Why Is the Sinoatrial Node the Heart's Normal Pacemaker

question 175

Multiple Choice

Why is the sinoatrial node the heart's normal pacemaker?

• A)It has the fastest natural rate of autorhythmicity.
• B)It has both sympathetic and parasympathetic innervation.
• C) It is under the control of AV node.
• D) Activation of K⁺ channels occurs more rapidly in this region than elsewhere in the heart.

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