Heart Beat

• What is the muscle of the heart?

  Cardiac muscle.
• How is cardiac muscle myogenic?

  Its contractions are initiated from within the muscle itself, rather than by nervous impulses.
• Where is the sinoatrial node (SAN)?

  Within the wall of the right atrium of the heart.
• What is the sinoatrial node referred to as and why?

  A pacemaker, as it has a basic rhythm of stimulation that determines the beat of the heart.