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).
The primary purpose of a pacemaker is to maintain an adequate heart rate, either because the heart's natural pacemaker is not fast enough, or because there is a block in the heart's electrical conduction system.ne of the earliest patients to receive this Lucas pacemaker device was a woman in her early 30s in an operation carried out in 1964 at the Radcliffe Infirmary in Oxford by cardiac surgeon Dr Alf Gunning from South Africa and later Professor Gunning who was a student of Dr Christiaan Barnard.