Gerontology is the scientific and multidisciplinary study of ageing and the problems, needs and experiences of older persons. It examines ageing from biological, psychological, social, economic and cultural perspectives. Unlike geriatrics, which mainly deals with the medical treatment of diseases in older people, gerontology has a broader focus on the overall process of ageing and the quality of life of elderly persons. Ageing is a natural and continuous process that brings physical, psychological and social changes. Biological ageing may involve reduced strength, sensory abilities and resistance to illness. Psychological ageing may influence memory, emotions, adjustment and coping abilities. Social ageing is associated with changes in