01.Head (or headstock): the upper end of the guitar neck, where the tuning machinery is attached.
02.Tuning keys (or tuners, tuning machines): these are rotating pieces of material where the strings are wound around. By turning a tuner, you will wind a string further around, stretching it tighter so that the pitch rises; or by turning in the other direction, you will unwind the string from the tuner causing it to loosen, so that the pitch drops.