This is the beginning of the small intestines, and it empties the stomach. It is 9 or 10 inches long, holds about the same amount of food as the digestive antrum or bottom of the stomach, and, through a papilla or sphincter, squirts a mixture of bile and pancreatic juices onto the previous stomach contents. These juices neutralize the acidic chyme; the pancreatic alkali and bile acids form soap to emulsify and aid fat digestion; and the duodenum walls secrete additional fluids and enzymes to admix with the pancreatic enzymes to initiate the final upper digestive investment. The duodenal wall secretes blood hormones to excite the brain, and gallbladder and pancreas secretions, and, if overwhelmed, can inhibit the stomach from sending anything else down for a while, until they can catch all their collective breath.