Herz

Herz is the German noun for the heart, the muscular organ that functions as the central component of the circulatory system. In humans and many animals, the heart acts as a two-sided pump that circulates blood: it sends oxygen-rich blood from the left ventricle to the body and returns deoxygenated blood to the right atrium through the lungs for reoxygenation.

It comprises four chambers—the left and right atria and the left and right ventricles—separated by valves that maintain unidirectional blood flow: the atrioventricular valves (mitral and tricuspid) and the semilunar valves (aortic and pulmonary). The myocardium contracts in a rhythmic sequence directed by the cardiac conduction system, with the sinoatrial node acting as a natural pacemaker. The coronary arteries supply the heart muscle with blood.

Normal function depends on electrical activity and perfusion; disruptions can cause arrhythmias, ischemia, heart failure, and other conditions. Diagnostic methods include electrocardiography (ECG) and echocardiography; advanced imaging such as cardiac MRI may be used to assess structure and function.

In German, Herz is widely used beyond anatomy to express affection or central importance, as in terms of endearment (Herz, mein Herz), or idioms like Herz aus Gold (a heart of gold). The word is also used as a surname.