A urodynamic investigation apparatus for receipt of urine from a bladder is provided. The apparatus is characterized by a tubular element, first and second fittings, and a sleeve element, for select passage of urine there through, within the tubular element. The tubular element is characterized by opposing first and second end portions, and a port. The fittings are adapted to be received by the opposing end portions of the tubular element so as to delimit an apparatus chamber. The sleeve element, suspended between the fittings within the chamber, has collapsed and open configurations. The collapsed configuration is indicative of a no urine flow condition, and the open configuration indicative of a urine flow condition, with the sleeve element urine flow condition being a function of pressure applied to the chamber via the port of the tubular element.