Aging

The physical and mental changes that occur with the passing of time. Aging is associated with degenerative changes in various organs and tissues, such as loss of elasticity in the skin and a progressive decline in organ function. Mechanical wear and tear causes cumulative damage to the joints, and the muscles lose bulk and strength. Wound healing and resistance to infection also decline. Gradual loss of nerve cells can lead to reduced sensory acuity and difficulties with learning and memory. However, dementia occurs in only a minority of elderly people. Heredity is an important determinant of life expectancy, but physical degeneration may be accelerated by factors such as smoking, excessive alcohol intake, poor diet, and insufficient exercise.