Mounds in the water form in areas where the water meets land, where water is warmer, or where two currents converge. Gravity then pushes this water down slope on the mounds and creates currents. Deep water currents, also called thermohaline circulation, are found below 400 meters and make up about 90% of the ocean. Like surface currents, gravity plays a role in the creation of deep water currents but these are mainly caused by density differences in the water.
The pacemaker of the heart is a bundle of cells that tells the  heart when to beat. These cells are connected to the rest of the  cells of the heart and communicate with theâ¦m through electrical  signals. The pacemaker cells set the pace (or rate) of the  heartbeat.    The actual structure that serves as the heart's primary pacemaker  is called the sinoatrial node (SA node).
A pacemaker is a small device that's placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate. Pacemakers are used to treat arrhythmias (ah-RITH-me-ahs). Arrhythmias are problems with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.