HLSC 1F90 Lecture Notes - Lecture 16: Population Ageing, Brain Death, Osteoporosis
Document Summary
Life expectancy: average length of time an individual person is expected to live (increasing since 1950) Life span: projected length of life based on the maximum potential of the human body in the best environment. Health span: period of life occupied by health and freedom from chronic or serious disease. Japans speed of population aging has increased by 26% Canadas speed of population aging has increase by 15% Generation: average period between the birth of parents and the birth of their offspring (typically 20-30 years) Aging is caused by external forces acting on the body cells and there are ways to slow down the process. Free radical theory: cells are damaged by free radicals which leads to aging. Somatic mutation theory: chromosomes are damaged by exposure to toxins and/or radiation. Wear and tear theory: damage from everyday wear eventually exceeds the body"s ability to repair itself. Aging is internally regulated by a biological time clock and nothing can change it.