Arteriole

An arteriole is a muscular type artery, which is the thinnest artery in the human body. Its diameter is less than 300 microns, which approximately corresponds to the diameter of a human hair. Arterioles arise from large arteries and become tiny capillaries, where the exchange of substances between blood and tissues occurs.

One of the main functions of arterioles is to regulate blood flow and blood pressure in the human body. Arterioles are able to narrow and expand under the influence of the autonomic nervous system, which ensures the regulation of blood flow and maintenance of optimal blood pressure in various organs and tissues.

The narrowing of arterioles is called vasoconstriction, and the widening is called vasodilation. Vasoconstriction of arterioles leads to a decrease in blood flow in the corresponding area, while vasodilation, on the contrary, increases blood flow. Thus, arterioles play an important role in maintaining homeostasis in the body by ensuring sufficient blood flow to tissues and organs under various physiological conditions.

The best known arterioles are the renal arterioles, which are involved in regulating blood flow and filtering blood in the kidneys. Arterioles also play an important role in regulating blood flow to muscles during exercise and during periods of stress.

In conclusion, arterioles are important elements of the circulatory system, providing the necessary blood flow to tissues and organs. Their ability to contract and expand under the influence of the autonomic nervous system makes them key regulators of blood flow and blood pressure in the human body.

Arterioles are the thinnest muscular arteries that play an important role in regulating blood flow in the human body. They have a diameter of less than 300 micrometers and many tiny capillaries extend from them, which ensure the exchange of substances between blood and tissues.

Arterioles are found in various organs and tissues such as the heart, brain, lungs, kidneys, liver, etc. They regulate blood pressure and blood flow by narrowing or expanding their lumen under the influence of the autonomic nervous system. This allows the body to adapt to different conditions and needs.

However, if the arterioles are damaged or blocked, it can lead to various diseases such as stroke, heart attack, kidney failure and others. Therefore, it is important to monitor the condition of the arterioles and take measures to protect them.

Overall, arterioles play an important role in maintaining the health and functioning of the human body.

Arterioles (Latin arteriola - “small artery” from arter- “artery” + -o- “small”) are the thinnest arteries, the majority of which in humans are muscular arteries with modest sizes less than 0.3 mm in diameter.

Arterioles in the human body account for only 1.5-5% of all arteries penetrating the circulatory system. The arteries are considered to be the main masters of the circulatory system. Arteries, in turn, are the largest vessels in the circulatory system. Arterial tubes are capable of stretching through the entire thickness of the body, and their capacity (that is, the volume of blood flow) is significantly higher than microscopic arterioles. This is due to both the diameter of the vessels themselves and the power of blood flow. The arteries in some places have a lumen of up to 20 mm, reaching the aorta of the main trunk - the largest artery in the body.

The main feature of arterioles, unlike arteries and veins, is their ability to regulate their own lumen due to the ability to work in the mode of expansion and contraction. This process is regulated by the autonomic system at the expense of the sympathetic one, while the medulla oblongata controls parasympathetic activity. The operation of these processes occurs as follows: the central nervous system of the body, including the brain, based on the data obtained in the process of perception of analyzers, triggers the release of hormones into the blood, which react with the reacting structures in the vessel wall - the endothelium. When the concentration of hormones exceeds the norm, this leads to a narrowing of the smallest vessels, which, passing through the walls, are filled with blood. This narrowing avoids various hydrostatic changes that can cause blood flow to become uneven. At the same time, the blood flow becomes denser and saturated with oxygen. In addition, this “consistency” of blood can be considered the cause of increased blood pressure. But when the concentration of biologically active substances decreases, the vessels begin to dilate, which is also regulated by receptors on the inner lining, which, upon contact with acetylcholine, begins to produce electrical excitatory potentials. This is how the body regulates its own levels of arterial and venous pressure. In addition, the receptors on the wall also affect the functional state of the smallest blood vessels.