A blood vessel is a tubular structure for transporting blood. The vessel is also referred to as a vein and occurs only in the human and animal body.

What are blood vessels?

The whole of the blood vessels forms the blood circulation together with the heart. This is essential for the circulation of the blood to supply body parts. The blood vessels themselves are divided into different categories depending on their severity and function. The most important is the aorta as the main artery. Add to that the arteries. Your job is to lead blood away from the heart. In contrast, veins bring blood to the heart.

The capillaries play an important role last. As so-called capillaries they form the branching of the arteries. A blood vessel is made of tissue enveloped by at least one wall layer. Thus, the vein acts as a hollow organ and is responsible for the lossless blood transport. The transport network with all its branches reaches a length of up to 150, 000 kilometers. 75 percent of the blood is in the veins, another 20 percent in the arteries and only 5 percent in the capillaries.

Anatomy & Construction

A blood vessel can be divided into three layers: the intima, the media and the adventitia. The former layer is the innermost layer of the vessel wall. In science it is called Tunica interna . Characteristic of the intima is that it consists of only one layer of vascular cells. The cells are arranged so that the best possible exchange of gases and liquids between the blood and the vein is possible. Specifically, the intima consists of a basal membrane. This is a layer of connective tissue cells that have long been aligned with a vessel.

In contrast, the media is a muscle layer, which is covered on both sides by connective tissue. In addition there is the adventitia consisting of a loose connective tissue. It has the goal of embedding the blood vessel within the body. It should be noted that capillaries are only covered by a single layer. It is composed of vascular cells and resembles the intima in their shape and expression.

Function & Tasks

In the human body, blood vessels branch into almost all body parts. In addition to the transport of blood, their task is always to provide the body with nutrients. Here, the vessel diameter of the veins plays an important role. Depending on the width of the blood circulation varies and the associated nutrient supply. To control the vessel diameter, blood vessels can change in size.

This succeeds with the contraction of the muscle layer. The intensity of the contraction is in turn regulated by the body's autonomic nervous system. With vasodilatation and vasoconstriction, the nervous system also succeeds in regulating oxygenation. Enclosed is the core temperature controlled within the internal organs. Depending on the species, veins take on a specific task. For example, the aorta fulfills the so-called wind boiler function. This is a mechanism responsible for balancing the pressure of the blood expelled from the heart.

So-called baroreceptors measure the pressure of the blood, so that the aorta can react in case of a change with a vasodilatation or a vasoconstriction. Another important task is fulfilled by the vena cava. These are two relatively large veins that carry venous blood to the right atrium. Venoles fulfill a special role. They are a scaled-down version of the veins that enable a deep branch of the transport network.

Diseases & complaints

The circulatory system is a vulnerable system. In many cases, a malfunction of the blood vessels is the cause of a complaint. The most common disease is atherosclerosis. Colloquially, it is referred to as arteriosclerosis. The disease causes thickening and hardening of the veins. As a result, the vessels narrow, which hinders the circulation of the respective body region. Cause of arteriosclerosis is a genetic predisposition. However, risk factors such as smoking or weight gain may favor the onset of the disease.

In addition, hemorrhoids are also a common disease of the bloodstream. This is called a knot-shaped dilation of the arteries within the rectum. The dilation of the blood vessels can be attributed to an increasing connective tissue weakness. Patients experience pain and persistent itching at the affected area. Left untreated, inflammation and eczema associated with the secretion of mucous secretions may occur.

Hemorrhoids can be alleviated by the use of ointments and suppositories. In the long term, however, it is important to change the way people live. Otherwise, it may come to another outbreak. On the other hand, a thrombosis, also known as blood clots, leads to a particularly severe disorder of the blood circulation. Here, a closure of a single blood vessel takes place. This results in the obstruction of the bloodstream and is associated with a reduced oxygen supply. In severe cases, thrombosis can cause a pulmonary embolism and be fatal.

Another disease of the blood vessels is finally the varicosis, colloquially known as varicose veins. This causes a thickening of veins in the legs. The cause may be a connective tissue weakness. Noticeably, the varicose makes itself through a sense of tension and heaviness. There is also an itchy skin, which increases in intensity as the disease progresses.

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