Body processes

Plasma Viscosity – Function, Task & Diseases

Plasma viscosity

Plasma viscosity and blood viscosity are not the same, but they are closely related. The plasma makes the blood flowable because it consists mainly of water. When the cellular plasma components increase, the blood can lose its physiological viscosity.

What is plasma viscosity?

Viscosity is a measure that describes the viscosity of fluids. The higher the viscosity, the thicker or more viscous the fluid is. Viscous fluids combine liquid properties with material properties. When the viscosity is high, the individual molecules of a fluid are bonded all the more strongly. This makes them less mobile and the liquid has less fluidity.

Viscous liquids do not behave as Newtonian fluids, i.e. they do not behave proportionally. Viscosity is present in different milieus of the human body, such as the blood. Accordingly, human blood does not behave like a Newtonian fluid, but shows an adaptable and erratic flow behavior that is determined by the Fåhraeus-Lindqvist effect .

In vessels with a narrow lumen, for example, the viscous blood has a different consistency than in vessels with a wide lumen. These relationships keep the erythrocytes from clumping.

The viscosity of blood plasma is called plasma viscosity. It depends on the concentration of the individual plasma proteins and is thus determined, for example, in particular by the plasma level of fibrinogen. In addition, plasma viscosity changes with temperature. Since the plasma is more liquid, it improves the flow properties of the blood.

The so-called hemodynamics deals with the plasma viscosity, the blood viscosity and the relevant factors.

function & task

The plasma has a special flow mechanics that is determined by different forces. Parameters such as blood pressure , blood volume , cardiac output , plasma or blood viscosity and the vascular elasticity of the blood vessels are just as important factors in this context as the lumen of the blood vessels .

All of the factors mentioned influence each other. A change in the blood volume, the lumen, the vascular elasticity, the blood pressure or the cardiac output therefore has a retroactive effect on the viscosity of the blood. The same applies in the opposite direction. In addition, the blood viscosity depends on the [[hematocrit||, on the temperature, on the erythrocytes and their deformability. The viscosity of the blood is determined by many physical and chemical properties.

The blood viscosity ultimately contributes to the ideal control of the body’s blood flow to cover individual organs and tissues as required.

Unlike other fluids in the human body, blood does not behave as a Newtonian fluid in terms of its flow behavior, i.e. it does not flow linearly. Instead, its erratic flow behavior is mainly determined by the Fåhraeus-Lindqvist effect. The effect changes the viscosity of the blood depending on the diameter of the vessel. Blood is less viscous in vessels with a smaller diameter. This prevents capillary stasis. Thus, blood viscosity is characterized by differences at different points in the bloodstream .

The basis for the Fåhraeus-Lindquist effect is the deformability of red blood cells . Shear forces occur in the vicinity of vessel walls, which displace the erythrocytes into the axial flow. This axial migration of the red blood cells creates a cell-poor peripheral flow . The plasma edge current serves as a kind of sliding layer that makes the blood appear more fluid.

Plasma is about 93 percent water and contains about seven percent proteins , electrolytes , nutrients , and metabolic metabolites. Ultimately, plasma liquefies the blood, reduces its viscosity and creates better flow properties for the red blood cells. Since plasma viscosity acts on blood viscosity, any changes in plasma viscosity affect the flow properties of blood itself.

Diseases & Ailments

The blood viscosity is determined in viscometry. The measuring method determines the flow velocity based on the temperature- and pressure-dependent flowability and the resistance as well as the internal friction. The viscosity of plasma can in turn be measured using a capillary viscometer. In contrast to determining blood viscosity, the effect of shearing forces does not have to be included in the calculation.

There is a close connection between plasma viscosity, blood viscosity, flow dynamics and blood flow in body tissues. Thus, abnormal plasma viscosity can have serious consequences for the supply of nutrients and oxygen to all body tissues.

A pathological change in plasma viscosity is in most cases associated with serious diseases. As part of this, the so-called hyperviscosity syndrome can occur. Changes in plasma viscosity mostly depend on changes in the concentration of plasma proteins. An increase in plasma proteins also occurs in the context of hyperviscosity syndrome. In this clinical complex of symptoms, primarily the concentration of paraproteins in the plasma increases, as a result of which blood viscosity increases and fluidity decreases.

Hyperviscosity syndrome can occur in the context of Waldenstrom’s disease. With this complex of symptoms, the IgM concentration in the blood increases. The IgM molecule is a large molecule composed of Y-shaped units and gives rise to hyperviscosity syndrome at plasma concentrations of 40 g/l.

Hyperviscosity syndromes due to increased paraprotein levels also characterize malignant diseases. In addition to multiple myeloma , a benign disease can also provide the framework for the increase in viscosity in individual cases. This applies in particular to Felty’s syndrome , lupus erythematosus and rheumatoid arthritis .

Other types of so-called immune complex diseases also lead to the deposition of immune complexes that impair plasma viscosity and blood flow properties. Since the flow properties of blood can also change as a result of immobilization, pathological agglomerations of red blood cells often occur in immobile patients.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.