The principal sources of regulation of the health care professions are the statutes on the practice of medicine, nursing and midwifery, the rules promulgated pursuant to them and the public health statutes and regulations. These statutes, rules and regulations for the most part define who can do what and under what conditions. They define, either explicitly or by inference, the practice of medicine, nursing and midwifery, and limit the right to engage in practice to licenced or registered individuals.