TortoiseGit difference between Fetch and Remote Update

In the TortoiseGit application, in the "Git Sync..." dialog there is a drop down box with different options. I tried to figure out the difference between Fetch and Remote Update:

 I found this good answer on StackOverflow: http://stackoverflow.com/questions/2688251/what-is-the-difference-between-git-fetch-origin-and-git-remote-update-origin.