Rhythmicity
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| Complete innervation of the heart does not stop the heart from beating e.g. Heart Transplants. | ||||
| Heart starts beating at day 21 of gestation while nerve tissue starts to be formed at day 35. | ||||
Mechanism
| The membrane of the specialised tissue is considered to be a leaky membrane - i.e. not all of the sodium and sodium/calcium channels close during the repolarisation stage. | |
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| Inflow of sodium and calcium ions during the resting stage | |||||
| This inflow of sodium and calcium results in partial depolarisation with the result that a further increase in permeability to sodium and calium ensues | |||||
| This starts off a positive feedback mechanism that once the depolarisation reaches the threshold level, an action potential ensues. | |||||
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