A nurse is a healthcare professional who, in collaboration with other members of a health care team, is responsible for: treatment, safety, and recovery of acutely or chronically ill individuals; health promotion and maintenance within families, communities and populations; and, treatment of life-threatening emergencies in a wide range of health care settings. Nurses perform a wide range of clinical and non-clinical functions necessary to the delivery of health care, and may also be involved in medical and nursing research. Nurses have been working in the professional field since ancient times. Typically, nurses are distinguished from one another by the area they work in (critical care, preoperative, oncology, nephrology, pediatrics, adult acute care, geriatrics, psychiatric, community, occupational health, etc.).