Implantable pump apparatuses

An implantable, miniature pump assembly having a flexible elastic bladder actuating assembly. The bladder, in the non-flexed state, has an elongated, substantially rectangular profile, with a predetermined internal volume or capacity. Influent and effluent conduits extend in opposite directions from respective end portions of the bladder. Each of the conduits include one way valves disposed therein to limit fluid flow to a single direction into and through the bladder. Contraction and expansion of the bladder by means of energy harvested from the dynamic environment in which it is implanted in response to ambient random dynamic motion creates alternating pressure and vacuum within the bladder, alternately drawing fluid into the bladder through the influent conduit, and forcing fluid from the bladder via the effluent conduit. The bladder pump assembly harvests its operational energy from the random dynamic motion of the surrounding organs and tissues and therefore does not require an internal or external power source.