一、衰老的“自然必然性” 现代国际医学界把人的年龄分成两种:年代年龄和生理年龄。年代年龄,把人的一生分成四个阶段:从初生到20岁为发育期;20～40岁为成熟期;40～60岁为渐衰期;60岁以上为衰老期。生理年龄是指一个人的生理状态而言,有老而不衰的,有未老先衰的。衰老发生在年代年龄组后期,人体对内外环境适应能力逐渐减退,产生一系列生理学和形态学方面的变化,如小脑皮层浦氏细胞减少,脑的重量 First, the aging “natural necessity ” modern international medical community to the human age is divided into two types: age and age of physical. Age, the person’s life is divided into four stages: from birth to 20 years of development; 20 to 40 years of maturity; 40 to 60 years of decline; over 60 years of aging. Physiological age refers to a person’s physiological state, there are old but not bad, there are not old and premature. Aging occurs in the late age group, the body’s ability to adapt to the environment gradually diminish, resulting in a series of physiological and morphological changes, such as the small brain cells of Puer cells, brain weight