What happens when bile cannot enter the second part of the duodenum due to obstruction?

When bile cannot enter the second part of the duodenum due to obstruction, it backs up into the liver and eventually into systemic circulation. This is because bile, produced by the liver and stored in the gallbladder, is directed into the duodenum to aid in the digestion of fats. If there is an obstruction, such as a gallstone or other blockage, the bile will not be able to pass into the intestines.

As a direct result of this obstruction, the accumulated bile can increase pressure in the bile ducts, leading to a backflow of bile into the hepatic duct and then into the bloodstream. This can cause elevated levels of bilirubin in the blood, leading to jaundice and other systemic symptoms.

The other potential processes, such as reabsorption into the bloodstream, elimination through feces, or transformation into urobilinogen, are not what occurs in the case of an obstruction. The bile does not simply get reabsorbed or eliminated through feces during an obstruction, nor does it transform into urobilinogen without the proper flow into the intestines. Instead, the accumulation and subsequent backflow into the bloodstream is the primary consequence of such an obstruction.