Understand your urinary system – how does the bladder work?

Image of lady holding a cup. The bladder is a hollow organ that stores urine until it can be conveniently expelled from the body. The bladder's walls expand to store urine and then contract and flatten to empty urine through the urethra.

MS and the bladder

When living with MS it is common to experience some form of bladder issue during your life. This is because MS causes nerve damage in the areas of your brain and spinal cord that play important roles in the functioning of your bladder.1

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The bladder is a part of the urinary system – a controlled network of nerves that connect the brain and bladder via the spinal column. This is a complex system that is made up of lots of different parts. Let’s dive in.

What parts make up the urinary system?

  • The kidneys filter impurities and water from the blood and produce urine.1
  • The ureters are thin tubes that carry urine from the kidneys to the bladder.1 
  • The bladder is an elastic sac that stores the urine until it is ready to be expelled from the body.1 
  • The destrusor muscle (the bladder wall) contracts to push urine out of the bladder.1
  • The sphincters are circular bands of muscles that act like valves and can open and contract to control the flow of urine out of the bladder.1
  • The urethra is the tube that carries urine from the bladder to the outside of the body.1
Storing urine

Storing urine

The bladder is a hollow organ that stores urine until it can be expelled from the body. The bladder's walls expand to store urine and then contract and flatten to empty urine through the urethra.2

As the bladder fills, nerve signals are sent to your brain and trigger the need to urinate. Put simply, this is the feeling of needing to go to the toilet.

Releasing urine

Releasing urine

When you are about to urinate, the nerve signals coordinate for the detrusor muscle to tighten which will squeeze urine out of the bladder while the pelvic floor muscles and urinary sphincter muscles relax. This allows urine to leave the bladder through the urethra. When these signals are coordinated, normal urination happen.2

How can MS affect the bladder?

You can think of your bladder as a light, and your brain as a switch. Your nerves are like the electric cable that connects the switch to the light and tells the light when to turn on. The electric cable is protected by a plastic coating, just like how myelin protects your nerves.  
 
If the cable’s coating deteriorates, the light might not behave as expected when you flip the switch. This is like how MS can damage the myelin protecting your nerves and garble the signals between your brain and bladder, leading to bladder dysfunctions.1

Why do bladder dysfunctions matter?

Recognising your bladder issues and seeking support can help to improve your quality of life when living with MS. If your bladder functions are impaired, the risk of contracting a bladder infection  increases,3,4,5 which may further exacerbate MS.6 Therefore, reflecting on your bladder's behaviour is the first step to ensuring your circuitry is working properly and you are in control of when you turn the light on and off.

‎Take the MS bladder check

You can use our MS bladder check to reflect on any current bladder-related symptoms of your MS. This may be the first step to recognising your symptoms and opening up this discussion with your MS nurse or doctor.