ANATOMY

Detailed explanation-1: -The urine flows from the kidneys through the ureters to the bladder. The urine is stored in the bladder until it leaves the body through the urethra.

Detailed explanation-2: -When a person urinates, the pee exits the bladder and goes out of the body through the urethra (pronounced: yoo-REE-thruh), another tube-like structure. The male urethra ends at the tip of the penis; the female urethra ends just above the vaginal opening.

Detailed explanation-3: -When the bladder is full, nerve endings in its wall send messages to the brain. When a person needs to pee, the bladder walls tighten and a ring-like muscle that guards the exit from the bladder to the urethra, called the sphincter (SFINK-tur), relaxes. This lets pee go into the urethra and out of the body.

Detailed explanation-4: -Urine drains from the renal pelvis of each kidney into the ureters. The ureters are long, thin tubes made of smooth muscle. Contractions of the smooth muscle push urine down through the ureters and into the bladder. In adults, the ureters are 25–30 cm long, about the length of a 12-inch ruler.