Digestive Juices

The digestive system contains numerous organs that contribute to the secretion of digestive juices

  • These organs include the salivary glands, stomach, liver, pancreas and small intestine

Organs Involved in Digestive Juice Production

digestive juice organs

Salivary Glands

  • Initiate chemical digestion while food is still being physically chewed within the mouth
  • Secretes salivary amylase, which assists in the breakdown of glucose polymers (e.g. starch)


  • Produces stomach acids which aid in the chemical breakdown of food materials
  • Secretes proteases to function as the initial site of protein digestion
  • Stomach proteases typically require acid conditions for activation (e.g. pepsinogen → pepsin)


  • Produces bile which is responsible for the emulsification of fats (separates fats globules to enhance lipase activity)
  • Bile produced in the liver is commonly stored in the gall bladder until release


  • Secretes bicarbonate ions into the duodenum to neutralise stomach acids (intestine pH is usually ~ 7 – 8)
  • Also secretes lipase (for fat digestion), amylase (for carbohydrate digestion) and protease (for protein digestion)
  • Pancreatic proteases are activated by enzymes and not by acid conditions (enterokinase converts trypsinogen to trypsin)

Small Intestine

  • Intestinal juices are secreted from pits called crypts of Leiberkuhn, located between intestinal villi 
  • Digestive enzymes in the small intestine are typically immobilised on the epithelial membrane (e.g. maltase)
  • This prevents the enzymes from being removed from the body as part of the normal digestive cycle
  • It also concentrates the digestive products at sites where membrane proteins are present (to optimise absorption)