Final answer:
When red blood cells are destroyed, the liver produces bilirubin from the breakdown of hemoglobin. Bilirubin is then excreted into bile, contributing to its color, and proper processing is essential to avoid conditions like jaundice.
Step-by-step explanation:
When red blood cells (RBCs) are destroyed, the liver plays a key role in breaking down the hemoglobin released from the erythrocytes. This process results in the production of bilirubin, which is eventually excreted in bile and gives it its characteristic yellow color. In the liver, heme from hemoglobin is converted into biliverdin and subsequently into bilirubin. The bilirubin is then released into the bloodstream, where it binds to albumin and is transported back to the liver. Once in the liver, it's conjugated with glucuronic acid to become more water-soluble, forming direct, or conjugated, bilirubin. This soluble form is then added to bile, which is secreted into the intestines to aid in digestion.
Proper functioning of this process is critical; if bilirubin cannot be effectively processed, it may lead to hyperbilirubinemia and jaundice, a yellowing of the skin and eyes. The metabolites of bilirubin elimination, such as stercobilins in the feces and urobilins in the urine, also define the characteristic pigmentation of these excretory products.