The phono cartridge contributes to unwanted noise as well. It is a sound transducer and can be thought of as a specialized type of microphone in that it picks up the vibrations from the stylus as it tracks the record groove and responds to its encoded vibrations.
Unfortunately it can also transmit the vibrations from any noise that it picks up. This includes your footsteps on a wooden floor or any noise including your voice! You can actually record your voice by talking very loudly and very closely to the phono cartridge.