The structure and physiological functioning of acetylcholine (ACH) was examined and discussed after reading a outline on acetylcholine. Its function as a neurotransmitter at the neuromuscular junction, the effects on muscles when the ACH stimulates the muscle fibers... Drugs which act as agonists and antagonists to ACH and their effect on the systems in small and large doses... The different responses caused by binding to the varied receptors, and how venoms and poisons will affect the system... The addictive qualities of nicotine due to binding to nicotinic receptors and the toxic affects of agonists by binding to muscarine type receptors... The need for the production of esterase enzymes to metabolize the neurotransmitters to halt the responses was examined.