Gastric (Digestive) Juices

Digestive Juices - colorless, watery, acidic, digestive fluid secreted by the stomach glands.

There are many types of different juices secreted by many organs within the digestive tract. In general, the juices have digestive enzymes and other chemicals that aid digestion, and help the nutrient absorption from the food.

The gastric juice is a mixture of enzymes

• Hydrochloric acid
• Mucin
• Pepsin (works on proteins and fats)
• Rennin (curdles milk into casein clot)

Small amounts of gastric juice are present in the resting state. The anticipation of food, or its entry into the mouth, excites a reflex or conditioned secretion. Much more gastric juice is formed when food actually enters the stomach. This process may take from one to five hours.

Hormones in Digestion: Gastrin

The stimulus to secretion is not mere contact with food but a hormone, gastrin. Protein, alcohol, and coffee are potent catalysts of this phase of secretion. The secretion is strongly acidic.

The acid alone is responsible for minor breakdown of certain foods, but most of the work is done by the pepsin, which also helps liberate the fat of the food, preparing it for digestion in the duodenum.