Interesting facts about the human circulatory system

The speed of movement of blood in the vessels of the human body reaches 15-20 centimeters per second in the aorta and slows down to 0.5 millimeters per second in the capillaries.

The complete circulation of blood, during which a particle of it, leaving the aorta, again returns to the capillaries of the body, is equal to 20-24 seconds. With hard physical work, the blood circulation increases by 4-5 times.

Through the lumen of the capillary - the smallest vessel, equal (by the smallest diameter) 0, 008 millimeters, only one blood cell - an erythrocyte - can pass. The capillary is 50 times thinner than a human hair. The entire human body is dotted with these vessels, and if they are stretched in one line, then the total length of an adult will be 100 thousand kilometers? This is with the length of each capillary 0.5 mm.

The diameter of an erythrocyte is only 0.007 millimeters. In one cubic millimeter of blood, there are 4.5-5 million erythrocytes, and in 5 liters of blood contained in the human body - about 25 trillion.