They make up the cardiac pacemaker, that is, the natural pacemaker of the heart. In most humans, the concentration of pacemaker cells in the sinoatrial (SA) node is the natural pacemaker, and the resultant rhythm is a sinus rhythm. Sometimes an ectopic pacemaker sets the pace, if the SA node is damaged or if the electrical conduction system of the heart has problems.
Use IE Tab for Chrome. The best way to use Java (or Silverlight, or other NPAPI-based technologies) going forward is to use IE Tab for Chrome. You can set up Auto URLs to automatically open certain urls using IE Tab, providing a seamless experience, as if Java support never went away. Get it here:
Set which web browsers should use Java. Select which browser installation(s) on your computer should use the latest Java version you installed. Click the Start button on your computer, and click All Programs (on Windows 7) or All apps (on Windows 10). Find Java in the list of programs (which may also say Java (32-bit) or Java (64-bit)).