The Cardiac Electrical Impulse Normally Begins Spontaneously in the Sinoatrial

question 24

Multiple Choice

The cardiac electrical impulse normally begins spontaneously in the sinoatrial (SA) node because it:

• A) has a superior location in the right atrium.
• B) is the only area of the heart capable of spontaneous depolarization.
• C) has rich sympathetic innervation via the vagus nerve.
• D) depolarizes between -50 and -60 mV, rather than between -60 and-70 mV.

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