Gastrointestinal Tract

The Liver

The liver is the largest gland in the body and performs an astonishingly large number of tasks that impact all body systems. One consequence of this complexity is that hepatic disease has widespread effects on virtually all other organ systems. At the risk of losing sight of the forest by focusing on the trees, we will focus on three fundamental roles of the liver:

• Vascular functions, including formation of lymph and the hepatic phagocytic system.
• Metabolic achievements in control of synthesis and utilization of carbohydrates, lipids and proteins.
• Secretory and excretory functions, particularly with respect to the synthesis of secretion of bile.

The latter is the only one of the three that directly affects digestion - the liver, through its biliary tract, secretes bile acids into the small intestine where they assume a critical role in the digestion and absorption of dietary lipids. However, understanding the vascular and metabolic functions of the liver is critical to appreciating the gland as a whole.