Understanding the Urinary System

If you've been diagnosed with a neurogenic bladder disorder, it helps to learn some basic information about how your body works. Learn about your urinary system here.

Get information about your body's urinary system.

Gaining knowledge about how your body works is always a good step when you’re diagnosed with a medical condition. If you’ve recently learned that you have a neurogenic bladder, here is a helpful primer on your urinary system. 

Urinary system anatomy

Your urinary system is made up of the kidneys, ureters, bladder, urethra, internal and external sphincters and muscles. All have their unique role in the filtering process.

Kidneys filter extra water and certain waste products from the blood to make urine. Kidneys typically produce 30-80ml of urine each hour. Urine is carried from the kidneys through tubes called ureters to the bladder, where it is temporarily stored until you urinate.

Ureters are about 28-36cm long in adults. They are designed to keep urine from flowing back up to the kidneys. Muscular contractions in the ureters push urine down from the kidneys to the bladder.

The bladder is a hollow organ with a muscular wall and two primary functions – the storage and emptying of urine. In a relaxed state, the adult bladder can hold about 480mls of urine before you feel a strong urge to urinate. Bladder size, shape and capacity to store urine are different for each person. 

The urethra is the tube that carries urine from the bladder out of the body. It is a muscular tube lined with a mucous membrane with an opening at the end. 

Sphincters are two ring-like muscles (called the internal and external sphincters) that surround the urethra. The external sphincter is the one that is voluntarily contracted to control when you urinate. 

Muscle contraction, both voluntary and involuntary, is involved in urination. Bladder muscles contract and the sphincters open. Pelvic floor muscles are made up of several small muscle groups that surround the urethra, vagina (in women), and rectum. They provide support to the organs of the pelvis and they help hold the urethra in place.

The role of your nervous system

The process of urination involves coordination between the bladder, the sphincter muscles and an intact nervous system. A healthy functioning nervous system and brain are very important for proper coordination of this complex process, which can be simplified into three steps: 

1. When the bladder is full, nerve impulses are sent to the lower portion of the spinal cord
2. These impulses then travel to the brain to communicate that the bladder is full
3. The brain sends a message to the bladder, telling it to contract in order to release the urine. 

Differences between male and female urinary systems

Most of the urinary system is similar between men and women, with the key difference being the urethra exit tubes, as well as some of the gender-specific issues that may arise.

The more you know about your body’s urinary system and neurogenic bladder disorder, the more in control you’ll feel as you work with your healthcare team to treat and manage this condition.