世界上所有的动植物都是由元素组成。人体也是由许多元素构成的。据目前所知,地壳表层存在的近百种元素中,几乎全部能在人体内找到。元素依其在人体的含量不同,又可分为宏量元素及微量元素两大类。凡占人体总重量万分之一以上者,如碳、氢、氧、氮、钙、磷、镁、钠、钾、氯、硫都称为宏量元素,共占人体总重量的99.95％。凡占人体总重量万分之一以下者如铁、铜、锌、硒、锰等41种称为微量元素,共占人体总重量的0.05％左右。在这些微量 All animals and plants in the world are made up of elements. The human body is also composed of many elements. As far as we know, almost all of the nearly hundred elements that exist on the surface of the earth’s crust can be found in the human body. Elements according to their content in the human body can be divided into macro elements and trace elements two categories. Where the total body weight more than one ten thousandths, such as carbon, hydrogen, oxygen, nitrogen, calcium, phosphorus, magnesium, sodium, potassium, chlorine, sulfur are called macro elements, accounting for 99.95% of the total body weight. Where the total weight of less than one ten thousandths of the human body such as iron, copper, zinc, selenium, manganese and other 41 kinds of trace elements, accounting for about 0.05% of the total human body weight. In these traces