Outline the control of the heart beat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain, epinephrine (adrenaline)

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Outline the control of the heart beat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain, epinephrine (adrenaline)

The human heart is a double circulatory system, which consists of the pulmonary circulation and the systemic circulation. In the pulmonary circulation, the heart pumps the deoxigenated blood from the heart through the pulmonary artery to the lungs and from there it pumps the oxigenated blood through the pulmonary vein back to the heart. In the systemic circulation, the oxigenated blood is pumped through the aorta to the body and back to the heart through the vena cava. To produce the necessary pressure to pump the blood through the body, the heart has to contract and squeeze the blood out of it. This is known as the cardiac cycle. The cardiac cycle has three phases: the atrial systole, the ventricular systole and the diastole. In the atrial systole the blood is squeezed from the contracting atria into the relaxing ventricles. In the ventricle systole the ventricles contract and pump the blood out of the heart whereas the atria relax and refill. In the diastole the whole heart is relaxed and it refills. The