The Appeal to Nature (also, Biologizing; The Green Fallacy): The contemporary romantic fallacy of ethos (that of Mother Nature) that if something is natural it has to be good, healthy and beneficial. E.g., Our premium herb tea is lovingly brewed from the finest freshly-picked natural T. Radicans leaves.
Found only in the heart, cardiac muscle is responsible for pumping blood throughout the body. Cardiac muscle tissue cannot be controlled consciously, so it is an involuntary muscle. While hormones and signals from the brain adjust the rate of contraction, cardiac muscle stimulates itself to contract.
In fact there are two pumps that are joined together to work in series. There is a right-sided pump that is responsible for pulling spent blood (blood that has already delivered its nutrients and oxygen) back from the tissues of the body. This blood enters the top chamber of the right heart, called the right atrium.