This study employs micro-computed tomography (micro-CT) to unravel the geometrical intricacies of the rat urinary bladder wall during various states of ex-vivo filling, contrasting markedly with the commonly held idealizations of uniform bladder geometry. Through precise 3D reconstructions at resolutions between 10-20 micrometers, the research meticulously documents the bladder's morphological transformations across different filling pressures. The findings illuminate substantial deviations from the theoretical model of a uniformly thick, spherical bladder, particularly underlined by variations in wall thickness and bladder volume during the transition from voided to filled states. These results are pivotal for refining mechanical models of bladder function, which have traditionally oversimplified the complex geometrical and biomechanical behavior of the bladder. Moreover, this study underscores the potential of micro-CT in providing a deeper understanding of bladder mechanics, essential for advancing therapeutic strategies for conditions like bladder outlet obstruction (BOO), thereby enhancing both surgical and pharmacological treatment paradigms.