What distinguishes the arteries from the veins: the features of the structure and functioning
The circulatory system of man, except the heart,consists of different in size, diameter, structure and functions of the vessels. What is the difference between arteries, veins and capillaries? What features of the structure make it possible to carry out the most important functions? These and other questions will be answered in our article.
The circulatory system
The performance of blood functions is possible due to itsmovement through the system of blood vessels. It is provided by rhythmic contractions of the heart, working like a pump. Moving along blood vessels, blood transports nutrients, oxygen and carbon dioxide, protects the body from pathogenic microorganisms, provides homeostasis of the internal environment.
Vessels include arteries, capillaries and veins. They determine the way of blood in the body. What is the difference between arteries and veins? The location in the body, the structure and the functions performed. Let us consider them in more detail.
Than arteries differ from veins: features of functioning
Arteries are the vessels that providethe flow of blood from the heart to tissues and organs. The largest artery in the body is called the term "aorta". It comes directly from the heart. In the arteries, blood moves under high pressure. To maintain it, you need a suitable structure of the walls. They consist of three layers. The inner and outer are formed by a connective tissue, and the middle one is made from muscle fibers. Thanks to this structure, these vessels are capable of stretching, which means they can withstand a great pressure of blood flow.
How does the structure of the veins differ from the structure of the arteries? First of all, vessels of another type carry blood from the organs and tissues to the heart. Passing through all the cells and organs, it is saturated with carbon dioxide, which carries to the lungs.
Another important issue is what distinguishesthe structure of the wall of the artery and vein. The latter have a more delicate muscular layer, so they are less elastic. Since the blood in the veins comes under low pressure, their ability to stretch is not so important.
The value of blood pressure in vessels of different typesshow different types of bleeding. With arterial blood, the blood is pulsed with a pulsating fountain. It is scarlet, because it is saturated with oxygen. But with venous - it flows with a slow jet and has a dark color. It is determined by the large amount of carbon dioxide.
The lumen of most veins has specialized pocket valves that prevent the blood from flowing in the opposite direction.
How arteries differ from veins, we sorted out. And now let's pay attention to the smallest blood vessels - capillaries. They are formed by a special kind of integumentary tissue - endothelium. It is through him that there is a metabolism between the tissue fluid and blood. Due to this, a continuous gas exchange takes place.
Arteries, coming out of the heart, break up intoCapillaries that fit every cell of the body, merging into venules. The latter, in turn, combine into larger vessels. They are called the veins that enter the heart. In this continuous journey of blood, the capillaries perform the crucial role of direct contact between the elements of the blood and the cells of the whole organism.
Movement of blood in blood vessels
What distinguishes arteries from veins, clearlydemonstrates and the mechanism of blood flow. During the contraction of the heart muscle, blood is pushed out with force into the arteries. In the largest of them - the aorta, the pressure can reach 150 mm Hg. Art. In capillaries, it drops significantly to 20. In the hollow veins, the pressure is minimal and is 3-8 mm Hg. Art.
What is the tone and blood pressure?
In the normal state of the body, all the vesselsare in a state of minimum tension - tone. If the tone increases, the blood vessels begin to narrow. This leads to increased pressure. When this condition becomes sufficiently stable, a disease arises called hypertension. The reverse long-term process of lowering the pressure - hypotension. Both of these diseases are very dangerous. In the first case, such a state of blood vessels can lead to a violation of their integrity, and in the second - to a deterioration of blood supply to organs.
Summing up: how do arteries differ from veins? These are the features of the structure of the walls, the presence of valves, location in relation to the heart and the functions performed.