Q: What are the basic parts of the urinary system?

A: The urinary system is made up of the kidneys, the ureters, the bladder, and the urethra.

Q: What role do the kidneys have in the urinary system?

A: There are two kidneys each about 4 inches long located along side the backbone and below the lungs.

The kidneys are continually filtering the blood and removing waste products from the bloodstream.

They also regulate the amount of salt and water in the blood stream by varying the concentration of the urine.

The kidneys pass waste and water as urine into the ureters that connect the kidney to the bladder.

Q: What role do ureters have in the urinary system?

A: The ureters are tubes that collect the urine and pass it to the bladder.

At the point where the ureter is attached to the bladder there is a one way valve that lets the urine pass into the bladder but not from the bladder back into the ureter.

Q: What role does the bladder have in the urinary system?

A: The bladder is a muscular sac that when relaxed stores urine and when it contracts pushes the urine out of the bladder into the urethra.

Normally a bladder will hold about 1 and one half cups of urine before it begins feeling pretty full.

Q: What role does the urethra have in the urinary system?

A: The urethra is a tube that runs from the bladder to the opening on the penis.

Before it gets to the penis it passes through the prostate gland and is joined by tubes from the testicles that carry sperm to the urethra.

Q: How is the bladder controlled?

A: Control of the bladder and emptying at the desired time is a function of the nerves and spinal cord.

Small nerves run to and from the spinal cord and the bladder.

Some carry information about how full the bladder is.

Others keep the muscles of the bladder wall relaxed.

Still others cause the muscles of the bladder wall to contract.

The balance between these nerves is controlled by connections that run through the spinal cord to the brain.


When a person feels the bladder needs emptying they go to the bathroom and prepare themselves to empty the bladder.

When they are ready, the brain sends a signal for the bladder relaxing to stop and for the bladder contracting muscle to squeeze.

At the same time the outlet from the bladder to the urethra is signalled to relax and the urine flows out of the body through the urethra.

Q:I have heard about reflexic and arreflexic bladders. What is the difference between arreflexic and reflexic bladder?

A: People with arreflexic bladders have injuries to the nerves that connect the bladder to the spinal cord.

People with reflexic bladders have injuries to the spinal cord.

People with arreflexic bladders have fewer options about how to manage the bladder.

They also rarely have problems with bladder sphincter dysynergia.


Your physician will be able to tell you what kind of bladder you have.

Sometimes a test called cystometrics is required to be sure.