Step-by-step explanation:
The arrival of food in the small intestine stimulates the duodenal mucosa to produce the hormones secretin and pancreatin, which in turn stimulate the pancreas to secrete pancreatic juice. Secretin is produced in response to the stimulation of the acidity of the bolus reaching the small intestine. Pancreatic juice, which arrives in the duodenum, is highly rich in bicarbonate and neutralizes the acidity of the bolus and thus guarantees the action of the pancreatic enzymes that only work at slightly alkaline and neutral pH.
Another attachment to the digestive tract is the gallbladder that stores a fluid called bile. Bile emulsifies fats, and is produced by the liver from old red blood cells and is stored in the gallbladder. It has no digestive enzymes. It has bile salts (glycolate and sodium taurocholate) that emulsify fats, facilitating the action of lipases (increase the surface action). Another function of bile salts is to solubilize the final products of lipid digestion, thus facilitating their absorption through the intestinal mucosa.