Health care is the maintenance or improvement of health via the prevention, diagnosis, and treatment of disease, and other physical and mental disability in people. Health care is delivered by health professionals in health care systems. Physicians and physician associates are a part of these health care professionals. Dentistry, midwifery, nursing, medicine, pharmacy, psychology, physical therapy and other health professions are all part of health care. It includes work done in providing primary, secondary, and tertiary care in public health.