A heart will stop beating when the nerves to the heart are severed. Some cardiac cells are self-excitatory. Cardiac cells are coupled by gap junctions. The pacemaker of the heart is the sinoatrial node. The systemic circuit carries oxygenated blood.
Humans have an open circulatory system.
The function of the heart is to make the blood flow through the circulatory system. Excess interstitial fluid is returned to the cardiovascular system via the lymphatic system. Three of the fours answers listed below are related by a common function. Select the exception. Click here to return to the Biology 104 home page.