8th February 2024

Overview

The pancreas’ primary secretion consists of high volume, isotonic, alkalotic fluid due to high concentration of HCO3- to neutralise the acidic chyme from the stomach. This also contains digestive enzymes for protein, carbohydrate, and fat (protease, amylase, and lipase). 

The acinar and ductal cells of the pancreas perform the exocrine function of the pancreas. Acinar cells secrete fluids rich in enzymes and electrolytes. Ductal cells modify the fluids by producing water and electrolytes. The islet cells perform the endocrine function of the pancreas ( see Endocrinology section for more details). 

Both gastric and intestinal stimuli stimulate the secretion of the pancreatic juices. Gastrin from the stomach stimulates enzyme secretion from the acinar cells. Intestinal hormones are stimulated by peptides, amino acids, fatty acids and H+ within the duodenum, and the main hormones involved are secretin and CCK. Secretin will stimulate the secretion of bicarbonate, while CCK will stimulate the secretion of enzyme secretions. 

Image Source: Wikimedia Commons (2013). Exocrine and Endocrine Pancreas, Licensed under a creative commons licence. Available for free at: https://upload.wikimedia.org/wikipedia/commons/a/ac/2424_Exocrine_and_Endocrine_Pancreas.jpg  (Accessed: 4 January 2024).