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The blood flow resistance in a vessel is mainly regulated by the vessel radius and viscosity when blood viscosity too varies with the vessel radius. According to very recent results showing the sheath flow surrounding the plug flow in a vessel, [9] the sheath flow size is not neglectible in the real blood flow velocity profile in a vessel. The ...
Blood resistance varies depending on blood viscosity and its plugged flow (or sheath flow since they are complementary across the vessel section) size as well, and on the size of the vessels. Assuming steady, laminar flow in the vessel, the blood vessels behavior is similar to that of a pipe.
Vascular resistance occurs when the vessels away from the heart oppose the flow of blood. Resistance is an accumulation of three different factors: blood viscosity, blood vessel length and vessel radius. [30] Blood viscosity is the thickness of the blood and its resistance to flow as a result of the different components of the blood.
Blood viscosity is a measure of the resistance of blood to flow. It can also be described as the thickness and stickiness of blood. This biophysical property makes it a critical determinant of friction against the vessel walls, the rate of venous return, the work required for the heart to pump blood, and how much oxygen is transported to tissues and organs.
Metabolic vessels – capillaries; Capacitance vessels – veins; Particular feature of resistance vessels is ability to change lumen crossectional area and influence blood pressure. Human arteries or arterioles that are around 0.2 mm or smaller contribute to creation of the blood flow resistance and are called resistance arteries. [2] [3]
Blood, like electric current, flows along the path of least resistance. Resistance is affected by the length and width of a vessel (i.e. a long, narrow vessel has the greatest resistance and a short, wide one the least), but crucially, in the human body, width is generally more limiting than length because of Poiseuille's Law. Thus, if blood is ...
The classic definition by MP Spencer and AB Denison of compliance (C) is the change in arterial blood volume (ΔV) due to a given change in arterial blood pressure (ΔP). They wrote this in the "Handbook of Physiology" in 1963 in work entitled "Pulsatile Flow in the Vascular System". So, C = ΔV/ΔP. [4]
Coronary flow reserve is used in diagnostics and treatment of patients with conditions such as coronary artery disease and syndrome X. [7] In the treatment of these conditions, vasodilators are used to allow sufficient blood to flow past a stenosis, for example, and the measurement of CFR enables the efficacy of such interventions to be measured.