The sinoatrial node, or cardiac pacemaker, is ________.
A) electrically active nodal tissue located in the wall of the left ventricle
B) embedded in the anterior two-thirds of the interventricular septum
C) able to cause the atria and ventricles to contract simultaneously
D) able to cause the cardiac muscle to begin to contract at the apex
E) embedded in the posterior wall of the right atrium, near the entrance of the superior vena cava
Ans: E) embedded in the posterior wall of the right atrium, near the entrance of the superior vena cava
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