What Does An Antenna Do For A Radio How Does The Headphone Cord On My Mp3 Player Work As A Radio Antenna?

How does the headphone cord on my mp3 player work as a radio antenna? - what does an antenna do for a radio

My headphone cable FM signals received, but how? It is possible to connect a standard antenna (metal) on my MP3 player in combination, to get better reception? (It has a capacity FM radio, of course.)