Final answer:
Hemoglobin degrades into biliverdin, then into bilirubin, which the liver filters and adds to bile. Bilirubin is later converted to urobilinogen and stercobilin, which is excreted in feces.
Step-by-step explanation:
Hemoglobin degrades into several products during the breakdown of red blood cells. The protein portion, globin, breaks down into amino acids, which the body can reuse. The heme portion undergoes a series of changes: the iron is stored or recycled, while the non-iron part is converted to biliverdin, then reduced to bilirubin. Bilirubin is transported to the liver, bound to albumin, where it is used in bile production.
Excess bilirubin and other metabolites are then filtered by the liver and added to bile. This bilirubin, now in bile, aids in the digestion of fats in the intestines. Eventually, through the actions of intestinal bacteria, bilirubin is converted to urobilinogen and then into stercobilin which is eliminated from the body through feces, providing its characteristic brown color.