A system for distending body tissue cavities of subjects by continuous flow irrigation during endoscopic procedures, the system comprising: a fluid source reservoir containing a physiologic fluid meant for cavity distension; an outlet port of the fluid source reservoir being connectable to an inflow port of an endoscope instrument via an inflow tube for dispensing the fluid at a controlled flow rate into the cavity, the flow rate at which the fluid enters into the cavity being termed as the cavity inflow rate; an inflow pressure transducer being located anywhere in the inflow tube for measuring the fluid pressure inside the cavity, an outflow port of the endoscope being connectable to an inlet end of a variable speed positive displacement outflow pump through an outflow tube for removing the fluid from the cavity at a controlled flow rate, the flow rate of the outflow pump being termed as the cavity outflow rate, and an outlet end of the outflow pump being connected to a waste fluid collecting container through a waste fluid carrying tube, the fluid source reservoir comprising a hollow barrel for holding the fluid, a plunger mechanism mounted slidably inside the hollow barrel for dispensing the fluid and the plunger mechanism being provided with an electromagnetic means comprising a coil wound around a magnetic rod that slidably moves the plunger mechanism in a to and fro direction inside the hollow barrel, characterised in that the system further comprises an inflow housing tube having a controllable constriction site, a distal end of the same being connected to the inflow tube to provide an exit route for any excess fluid present inside the tissue cavity or being dispensed by the fluid source reservoir, thereby minimizing turbulence inside the body tissue cavity and maintaining the body tissue cavity pressure at a stable value despite physiological contractions of the body tissue cavity wall. a fluid source reservoir containing a physiologic fluid meant for cavity distension; an outlet port of the fluid source reservoir being connectable to an inflow port of an endoscope instrument via an inflow tube for dispensing the fluid at a controlled flow rate into the cavity, the flow rate at which the fluid enters into the cavity being termed as the cavity inflow rate; an inflow pressure transducer being located anywhere in the inflow tube for measuring the fluid pressure inside the cavity, an outflow port of the endoscope being connectable to an inlet end of a variable speed positive displacement outflow pump through an outflow tube for removing the fluid from the cavity at a controlled flow rate, the flow rate of the outflow pump being termed as the cavity outflow rate, and an outlet end of the outflow pump being connected to a waste fluid collecting container through a waste fluid carrying tube, the fluid source reservoir comprising a hollow barrel for holding the fluid, a plunger mechanism mounted slidably inside the hollow barrel for dispensing the fluid and the plunger mechanism being provided with an electromagnetic means comprising a coil wound around a magnetic rod that slidably moves the plunger mechanism in a to and fro direction inside the hollow barrel, characterised in that the system further comprises an inflow housing tube having a controllable constriction site, a distal end of the same being connected to the inflow tube to provide an exit route for any excess fluid present inside the tissue cavity or being dispensed by the fluid source reservoir, thereby minimizing turbulence inside the body tissue cavity and maintaining the body tissue cavity pressure at a stable value despite physiological contractions of the body tissue cavity wall.