Heart Valve

The four valves of connective tissue that support the valve function of the heart. Two of them are sail valves (atrioventricular valves) between atrium, atrium and ventricle, which are attached to the inner heart wall with threads, two of them are so-called pocket valves (semilunar valves), which lead the blood to the lung or into the pulmonary circulation or into the body circulation. Every heartbeat has one of these valves.

https://de.wikipedia.org/wiki/Herzklappe _{(Wikipedia CC-by-sa-3.0)}