How the bladder and the urinary system work

To get a better understanding of some of the reasons behind why people may need to catheterise, we will take a look at how the urinary system works

Everything we eat or drink first goes into the stomach. There it is digested and the blood then transports the nutrients through the body. Anything in the blood that the body no longer needs is sent through the kidneys. They have a very important role. For example, the kidneys communicate to the brain when we feel thirsty and need to drink. They are also a very clever filtering system for the blood. In other words: the kidneys act like a waste-disposal system. Any remaining waste products are removed from the blood. This fluid is called urine and is a mixture of water, salts, toxins and proteins which the kidneys filter out and send through the ureter into the bladder.

The bladder is a hollow organ in the abdomen which stores the urine. The muscles in the bladder wall relax when the bladder is filling with urine and tighten when it’s time to urinate. The bladder wall is lined with layers of transitional cells. Small tubes called ureters take the urine from the kidneys into the bladder. The urine then leaves the bladder through a different tube called the urethra.