 Dear students, in this topic we shall discuss the various mechanisms which control the motility of elementary canal. The motility of elementary canal involves coordinated contractions of circular and longitudinal smooth muscle layers of the elementary canal. This coordination is coordinated or regulated by a combination of intrinsic mechanisms and extrinsic mechanisms. First we shall discuss in detail the intrinsic mechanisms which are dependent on the intrinsic myogenic properties of the smooth muscles of the gut. As the smooth muscles of the gut are myogenic, they are capable of producing an intrinsic cycle of electrical activity. This leads to muscle contraction without any involvement of external neural stimulation. If these muscles do not receive a message from the central nervous system, then they generate their own electrical activity. The intrinsic cycle occurs due to the rhythmic depolarization and repolarization of the cells of smooth muscles of the digestive tract. This rhythm is known as basic electrical rhythm or BER. BER involves spontaneous slow waves of depolarization. These waves progress slowly along the muscle layer. Some of these slow waves give rise to action potentials due to inward flow of calcium grunt. These calcium grunts lead to contractions of smooth muscle cells. Dear students, the amplitude of slow wave basic electrical rhythm is modulated by local influences as well as chemical stimulation. Local influences include, for example, the stretching of muscle tissue by the luminal food content. When food enters the digestive tract or intestine, it distants the muscles and causes basic electrical rhythm. In the same way, there are multiple substances present in the chymes that produce chemical stimulation which results in generation of basic electrical rhythm. Dear students, now we shall discuss the extrinsic mechanisms. First we shall discuss the extrinsic hormonal mechanisms and then we shall discuss the extrinsic neuronal mechanisms. Chym contains many types of chemicals obtained through the food. Some of these chemical substances in chym act as stimulants which cause the release of gastrointestinal peptide hormone, GIP. GIP in turn modulates the motility of the muscle tissue. Dear students, now we shall discuss the extrinsic neural mechanisms. The gastrointestinal tracts, smooth muscles are diffusely innervated by post-ganglionic neurons of sympathetic and para and autonomic nervous system. These are also innervated by aminurgic and peptidurgic neurons. These innervations of neurons control gastrointestinal tracts motility. First we shall discuss the parasympathetic network of neurons which receive their input via the branches of vagus nerve. These neurons are comprised of cholinergic nerves or neurons. Cholinergic neurons produce acetylcholine which is released from their nerve endings. Acetylcholine mediates excitatory actions. For example, increased motility and increased gastrointestinal secretions. The parasympathetic network of neurons is comprised of adrenergic neurons which release norepinephrine from the nerve endings. Norepinephrine's function is inhibitory. It has inhibitory effect on the motility of stomach and intestine so it inhibits the smooth muscle cells to develop action potentials. We shall discuss the innervations of aminurgic neurons which release from their nerve endings. ATP, 5-HT, that is 5-hydroxy-tiptamine. Dopamine and gamma-aminobutyric acid GABA. The peptidurgic neurons which innervate the lining of smooth muscle of the gastrointestinal tracts release many substances as transmitters. For example, N-cafaleins, vasoactive intestinal polypeptide, substance P, gastrine-releasing peptide, neuro-tencine, cholecystokinein and neuro-peptide Y which is also called pancreatic polypeptide. Release of these host of transmitter substances allows a very fine control over the numerous interacting functions of elementary canal. That is because of these too many substances which control this process.