from The Century Dictionary.
- noun The brown coloring matter of the feces.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Physiol. Chem.) A coloring matter found in the fæces, a product of the alteration of the bile pigments in the intestinal canal, -- identical with
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun biochemistry A
tetrapyrrolic bile pigment, one of the end productsof heme catabolism, responsible for the brown colour of human faeces.
Sorry, no etymologies found.
As the article says, the bilirubin goes into the bile and breaks down in your GI tract to stercobilin, which is brown.
It's a precursor of stercobilin, which is to say ... same shit.
I'm no dr. of scatology or anything, but I had my gallbladder removed several years ago, and by this explaination also the processes that make the brown-coloring bile and stercobilin.
Yep, my sources for The Re/Search Guide to Bodily Fluids said it was yellow bilirubin, which turns brown -- so if bilirubin is a precursor to brown stercobilin, that all makes sense.
So while brown stercobilin, red phycoerythrin, green phycoverdin, and blue phycocyanin all have similar structures with lots of alternating bonds, the differences in color aren't necessarily closely tied to any one part of their structure.
"[Bile is] metabolized by the bacteria in your large intestine, leaving behind a byproduct called stercobilin — and it's that stercobilin that gives stool a brown pigment."
Maybe spgarbet wants an explanation that accounts for the brown color of stercobilin?
"It's metabolized by the bacteria in your large intestine, leaving behind a byproduct called stercobilin — and it's that stercobilin that gives stool a brown pigment."
Without stercobilin, your poo would actually be a sort of pale, off-grey color, like white clay.