Health is the ability of a biological system to acquire, convert, allocate, distribute, and utilize energy with maximum efficiency. The World Health Organization (WHO) defined human health in a broader sense in its 1948 constitution as "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." This definition has been subject to controversy, in particular as lacking operational value, the ambiguity in developing cohesive health strategies and because of the problem created by use of the word "complete", which makes it practically impossible to achieve. Other definitions have been proposed, among which a recent definition that correlates health and personal satisfaction.
Nursing is a profession within the health care sector focused on the care of individuals, families, and communities so they may attain, maintain, or recover optimal health and quality of life. Nurses may be differentiated from other health care providers by their approach to patient care, training, and scope of practice. Nurses practice in many specialties with differing levels of prescription authority. Many nurses provide care within the ordering scope of physicians, and this traditional role has shaped the public image of nurses as care providers. However, nurse practitioners are permitted by most jurisdictions to practice independently in a variety of settings. In the postwar period, nurse education has undergone a process of diversification towards advanced and specialized credentials, and many of the traditional regulations and provider roles are changing.
In a world where there is so much to be done, I felt strongly impressed that there must be something for me to do.
Dorothea Dix, quoted in Lydia Maria Child, Letters from New York, Vol. 2 (1845), "Letter 31" (31 December 1844), p. 284