THE PHYSIOLOGICAL ROLES OF THE LIVER AND PANCREAS: INTEGRATED FUNCTIONS IN METABOLISM AND HOMEOSTASIS

The liver and pancreas are vital organs that perform complementary and interconnected physiological functions essential for maintaining metabolic homeostasis, digestion, and overall health. This comprehensive review examines the multifaceted physiological roles of these organs, their structural organization, functional integration, and clinical significance. The liver, weighing approximately 1.5 kg in adults, serves as the body's primary metabolic factory, performing over 500 distinct biochemical functions including carbohydrate, protein, and lipid metabolism; detoxification of xenobiotics and endogenous compounds; synthesis of plasma proteins and clotting factors; bile production and secretion; storage of vitamins and minerals; and immunological functions. The pancreas functions as both an exocrine gland, producing 1.5-3.0 liters of pancreatic juice daily containing digestive enzymes, and an endocrine gland, secreting hormones that regulate glucose homeostasis. Our analysis reveals that hepatocytes constitute 60-80% of liver mass and perform most metabolic functions, while the pancreatic acinar cells produce digestive enzymes and islets of Langerhans secrete insulin, glucagon, and other regulatory hormones. The liver processes approximately 1.5 liters of blood per minute, metabolizing nutrients absorbed from the gastrointestinal tract and maintaining blood glucose levels between 70-100 mg/dL through glycogenolysis and gluconeogenesis. The pancreas secretes 15-20 grams of digestive enzymes daily and maintains glucose homeostasis through precise insulin and glucagon secretion. Dysfunction of these organs results in serious pathological conditions including hepatic cirrhosis, fatty liver disease, diabetes mellitus, pancreatitis, and metabolic disorders affecting millions worldwide. This review synthesizes current understanding of liver and pancreas physiology and discusses implications for health, disease prevention, and therapeutic interventions.