The heart and brain are the two most important organs in our body. Do you know their size? Studies show that the human heart is about the size of a person's right fist, while the human brain is about the size of two fists combined. It seems that we can know the size of the heart and brain by measuring the volume of a person's fist.
Steps:
The first, second and third average values of the measurement results.
Calculation: the volume of my heart: the volume of my brain:
If people's cerebral cortex is unfolded and wrinkles are smoothed, you can get a "cake" with a thickness of 3 mm and an area of 90++60 square centimeters.
The average weight of adult male brain is 1.424 g, and it shrinks to 1.395 g in old age. The weight record of male brain is 2049 grams. A normal brain without atrophy weighs 65,438+0,096 grams. In contrast, the brain of a nine-meter-long dinosaur was only the size of a walnut and weighed 70 grams.
The signal transmission speed of human nervous system reaches 288 kilometers per hour, which slows down in old age 15%.
The average length of human tongue is 9 cm and the weight is 50 g, and the tongue is composed of 17 muscles, so it is extremely flexible.
The older you get, the longer your ears get. The average ear length is 2.2 mm every ten years.
People have 1 10,000 ~ 3 million hairs. If possible, men go to the barber shop regularly, and their shaved hair is 9 meters ~ 10 meters long.
If a person can live to be 75 to 80 in his life, his heart will beat 3 billion times. A heart weighing about 300 grams will send blood to the whole body through a vascular system with a total length of about 200,000 kilometers.
A human body weighing about 70 kg contains chemical components: carbon 12 kg, hydrogen 7 kg, calcium 1 kg, and a small amount of iodine, cobalt, manganese, aluminum, chromium and silver.
Women can eat 25 tons of food and drink 37,000 liters of liquid in their lifetime. A man can eat 22 tons of food and drink 33,000 liters of liquid in his life. Women eat more than men in their lifetime, because their average life expectancy is longer than that of men. Women cry five times as often as men, and as a result, their average life expectancy is seven years longer than that of men.
muscle strength
A person has more than 600 muscles. They are big and small, long and short, flexible and tacit, providing power for every movement of people. So some people call muscles the engine of the human body.
At first glance, muscles are soft and weak, but the strength of generate when contracting is quite amazing. According to calculation, if the muscles of 6 square centimeters contract at the same time, they can lift 20 ~ 60 kilograms. If 300 million muscle fibers in the whole body contract in one direction, it will produce a force of 250,000 Newton (1 Newton is equivalent to 0. 1 kg force), which is worthwhile.
[Edit this paragraph] The Almighty Hand
The hand is a universal tool for human beings. Eating, dressing, writing, playing the piano, playing ball, farming, working and operating the computer, what can we do without hands? It is estimated that human hands can make hundreds of millions of movements.
Our hands have a fine structure. One hand has 8 carpals, 5 metacarpals, 14 phalanges, 59 muscles and a well-developed neurovascular system.
Our hands are very dexterous. In one second, a person's palm can be turned many times. In one second, a pianist can tap the keys dozens of times with his fingers, as fast as a meteor. Surgeons used these dexterous hands to sew up blood vessels and nerves with diameters less than 1mm, and dental sculptors carved thousands of words on an ivory grain as big as rice grains.
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