What are synchronizing pulses in television?

In the (almost old school) NTSC broadcast standard, there are two "flavors" of sync pulses in the TV signal: vertical and horizontal. Recall that the picture is painted on the screen one line at a time. There are 525 lines to paint, and all the odd ones are painted in one "field" and then all the even lines are painted on in another "field" to create the whole picture. The picture is painted on the screen by the electron beam (the "cathode ray"), and the beam needs to be told which line to paint and when to start painting that given line. The vertical sync pulse sets up the beam for a line, and the horizontal sync pulse tells the beam when to start "painting" that line. Then the next vertical sync pulse will "step the beam down" two lines (remember that it's skipping a line 'cause all odds then all evens are painted), and the horizontal sync pulse will cause the beam to begin its sweep for that line. Two sync pulses - vertical and horizontal. Each one arriving to tell the sweep control circuits what line to paint and when to begin painting it. Piece of cake.