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Acetylcholine released by the parasympathetic nerves has which one of thefollowing functions in the heart pacemaker cells

Question

Acetylcholine released by the parasympathetic nerves has which one of the following functions in the heart pacemaker cells?

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Solution

Acetylcholine, which is released by the parasympathetic nerves, plays a crucial role in the functioning of the heart's pacemaker cells. Its primary function is to slow down the heart rate.

Here's a step-by-step explanation:

  1. The parasympathetic nervous system releases acetylcholine, a type of neurotransmitter.

  2. This acetylcholine binds to specific receptors (muscarinic receptors) located on the pacemaker cells in the heart.

  3. Once bound, it opens potassium channels and inhibits the opening of calcium channels in the pacemaker cells.

  4. The opening of potassium channels leads to the outflow of potassium ions, which hyperpolarizes the cell, making it less likely to fire and thus slowing the heart rate.

  5. The inhibition of calcium channels further contributes to the slowing of the heart rate, as calcium ions are necessary for the generation of an action potential, which triggers the contraction of the heart muscle.

So, in summary, acetylcholine released by the parasympathetic nerves slows down the heart rate by affecting the ion channels in the heart's pacemaker cells.

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