Sinoatrial node. The sinoatrial node (SAN; also known as sinus node) is a group of cells located in the wall of the right atrium of the heart.
How Do Web Browsers Work? The World Wide Web is a system of Internet servers that support specially formatted documents. Web browsers are used to make it easy to access the World Wide Web. Browsers are able to display Web pages largely in part to an underlying Web protocol called HyperText Transfer Protocol (HTTP).
The Web browser that is launched when a Web address (URL) is clicked by the user in a non-Web application such as an e-mail client (Outlook, Eudora, etc.). Many users have more than one Web browser and can change the default from one to another as desired.