Bile salts- Bile last produces from cholesterol. Two types of salts are found in bile- sodium taurocholate and sodium glycocholate. They are being secreted in active form in bile and reach in duodenum along with other biliary secretions. After taking part in the digestion and absorption of fat, most of salts are absorbed again by blood. From where, bile salt returns in liver through hepatic portal system that secretes them again in bile. This cycle of bile salts and other biliary secretions between small intestines and liver is called enterohepatic circulation.
Bile pigments- There are two pigments found in bile- bilirubin and biliverdin. Bilirubin is the main pigment and responsible for yellow color of bile. It is produces by hemoglobing freed from destroyed red blood cells in spleen and bone marrow and reaches in liver through blood. From where, it comes out with bile passing through duodenum. When bilirubin passes through intestines, it is broken in urobilinogen by bacterial enzymes whose most of the part is excreted with fasces in the form of stercobilinogen. This is the reason why the fasces appears in brown or catechu color. The remaining part of urobilinogen is reached again in blood circulatory system after being absorbed and excreted out with urine in the appearance of yellow color. Skin and conjunctiva are become yellow due to collecting extra quantity of bilirubin in extra cellular fluids. This condition is called jaundice. Biliverdin is a green pigment that is produces by oxidizing of bilirubin. There is no any type of affects of bile pigments fall on digestion process.