Cryosurgical apparatus for use in performing ablative surgery; medical devices, namely, cryotherapy and cryosurgical devices, namely, surgical and treatment probes, catheters, endoscopes, and control systems for said cryotherapy and cryosurgical devices, namely, apparatuses for controlling the flow of cryogens, bleeder and pressure reduction valves for maintaining pressure in cryotherapy and cryosurgical devices and delivery systems, rigid and flexible medical endoscopes, catheters, lumen blocking balloons and shields for gastric blocking, nasogastric tubes, suction devices for cryogens removal and endoscopy cameras; cryosurgical tools or units used to destroy tissue during surgical procedures; namely, catheters for the introduction of a cryogen to a target tissue; therapy and surgical delivery systems and components thereof for delivering cryogens to a patient, namely, surgical and treatment probes, catheters and endoscopes; cryosurgical and cryotherapy device control systems, namely, apparatuses for controlling the flow of cryogens, bleeder and pressure reduction valves for maintaining pressure in cryotherapy and cryosurgical devices and delivery systems, rigid and flexible medical endoscopes, catheters, lumen blocking balloons and shields for gastric blocking, nasogastric tubes, suction devices for cryogens removal and endoscopy cameras; therapy and surgical delivery systems and components thereof, namely, apparatuses for controlling the flow of cryogens, bleeder and pressure reduction valves for maintaining pressure in the cryotherapy and cryosurgical devices and delivery systems, rigid and flexible medical endoscopes, catheters, lumen blocking balloons and shields for gastric blocking, nasogastric tubes, suction devices for cryogens removal, endoscopy cameras