Acetylcholine acts mainly as a diastolic agent in smooth muscle, which is mainly distributed in the muscular layer of blood vessels and in the tissues of the gastrointestinal tract, as well as in the local urinary system. Since acetylcholine has a wide range of action and is not targeted to a particular place, the cholinergic neurotransmitter is less selective, and it is mainly used in the smooth muscle of the blood vessels to diastole arteries and veins. In the gastrointestinal tract, it can increase the motility of the smooth muscles of the gastrointestinal tract and the diastole of the gastrointestinal sphincter, resulting in enhanced gastrointestinal secretion. There is also the bladder forcing muscle, which can be contracted when acting on the bladder forcing muscle and can be diastolic when acting on the deltoid sphincter. There is also the iris pupillary sphincter, which can be made to shrink and can cause the ciliary muscle to contract, and acetylcholine has no use.