What does acetylcholine do?

Acetylcholine has many roles in the body. Upon binding to muscarinic receptors, acetylcholine regulates heart contractions and blood pressure. It also aids in digestion, as it facilitates movement of food in the intestines through the contraction of intestinal muscles. In the lungs, acetylcholine assists to breathe more deeply and inhale more air. It also induces glands to secrete substances such as saliva, tears, and sweat. Acetylcholine also causes pupils to dilate in response to light and regulate vision. 

Upon binding to nicotinic receptors, acetylcholine is involved in skeletal muscle contraction, adrenaline and norepinephrine release from adrenal glands, and activation of the sympathetic system. Both nicotinic and muscarinic receptors play essential roles in memory processes, encompassing long-term and working memory, as well as memory formation and retrieval.