One of the wonders of the human body is the cardiovascular or circulatory system, which consists of the heart, blood and different blood vessels, that is, arteries, veins and capillaries. There are those who do not know the differences between these conduits and what the function of each of them is, so we enter this gigantic highway through which red gold flows.
To begin with, a fact that shows the complexity of this system. If the entire conglomerate of arteries, veins and capillaries of a single person could be placed in a straight line, a length of 100,000 kilometers would be obtained, that is, two and a half times the revolution around the Earth.
An average of five liters of blood circulate through the veins and arteries (between 4.5 and 6, depending on sex, age, weight and height), which is responsible for carrying oxygen, cells and nutrients necessary to carry out the entire body. vital functions.
Let’s now see how the device works. The heart receives blood with oxygen and nutrients, called arterial blood, from the lungs, and then pumps it to water and feed each cell in the body. Once the journey is completed, the blood returns to the right side of the heart full of carbon dioxide and other waste substances and, from there, it is sent to the lungs, where it will be oxygenated again.
And this is what each blood vessel does, according to the EL MUNDO Salud special on the heart:
They conduct blood in a centrifugal direction; That is, they are responsible for distributing this liquid rich in oxygen and nutrients from the heart to the entire body (except the pulmonary artery, which carries blood with waste substances to the lung so that it becomes oxygenated again).
Large arteries, such as the aorta, are responsible for distributing blood to smaller arteries or arterioles. The latter, which can contract or relax to control blood flow, carry blood to the capillaries.
They are the tubes that are responsible for transporting blood to the heart. The venae cavae (superior and inferior) carry waste-filled blood to the heart, while the pulmonary vein returns oxygen-rich blood from the lungs to the heart.
Small vessels that connect arterioles with veins. Inside, an exchange occurs between respiratory gases, nutrients and waste substances. This process occurs in two modalities:
In short, the arteries are responsible for distributing oxygenated blood from the heart, while the veins transport poorly oxygenated blood back from the capillaries to the heart to be re-oxygenated by the lung. Arteries leave the heart and veins return to it.
Another difference is the thickness, since veins have thinner walls than arteries. This is because veins have a lower pressure level than arteries and do not need to be as thick.
We must not forget that this entire process develops ceaselessly throughout life. The heart beats 70 times per minute, 100,000 times per day and 40 million times per year. In a single minute it is capable of pumping five liters of blood (which is equivalent to 7,500 liters per day) throughout the entire network of veins, arteries and capillaries; That is the blood flow per minute at rest, since during periods of effort, it can reach 35 liters.