ScribePost: Introduction of Urinary System (May 5)

Ok so today we started off with a pop quiz which was on the bolded words and the funtions of the urinary system found in 16.1 which is pages 304 to the top of 306

Functions of the Urinary System

- there are 4

Excretion of Metabolic Wastes
- this is the toxins leaving your body (nitrogenous wastes).
We started talking about survivorman and how you need to filter your pee before you can drink it if you ever happen to need to hydrate yourself and don't have water. For those of you not in physics who have not seen this video it's about a waterbottle which can filter out anything that is not smaller then 15 nm (nanometers). It's being used in third world countries so maybe an idea for St Mary's mission next year? Anyways here's the video if you want to check it out



Maitenance of Water-Salt Balance
-too much water = higher blood pressure = micturition

Maitenance of Acid-Base Balance
- excrete hydrogen ions but keep bicarbonate ions to make acid (which is why urine has a pH of 6 or lower)

Secretion of Hormones
-renin and erythropoetin

It was asked if high blood pressure caused a person to urinate more often so I researched it and there are no symptoms I could find on any medical website that said that urination occurred more often

Here is a diagram of the Urinary system similar to the one that's found in our textbook (page 305)

The 4 main organs are

1. Kidneys
2. Ureters
3. Urinary Bladder
4. Urethra

What I found most interesting in class was about the kidney stones. A kidney stone is a build up of iodine crystals which block the urethra causing you not to be able to pee and causes pressure on your bladder. You might remember a certain friends episode...

As Joey showed us it is very painful to pass kidney stones so I thought it would be good to get some prevention tips

Lastly we learnt about the actual urination.

1. stretch receptors in wall of bladder expand
2. it can hold up to 250 ml of urine
3. motor impulse from spinal cord causes contraction
4. micturition reflex occurs

The reflex is controlled more as we reach adulthood but as Mr Mac said with the dumbell analogy you can only hold your pee for so long.

The power point goes into more detail but as of late is not yet up on the downloads page so keep checking.

We're discussing the Nephron next class which FOR SURE is going to be on the exam either a long or short answer so make sure you pay attention next class. If you want a head start the reading of it starts on page 306 and its a couple pages of reading.