What chemical does digestion release that makes you happy

There are number of neurotransmitter which are released by the various glands and ducts, as this secretion of the chemical is well regulated by the over all brain, and nervous system inside the human body. While, the stomach itself has a number of cells and epithelial layers which are there for the secretion of the different level of chemicals inside the body and the stomach for better process of digestion or processing of the ingested food.As, for the satisfaction of the different cells and receptors inside the body there are a number of secretary bodies for the availability of the different chemical inside the body and having a proper mechanisms.The hypothalamus is some times refereed to as the regulatory body for the human body. And that is also due to the secretions which happens on its command inside the human body.The dopamine is one of these neurotransmitters which are released on the activation of the hypothalamus inside the human body. As, the presence of the chemical brings great stability to the over all system of the human body, as it brings more calmness to the body.                                                                                                          

Cells of an organism tell each other when predators are near.