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.
Blood circulates through two bodily systems: the systemic and the pulmonary circulatory systems. The systemic circulatory system is the system that transports the blood from the heart to the other organs and tissues in the body. The human heart is made of four separate chambers. The two top chambers allow blood to enter the heart, while the two lower chambers allow blood to leave the heart.