Question 4#

With respect to the enterohepatic circulation ofbile, where are the majority of bile salts reabsorbed?

a. Duodenum
b. Proximal jejunum
c. Terminal ileum
d. Colon

Correct Answer is C


Bile salts are sodium and potassium salts of bile acids derived from cholesterol by hepatocytes. After synthesis, the primary bile acids cholic and chenodeoxycholic acid are conjugated to either taurine or glycine and then secreted into the biliary system. Approximately 90 to 95% of these primary bile salts and acids are absorbed by active transport at the terminal ileum, while the remainder enter the colon and are converted to secondary bile acids (deoxycholic and lithocholic acids) and their associated salts by resident bacteria. Bile acids and salts reabsorbed in the terminal ileum are reabsorbed through the portal circulation, while those lost in the stool are replaced by hepatic synthesis.