Describe the events that result in a beating heart

What will be an ideal response?


The SA node sends out a nervous impulse over both atria. The intercalated discs connecting adjacent cardiac muscle cells facilitate this transmission. This results in atrial contraction or atrial systole. In this part of the cycle, blood flows to the ventricles, which are relaxed (they are in diastole). The nervous impulse travels to the AV node, is briefly delayed, and then an impulse is conducted over the ventricles (from the bottom or apex) towards the top, as the great vessels of the heart are oriented at the "top of the heart" (the base). In this part of the cycle, both of the ventricles are in systole, and the blood is pumped through the semilunar valves to the aorta and the pulmonary artery.

Biology & Microbiology

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Biology & Microbiology