Staz is a pathological condition: its causes and types

The movement of blood through the vessels is a complex physiological process that provides nutrition to all organs and helps to ensure the constancy of the internal environment. Vessels are classified in their sizes into orders: from the first order (the largest) to the second, third, and end with capillaries. The network of the latter permeates all organs and skin, which contains them in large numbers.

Pathological violation of blood supply to the vessels

Environmental and internal factors have an effect on the movement of blood flow, which can be manifested by impaired vascular patency due to aggregation of uniform elements. One such process is stasis. This is a condition in which the patency of the microvasculature is disturbed or slowed down.

With manifestations of stasis, capillaries and venules expand, with the formation of homogeneous columns of red blood cells, but hemolysis and blood clotting are not observed.

Stasis is a reversible process, accompanied by dystrophic changes in the nutrition of tissues and organs. A prolonged and persistent disorder of the supply of useful substances can lead to irreversible phenomena and cause necrosis.

Conditions for the occurrence and course of stasis

The stasis process is the activation of proaggregants, cations and high molecular weight proteins. The aggregates cause bonding, attachment to the walls of blood vessels and the destruction of shaped elements with their complete change. These components include catecholamines, thromboxane A ₂ .

Cations released from blood cells, blood vessels, and tissues are absorbed by the intracellular membrane of the shaped elements, and their excess on it neutralizes their negative charge. The cations of these cells are mainly represented by K ⁺ , Na ⁺ , Ca ⁺ , Mg ²⁺ .

High molecular weight proteins combine with negatively charged membrane ions by amino groups and neutralize them with their positive charge, creating conditions for the attachment of shaped elements to the walls of blood vessels and stick together. Proteins that potentiate shaped elements are gamma globulins and fibrinogen.

Types of Stasis

There are several types of stasis depending on the system where it occurs. But in the blood system , the pathological process is characterized by a violation in the arterial and venous blood supply.

Primary, ischemic and congestive stasis is distinguished.

1. Primary stasis is the activation of proaggregants by blood cells and impaired patency in the lumen of blood vessels by them, which causes hypoxic starvation of a tissue or organ site.
2. Ischemic stasis is a violation of the outflow or arterial blood flow due to the destruction of uniform elements and the occurrence of obstruction of the microvessel.
3. Congestive stasis or venous stasis occurs when the rheological properties of the blood are violated and helps to slow the outflow of blood from microvessels by closing the lumen of the vessels.

External causes of stasis

Among the external causes are the following:

1. Stasis is formed as a result of plethora, which increases the permeability of blood vessels and causes aggregation and gluing of shaped elements.
2. Intoxication with drugs or endotoxins of microorganisms provokes the release of active substances.
3. Exposure to physical factors such as cold, heat, and noise.

Blood coagulation or hemostasis

Hemostasis is a physiological process that ensures the stopping of bleeding in case of violation of the integrity of the vessel at the local level. Its main function is to maintain the constancy of the internal environment of the body. According to the conditions and mechanisms, it is a complex biological system, in which shaped elements, the vascular wall, humoral mechanisms, plasma and tissue mechanisms of the blood coagulation system take part. Violation of the components of hemostasis leads to a violation of blood coagulation.

Consider a small example. Violation of the integrity of the skin leads to a violation of blood vessels and the appearance of bleeding. This leads to the formation of blood stasis in the wound due to the formation of fibrin filaments. In this case, the main components of hemostasis are involved.

The blood coagulation system decreases for several reasons that may be due to acquired or hereditary factors. In the first case, the reasons for the violation of hemostasis are immune reactions under the influence of viruses and drugs, which causes a change in the antigenic structure of platelets. Also, the effects of ionizing radiation, disruption of the bone marrow and chemotherapy of tumor formations cause thrombocytopenia. Increased vascular wall permeability, collagen synthesis disorder lead to increased bleeding.

An example of hereditary disorders is hemophilia, which is transmitted through the male line, and to compensate for it, it is necessary to replenish the missing protective factors in the body with the help of drugs.