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When vasodilation causes systolic blood pressure to fall below 90 mmHg, circulatory shock is observed. [11] Vascular resistance depends on several factors, including the length of the vessel, the viscosity of blood (determined by hematocrit) and the diameter of the blood vessel. [18]
Hyperviscosity syndrome is a group of symptoms triggered by an increase in the viscosity of the blood.Symptoms of high blood viscosity include spontaneous bleeding from mucous membranes, visual disturbances due to retinopathy, and neurologic symptoms ranging from headache and vertigo to seizures and coma.
A diagram explaining factors affecting arterial pressure. Pathophysiology is a study which explains the function of the body as it relates to diseases and conditions. The pathophysiology of hypertension is an area which attempts to explain mechanistically the causes of hypertension, which is a chronic disease characterized by elevation of blood pressure.
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.
In the arterioles blood pressure is lower than in the major arteries. This is due to bifurcations, which cause a drop in pressure. The more bifurcations, the higher the total cross-sectional area, therefore the pressure across the surface drops. This is why [citation needed] the arterioles have the highest pressure-drop. The pressure drop of ...
Bradykinin (BK) (from Greek brady-'slow' + -kinin, kīn(eîn) 'to move') is a peptide that promotes inflammation.It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and makes veins constrict, via prostaglandin F2, thereby leading to leakage into capillary beds, due to the increased pressure in the capillaries.
Consequently, if a liquid has dynamic viscosity of n centiPoise, and its density is not too different from that of water, then its kinematic viscosity is around n centiStokes. For gas, the dynamic viscosity is usually in the range of 10 to 20 microPascal-seconds, or 0.01 to 0.02 centiPoise. The density is usually on the order of 0.5 to 5 kg/m^3.
[2] [3] [4] [12] Hypertension is a major cause of premature death worldwide. [13] High blood pressure is classified as primary (essential) hypertension or secondary hypertension. [5] About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors. [5]