In medicine, the heart is a solitary organ, but the cardiovascular system is a circular structure consisting of the heart, each layer of arteries, a large network of capillaries, and a layer of veins.
This seems to be a small problem. In fact, it is a big problem related to the core architecture of cardiovascular medicine. Because of all cardiovascular functions, the prevention, diagnosis, treatment, and rehabilitation of cardiovascular diseases are all derived from this network cycle structure, not the heart itself.
If you know that the cardiovascular system is a network, what kind of network is the cardiovascular system?
Let's take a walk in this network. Our blood will be emitted from the left ventricle, through the aorta, aorta, middle artery, arteriole, and finally to the capillaries that allow only the smallest cells of the body to pass through. It is only as thin as one tenth of a strand of hair. Capillaries bring oxygen and nutrients to the body of 37.2 trillion cells, then recover from capillaries to the venules, middle veins, central veins, and finally back to the right atrium, to the right ventricle, with As the heart contracts, the blood emanating from the right ventricle passes through the layers of arteries, capillaries, and veins of the lungs, bringing oxygen back to the left atrium and to the left ventricle.
The trip is over, how far have we gone? If the whole body's blood vessels, from the arteries to the veins, add up to 176,000 kilometers, around the Earth's equator, about four and a half. It is in this underlying structure that the cardiovascular system completes all its functions, delivering oxygen and nutrients to the body, and taking away the metabolic waste of each tissue. At the same time, in response to our needs, we can adjust the distribution of blood in each organ at any time to adapt to all the scenes of our social function.