Question

Conjugated (direct) bilirubin is excreted in bile and metabolized by bacterial flora, producing urobilinogen. What is the role of bacterial flora in the metabolism of bilirubin?

1) Bacterial flora converts bilirubin into urobilinogen
2) Bacterial flora excretes bilirubin in bile
3) Bacterial flora metabolizes urobilinogen
4) Bacterial flora prevents the excretion of bilirubin
5) None of the above

Answer 1

The bacterial flora in the intestine converts conjugated (direct) bilirubin into urobilinogen, which is either turned into stercobilin and excreted in feces or reabsorbed and excreted as urobilin in the urine.

Step-by-step explanation:

The role of the bacterial flora in the metabolism of bilirubin is to convert the conjugated (direct) bilirubin, which is excreted in bile, into urobilinogen. Once bilirubin reaches the intestine, it is transformed into urobilinogen by the action of intestinal bacteria. A portion of this urobilinogen is further converted into stercobilin, which contributes to the brown color of feces, and the remaining urobilinogen can be reabsorbed into the bloodstream and eventually excreted in the urine as urobilin, a yellow pigment.