Ureteral Peristalsis Simulator

Urine moves from kidney to bladder not by gravity but by active peristalsis: pacemaker cells in the renal calyces trigger a ring of smooth-muscle contraction that closes the ureteral lumen completely and sweeps distally, pumping a discrete bolus ahead of it — the same mechanism as esophageal or intestinal peristalsis. This simulator renders a real 3D ureter whose wall geometry deforms as a traveling contraction wave, with urine boluses carried along by that wave and delivered into the bladder. Tune contraction frequency, amplitude and propagation speed to see how transport rate and peak luminal pressure respond, and push bladder back-pressure past the ureterovesical junction's closing pressure to trigger vesicoureteral reflux — the flap-valve failure behind recurrent pyelonephritis.