Body Blog 1: The bladder.

Hello. Welcome to my Body Talk blog. I think that the human body is one of the most fascinating subjects on the planet. How everything works together in sync. How it combats illnesses and abnormalities. I want to share my fascination with you. 

So, Topic #1: The Urinary Bladder. 

The bladder is such a fascinating structure. 

It expands (or distends) in size to allow you to hold more waste. The maximum capacity of the bladder is between 800-1000 mL. As the urine accumulates, rugae in the organ flatten out and the walls of the bladder thin. Rugae are fun structures. You can find them in the stomach, too. They are folds in the lining of the organ. 

Now, we get to the part I find most interesting. TRANSITIONAL CELLS. (A.K.A The reason your bladder walls can thin).  Transitional cells form the lining of the bladder and ureters and part of the urethra. 

As the bladder fills and the rugae flatten out, these cells do something amazing. They actually change shape. When the bladder is empty, these cells appear cube or dome like. Once the bladder is full, however, they become flat, irregular, and squamous. The cells also thin from 6 layers down to 3. All of this allows the bladder to store more urine without increasing the internal pressure significantly. 

Cool, huh? I'm keeping this one short and sweet. We'll talk about stuff I'm more versed in next post (like muscles).

Sources. 

Marieb, Mallatt. "23". Human Anatomy (5th ed.). Pearson International. p. 700

Marieb. Human Anatomy and Physiology (6th ed.). Pearson Education, Inc. p. 123-124, 1023-1024

SIU SOM Histology INTRO. Epithelial Study Guide. http://www.siumed.edu/~dking2/intro/epith.htm#trans