Question

all digestive juices are secreted by cells in the stomach and small intestine

Answer 1

In stomach, Digestive enzymes namely - HCl, Pepsin and Mucus are secreted by gastric glands present in the inner lining of the stomach wall. HCl ( Hydrochloric acid) helps to make food acidic, which activates Pepsin ( an inactive enzyme). Pepsin is an enzyme which helps in the digestion of proteins. Proteins aren't fully digested here. But they break down into simpler ones. HCl also kills all the germs in the food. Mucus prevents HCl to damage stomach as HCl is concentrated. Now, Food moves to Small Intestine. In small intestine, Bile Juice from liver helps to convert big fat molecules into smaller ones for their easy digestion (Fat Emulsification). Pancreatic Juices which consist of Lipase, Trypsin. Lipase digest emuslsified fats and Trypsin digest proteins, finally converting them into Amino Acids. Carbohydrates also are digested here. Here, Digestion ends.