The enteric nervous system (ENS) is a subivision of the Peripheral Nervous System, that directly controls the gastrointestinal system. It is capable of autonomous functions such as the coordination of reflexes, although it receives considerable innervation from the autonomic nervous system and thus is often considered a part of it. Its study is the focus of neurogastroenterology. It has as many as one billion neurons, one hundredth of the number of neurons in the brain, and considerably more than the number of neurons in the spinal cord. The enteric nervous system is embedded in the lining of the gastrointestinal system.