In mathematics teaching, teachers can use some figures in the human body as examples, on the one hand, let students know this knowledge, on the other hand, these examples can increase students' interest. Here are some figures about the human body (normal adults):

The human body is composed of 100 trillion cells, and the whole body is covered with skin, with a total area of about 2 square meters.

The heart weighs about 260 grams and has a volume of 750 ml. During contraction, 70 ml of blood is injected into the blood vessel each time, the output per minute is 5000 ml, and 7500 kg of blood is injected within 24 hours. The heart beats 60~ 100 times per minute. A person's life beats about 300 million times.

The lung weight is about1000 ~1300g, and the ventilation of normal people is 4200~6600 ml per minute.

There are about 10~ 15 tons of food in a person's life, and 50~80 tons of water is processed by the stomach and intestines.

The liver weighs about1300g and is the largest digestive gland in human body. Hepatocytes secrete about 100 ml bile every day, and can silently carry out more than 500 chemical reactions. Therefore, the liver is called the largest chemical plant in the human body.

The kidney is an important device for water level balance in the human kingdom, weighing about 300 grams, and consisting of more than 4 million basic components-nephron. The length of the inner renal tubule is about 50~60 mm, and the total area of microvilli near the glomerular tubule is 50~60 square meters. About 65,438+0,200 ml of blood passes through the kidney every minute, which can filter the whole body blood in about 27 minutes, catch nutrients that should not "leave the country" and discharge waste. Normal people's kidneys produce about 120~ 140 ml of urine every minute, and the amount of urine produced every 24 hours is180l, of which 99% is absorbed, and 1% is the final urine, with the amount of about 1.5 litres. Urine reaches the bladder through a 25 cm long sewer-ureter. If it accumulates to 400~500 ml, there will be urine. With the consent of the head office-brain, the reservoir will automatically release the brake, and the volume of the bladder is generally 1000 ml, which is excreted through the water pipe-urethra.

In the endocrine family, the thyroid gland weighing about 25 grams is called "iodine bank", containing 500 micrograms of iodine, accounting for 90% of the whole body content; Adrenal weight10g; The ovary weighs about 6 grams; The pituitary gland is only 0.6 grams; The smallest parathyroid gland is only 0.1.3g; The pancreas with dual functions weighs 660 ~100g, and contains100 ~ 2 million islets, with a total number of cells of about 500 ~1000,000. Its joys and sorrows will have a great impact on human blood sugar. These substances secreted by endocrine glands are called hormones, which unfairly regulate the growth, development and metabolism of the body and are also the root cause of the differences between men and women.

206 bones and more than 600 muscles are the scaffolds of human body, which have important protection, support and movement functions for internal organs. The whole body skeleton weighs about 9 kg, accounting for 1/5 to 1/7 of the body weight.

The eye is like a strange camera, which can distinguish more than 150 colors in the spectrum. It contains120,000 rod cells and 6.5 million cone cells. The eardrum of the ear has a surface area of 50~90 square millimeters; The nose can smell more than 2000 different smells, and the olfactory receptor-olfactory epithelium has a surface area of 500 square millimeters.

The diameter of a hair is 105! 200 microns, its life span is about 4 years, healthy people have to shed 40~50 hairs every day, and of course there is new growth, each hair is about 0.4 mm long every day. Beard, the second characteristic unique to men, totals 2000~3000.

The highest headquarters of the human kingdom consists of six brothers, namely the brain, the cerebellum, the midbrain, the diencephalon, the pons and the medulla oblongata, collectively referred to as the brain. * * * Weight1300 ~1500g, volume 1600 cubic centimeter, containing14 billion neurons, with 90,000 neurons.

The total blood of a normal person accounts for 8% of his body weight, that is, a person weighing 50 kg has about 4 kg (equivalent to 4000 ml) of blood.

A 10-month-old baby has about 300~500 ml of blood.

The heart only accounts for 0.5% of the body weight, but it has great functions. It can eject blood at a speed of 8 meters per second, making blood flow 500 meters per minute, about 30 kilometers per hour, 700 kilometers a day and night, and 250,000 kilometers a year. In 60 years, the distance that blood flows through is 65.438+0.5 billion kilometers, which is equal to 375 times around the equator of the earth.

When a sperm is combined with an egg, due to the possible combination of chromosomes, the probability of a couple having different types of children can reach more than 7 billion.

When a wrinkle grows on your forehead, you should frown at least 200,000 times.

Each nipple on the tongue contains 250 taste buds, and each taste bud can only taste one taste. Sweet, sour, salty and bitter are distinguished by different taste buds.

The weight of human skin is equivalent to 20% of human body weight. The average total area of adult skin is 17 square meters, and each square centimeter of skin is composed of 2 million cells on average.

When the eye is dark for one minute, its sensitivity to light increases to 10 times; 20 minutes to 6000 times, 40 minutes to 25000 times. People's eyes can see candlelight 20 kilometers away in the dark night. The human eye can distinguish more than 8 million shades.

There are 100 sweat glands, 12 sebaceous glands, 4-meter-long nerve fibers, 150 nerve endings and nearly one meter-long blood vessels in a square centimeter of skin.

Every second, about 654.38+ million different chemical reactions occur in human brain, forming thoughts, feelings and actions.