The ureters are a pair of muscular, tubular structures responsible for taking urine from the kidneys to the urinary bladder for storage before excretion. They are widest at the renal pelvis and narrow progressively as they enter the urinary bladder. The lining of the ureters is a mucous membrane of transitional epithelium, allowing the organ to stretch and increase its volume depending on fluid pressure.
The temporary storage of urine is the urinary bladder, a hollow organ with distensible walls and is located in the lower abdomen. It is connected to the kidneys by means of the ureters. Like in the ureters, the urinary bladder lining is a mucous membrane of transitional epithelium.