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: -Urethra. This tube allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra.

Detailed explanation-3: -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.

Detailed explanation-4: -General description. The urethra is the channel that conveys the urine from the bladder to the exterior. In the male it is about 20 centimetres long and carries not only the urine but also the semen and the secretions of the prostate, bulbourethral, and urethral glands.

Detailed explanation-5: -The internal urethral sphincter regulates involuntary control of urine flow from the bladder to the urethra, and the external urethral sphincter provides voluntary control of urine flow from the bladder to the urethra.