think saltydog may be closer to the truth than I, but our bodies use Calcium, Potassium, Magnesium and Sodium, all of which like to form ions - thus they have potential differences exploitable by the body.
     
  11. Feb 15, 2006 #10
    Thanks for the info, all the posts were helpfull, but DaveC426913 was a bit closer to what I was thinking about. I had just finished a unit on electricity, voltage, ac/dc, induction all that kind of stuff, and I was trying to think about those things in terms of the heart and all the over all charges that happen in the body.
     
  12. Feb 15, 2006 #11

    Monique

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    Yes you are, describe to me how ATP leads to an electrical current.
     
  13. Feb 17, 2006 #12

    saltydog

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    Well ATP is involved in the action potential via the synapse since binding of various neurotransmitters to their receptors involves ATP thus ATP . . . "leads to an electrical current".
     
  14. Feb 18, 2006 #13

    Monique

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    ATP activates the ATP-sensitive potassium channels, leading to the release of Ca2+ out of the sarcoplasmic reticulum and downstream events.

    To put misunderstandings that were raised in this thread out of the world, I have copied a paragraph from this pdf.

     
  15. Feb 18, 2006 #14

    saltydog

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    Well apparently the discussion is about what controls the beating of the heart and not what is the energy source; the latter of which I believe is ATP. So if I offended anyone by saying "Duh, ATP" I apologize.

    Thanks for the reference Monique.
     
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