A pressure regulation system for discharging a liquid having a predetermined liquid pressure from a liquid opening, including an elastic bag having a liquid phase and a gas phase, where the liquid opening in an operational position of the elastic bag is formed in the lower area of the elastic bag, at least two push elements, at least one drive unit and a control unit. The elastic bag has a gas opening, which extends into the gas phase. The pressure regulation system has a ventilation unit, which is connected to the control unit for communication and which connects to the gas opening of the elastic bag. The ventilation unit regulates the liquid pressure of the liquid discharged through the liquid opening by means of a gas supply into the elastic bag and/or a gas discharge from the elastic bag.