How Does Your Body Make Pee? Urinary System Anatomy and How It Works

Pee is your body’s way of extra rid of extra fluid, so your body doesn’t puff up with water. Your body makes pee to get rid of waste, too! So how does your body make pee? This job belongs to the urinary system – your body’s way of making urine, the scientific name for pee.

Parts of the Urinary Tract

Let’s follow the path of pee! Along the way, we’ll meet the key players of the urinary tract team.

Urinary System Anatomy Diagram with Labels

Kidneys

Your kidneys are like cleaning stations for your blood. This pair of bean-shaped organs are located in your lower back. Most people have 2 kidneys, but some people have one kidney that does all the work.

Blood flows through each kidney, kind of like how cars drive through a car wash to get rid of dirt and gunk.

Inside the kidney cleaning station are millions of tiny tubes called nephrons. These nephrons filter your blood and flush out toxins and extra fluid. But the nephrons need to keep the good stuff. While while filtering out waste, nephrons need to keep nutrients like protein and sugar in your blood.

Then, the leftover liquid becomes urine (pee), which then flows down the ureters.

kidney nephron anatomy - labeled

Ureters

Just as your sinks and toilets drain into pipes, your body has tubes called ureters that collect urine.

The right ureter connects the right kidney to the bladder, while the left ureter connects the left kidney to the bladder.

In adults, each ureter is around 8 to 10 inches long – just a little shorter than a ruler!

Bladder

Then, urine drips into the bladder, which is muscular, pear-shaped organ is located at the bottom of your belly. The bladder acts like a storage container that we empty out when we pee.

Depending on how often you go to the bathroom, your urine can hang out in the bladder for a while! To make room for more urine, your bladder needs to stretch and get bigger. When you go to the bathroom, the bladder squeezes urine out of your body.

Usually, the bladder goes back to its regular size after you pee. But if you make a habit of holding your pee too long instead of letting it out, your bladder muscles can get weak and stretched out. When the bladder muscles are weak, urine can leak out—oops!

So, as the saying goes, when you gotta go, you gotta go!

Urethra

Whew! Urine is just about to cross the finish line!

Urine needs to flow through one more tunnel, a tube called the urethra. The urethra’s job is to carry urine from the bladder out the body.

But not so fast!

At the end of the urethra, you have a sphincter muscle that you can control. When you are holding in your pee, the sphincter is closed. When you decide to pee, or when you just can’t hold it anymore, the sphincter opens.

How the Bladder Fills Up and Empties (Video)

Watch urine flow into the bladder. When the bladder feels full, it will squeeze urine out the urethra!

Why Do Some People Rush to Pee?

Sometimes the urge can come on fast! Have you heard of these common causes of rushing to the bathroom?

  • A large, hard stool can put pressure on the bladder. This is what happens to constipated kids and grown-ups.
  • In pregnant women, a growing baby can put a lot of weight on the bladder.

Roadblocks: When Urine Can’t Get Through the Ureters or Urethra

In some people, the ureters or urethra might not fully develop.

In other people, a kidney stone or cancer could block the ureters.

Anytime a tube is block, a person can have pain and problems with urinating.

  • WIPE CAREFULLYBecause the urethra is close to the anus, bacteria from poop can make its way to the wrong hole. Sometimes, the bacteria can cause a bladder infection. This is why we wipe our bottoms from front to back.
  • WATER IS YOUR FRIEND – Drink water when you are thirsty, especially if you have been sweating or playing sports. Hydration helps your body make urine and prevents constipation.
  • WELCOME BATHROOM BREAKS – Listen to your body and go to the bathroom when you feel the urge to pee.

Learn More About Your Body


Updated on August 27, 2022 Reviewed by Betty Choi, MD

Updated on August 27, 2022

Reviewed by Betty Choi, MD