Registered nurses are responsible for carrying out the physician’s instructions. They supervise practical nurses and other auxiliary personnel who perform routine care and treatment of patients. Registered nurses provide nursing care to patients or perform specialized duties in a variety of settings from hospital and clinics to schools and public health departments. A license to practice nursing is required in all states. For licensure as a registered nurse (R.N.), an applicant must have graduated from a school of nursing approved by the state board for nursing and have passed a state board examination.