The bladder stores pee until an individual is ready to go. Most bladders hold as much liquid as a can and a half of soda. Nerves in the bladder wall tell when it’s time to go. "This super-soft, bright yellow 6" x 4" urinary bladder plush is perfect for telling someone when urine love," Founder Wendy Bryan of I Heart Guts told TDmonthly. Launch date: May 5, 2009.