Sinoatrial node the discovery in a makeshift laboratory set up in a picturesque farmhouse in Kent, England, called Mann's Place. Their discovery was published in 1907. Sinoatrial node The sinoatrial node (SA node), also known as sinus node, is a group of cells located in the wall of the right atrium of the heart. These cells have the ability to spontaneously produce an electrical impulse (action potential; see below for more details), that travels through the heart via the electrical conduction system (see figure 1) causing it to contract. In a healthy heart, the SA node continuously produces action potential, setting the
Sinoatrial node known as a spontaneous Ca spark. This increase in calcium within the cell then activates a sodium-calcium exchanger (NCX), which removes one Ca from the cell, and exchanges it for 3 Na into the cell (therefore removing a charge of +2 from the cell, but allowing a charge of +3 to enter the cell) therefore in-creasing the membrane potential. The calcium is later pumped back into the cell via calcium channels located on the cell membrane and SR membrane. The increase in membrane potential produced by these mechanisms, activates T-type calcium channels and then L-type calcium channels (which open very