Hallux’s Physiology Fix-Up

Professor Hallux gets to grips with physiology!

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Urinary System

The urinary system does a lot of jobs to help our bodies filter out waste. Professor Hallux thinks his Biofiltration Extrapolator might be an improvement.  But can it do everything our urinary system does?

The human body has a great system to get rid of waste.  But Professor Hallux has come up with something to replace mucky trips to the toilet – the Biofiltration Extrapolator, which will filter and rinse everything away. With Nurse Nanobot, they are investigating whether the Biofiltration Extrapolator is better than the real thing, using an online ‘Physiology File


Job 1: Kidneys are kept busy making sure that blood has just the right amount of water in it. They extract water that isn’t needed, along with waste from the bloodstream.  This watery waste is turned into urine – commonly known as wee.

Sadly, Hallux didn’t think about connecting the Biofiltration Extrapolator up to the blood stream!  Systems in the body often need to be connected to other organs and systems in order to carry out their jobs properly.

Job 2: Ureters transport urine from the kidneys to the bladder in two neat tubes.

The Biofiltration Extrapolator is not much more than a sieve, and so water goes everywhere!  Nanobot is after a mop!

Job 3: The bladder’s job is to store urine.  Most of the time you can decide when to wee, and at that time muscles tell the bladder to release the urine. Or muscles can squeeze to stop yourselves from weeing until you get to a toilet.

Well, no control mechanism at all on the Biofiltration Extrapolator?

Job 4: The Urethra carries urine from the bladder to the outside of the body. Because its opening is very small, it’s normally easy to wee without making a big mess.

It’s a major physiological failure – unless you want your toilet two foot deep in wee.

Hallux’s fun facts about the urinary system

  • Each kidney has about 1,000,000 filtering units, called nephrons.
  • Every 45 minutes, your whole blood supply passes through your
  • Roughly 40 gallons of blood in women and 48 gallons of blood in men are filtered each day.
  • The colour of your urine can reflect if you are drinking enough water; it is usually light yellow if you are drinking enough water and dark yellow if you are not.
  • For someone with kidney failure, it typically takes 4 hours of dialysis, 3 times a week to perform the filtering duties of normal kidneys.
  • The need to urinate is felt when about 1 cup of urine fills the bladder.

Want to find out more about the urinary system? Click here to Professor Hallux builds a Body

Physiology is fundamental! It not only helps us understand the jobs parts of the body have to do and how they do them.  It also means we can understand the effect other things have on bodies.

Join Professor Hallux as he looks at each part to see what fixes he can make to build a better body!

You can hear Hallux’s Physiology Fix-Up weekdays from 5pm on Fun Kids!

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Hallux’s Physiology Fix-Up with support from The Physiological Society.


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Hallux’s Physiology Fix-Up

Professor Hallux gets to grips with physiology!

More From Hallux’s Physiology Fix-Up