The total length of an adult's blood vessels is about 100,000 kilometers and can circle the earth more than twice (the circumference of the earth is 40,075.).02 km). The vascular system is composed of arteries, veins and capillaries, the arteries originate from the heart, continue to branch, the caliber gradually thins, the wall gradually thins, and finally divides into a large number of capillaries, which are distributed between tissues and cells throughout the body; The capillaries then gradually merge into veins and eventually return to the heart. Arteries and veins are the tubes that carry blood, while capillaries are where blood and tissues exchange substances. The blood in each person's body is proportional to their own body weight, and the blood of the general body accounts for 7%-8% of their own body weight, which is why China's blood donation law stipulates that the weight of adult male blood donors should not be less than 50kg, and the weight of adult female blood donors should not be less than 45kg.
There are a total of 206 bones in a normal human body. Among them, there are 7 bones in the cervical spine, 12 bones in the thoracic spine, 5 bones in the lumbar spine, and a total of 24 ribs in the human body. Different parts of the bone have different functions. For example, the 24 ribs make up the rib cage, which can protect the lungs.
There are about 639 muscles in the whole body. It is composed of about 6 billion muscle fibers, of which the longest muscle fiber is 60 centimeters, and the shortest is only about 1 millimeter; Large muscles weigh 2,000 grams, while small muscles weigh only a few grams; The average person's muscles account for 35-45% of their body weight; The total length of capillaries in the muscles can reach 100,000 kilometers, which can circle the earth two and a half times.
According to statistics, a normal adult can fart 10 to 15 times a day, and the total volume can reach 500ml.