Pacemaker current on hyperpolarization, and very slow kinetics. The funny current is highly expressed in spontaneously active cardiac regions, such as the sinoatrial node (SAN, the natural pacemaker region), the atrioventricular node (AVN) and the Purkinje fibres of conduction tissue. The funny current is a mixed sodium–potassium current that activates upon hyperpolarization at voltages in the diastolic range (normally from −60/−70 mV to −40 mV). When, at the end of a sinoatrial action potential, the membrane repolarizes below the I threshold (about −40/−50 mV), the funny current is activated and supplies inward current, which is responsible for starting the diastolic depolarization phase
Lunar node about 0.94901 Gregorian year, as do descending-node eclipses. The nodes are called by different names in different areas of the world. In ancient European texts, the ascending node is referred to as the dragon's head ("Caput Draconis", or "Anabibazon"). Its symbol is , the astronomical and astrological symbol for the dragon's head. By the same analogy, the descending node is also known as the dragon's tail ("Cauda Draconis", or "Catabibazon"), and its symbol is the inversion of that of the ascending node: . In Hindu astronomy, the ascending node ☊ is called "Rahu" and the descending node ☋ is called