The bladder is a hollow, muscular organ with an inner layer called a urinary epithelium. Two ureters carry urine from the kidney to the bladder. At the lowest point is a urethra, a narrow tube from which urine empties when it’s sphincter muscle releases.
Stones, or calculi, can develop in the bladder when minerals that should be in solution in the urine congeal. The condition is more common in men, and is more commonly found in low-protein diets.
Infection of the bladder (cystitis) is more common in women, with the suspected reason of our shorter urethra providing less of a barrier against bacteria.