 Dear students, in this topic we shall discuss the gastrointestinal secretions. The gastrointestinal secretions include both endocrine as well as exocrine secretions. Elementary canal is generally described as the largest endocrine and exocrine gland of the body. First we shall discuss the endocrine secretions of gastrointestinal tract. The gastrointestinal tract has many entero endocrine cells which are spread throughout the digestive tract for example in the stomach, in the pancreas and in the small intestine which produce various hormones. The entero endocrine cells produce gastrointestinal hormones which are liberated directly into the bloodstream. These hormones are related to the functions of gastrointestinal tract so they act on the tissues of gastrointestinal tract or gut and control various functions related to the digestion or absorption of food. The various gastrointestinal hormones include gastrine, cholecystoquinine, sacritin, glucagon, vasoactive intestinal peptide VIP, gastric inhibitory peptide GIP, somatostatin, motiline and substance P. Apart from these, another hormone is Gryline which is a peptide hormone and is released from liver and stomach. This hormone is known as a refer to as hunger hormone. The fasting individuals have a higher quantity or level of this hormone. Now we shall discuss the exocrine secretions of the gastrointestinal tract. The exocrine tissues which produce exocrine secretions include sliver glands, many secretory cells of stomach and intestinal epithelium, the secretory cells of liver and pancreas. The human gastrointestinal tract secretes about 7 liters of exocrine fluids in a day. These exocrine secretions have varied compositions but all have some basic components that is most of them contain enzymes, all of them contain huge quantities of water, mucus, inorganic ions, or salts and various ions. Now we shall discuss the digestive enzymes which are present in the exocrine secretions. These enzymes belong to three major categories. These enzymes may be Proteases or Carbohydrates and are Lipases. These three categories correspond to the three major types of foodstuffs which require hydrolysis or breakdown. In three major categories, there are certain specialized enzymes found in some exocrine secretions. They break or digest specific components of the food. For example, enzymes for hydrolysis of nucleic acids and nucleic acid residues. These enzymes are Nucleases, Nucleotidases and Nucleosidases. The other special enzymes are Asterases which break down the esters present in ripe fruits.