Electrons are negative. The anode is positive, so it attracts the electrons pouring off the cathode. In a TV's cathode ray tube, the stream of electrons is focused by a focusing anode into a tight beam and then accelerated by an accelerating anode. This tight, high-speed beam of electrons flies through the vacuum in the tube and hits the flat screen at the other end of the tube. This screen is coated with phosphor, which glows when struck by the beam.
voltage is basically the difference in the amount of electrons between two ummm... things, they could be anything really (unless they don't allow much flow of electrons if any, like rubber). but for electricity to move, the electrons must be attracted to something. in a thing with not many electrons, electrons in abundance from another thing will flow more readily towards it.
anyway, this is a pretty poor explanation, but what I'm basically saying is that, the more voltage, the more electrons are attracted to the screen. and that's how the monitor can be quite bright.
did you know static electricity can be thousands of volts?