Anatomy & Physiology第 64 / 100 题
What is the inherent firing rate of the sinoatrial node in a healthy adult?
a.20 to 40 beats per minute
b.40 to 60 beats per minute
c.60 to 100 beats per minute
d.100 to 150 beats per minute
解析
The SA node in the upper right atrium is the heart's primary pacemaker and fires 60 to 100 times per minute, which is why normal sinus rhythm is defined by that range. The AV junction fires at 40 to 60 as a backup, and the Purkinje network fires at 20 to 40 as the last resort. A rate of 100 to 150 is a tachycardia, not an inherent pacemaker rate.
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