How do the inner wall of …

The inner walls of the stomach and small intestine and the various glands  such secrete  digestive juices as salivary glands, various other glands and liver and pancreas. Salivary glands secrete salivary amylase enzyme. The liver is essentially an exocrine gland, secreting bile into the intestine. But, the liver is also an endocrine gland and a blood filter. The liver has a diversity of functions not typically associated with glands. The liver is a metabolic factory, synthesizing and breaking down a variety of substances. The pancreas is a glandular organ in the digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity behind the stomach. It is an endocrine gland producing several important hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide which circulate in the blood.