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人的心脏是从胚胎的第三周开始跳动,经过婴儿、少年、青年、老年,一直到死。如果以每分钟跳动70次计算,一昼夜跳动的次数就超过10万次。人活到60岁,他的心脏就要跳22亿次。刚落生的婴儿的心脏象球形,到了12岁时,男孩的心脏外形象只小鸭梨,女孩的心脏象个鸭蛋。进入成年以后,男女的心脏都象个大鸭梨。婴儿的心脏只有16—17克,一岁就增加了二倍,五岁时增加了三倍,16岁时增加了16倍。成年人的心脏重量是250—260克,相当于人体重的1/200,大小如拳头,80%是水份。心脏工作效率很高,每分钟经过心脏搏出的血液有8—10斤,一昼夜搏出血液达1.斗万多斤,一年能输出血液400多万斤。如果一个人活到70岁,他的一生从心脏输出的血液达2.8亿
The human heart is beating from the third week of the embryo, through infants, adolescents, youth, old age, until death. If the beating 70 beats per minute calculation, the number of beats a day and night more than 100,000 times. People live to 60 years old, his heart will jump 2.2 billion times. The heart of a newborn baby is spherical in shape. By the age of 12, the heart of a boy looks like a duck and pear, and the heart of a girl resembles a duck egg. Into adulthood, the heart of men and women are like a big pear. The baby’s heart is only 16-17 grams, doubling at one year of age, tripling at five and 16 times at age sixteen. The heart weight of an adult is 250-260 grams, which is equivalent to 1/200 the body weight, the size of a fist, 80% is water. Cardiac work efficiency is high, every minute through the heart beating the blood 8-10 pounds, a day and night stroke out of blood up to 1 million kilograms, a year can output more than 400 kg of blood. If a person lives to be 70 years old, his life blood output from the heart of 280 million