The Pacemaker Action Potentials in the Heart

question 35

Multiple Choice

The pacemaker action potentials in the heart

• A) are due to opposing actions of norepinephrine and acetylcholine.
• B) are generated by the bundle of His.
• C) depend on the gap junctions between the cells that make up the atria and those that make up the ventricles.
• D) are due to spontaneous depolarization of the plasma membranes of modified cardiac muscle cells.
• E) result from hyperpolarization of cells in the sinoatrial node.

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