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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]
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.
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.
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 ...
The narrowing of the lumen can decrease renal blood flow and hence glomerular filtration rate leading to increased renin secretion and a perpetuating cycle with increasing blood pressure and decreasing kidney function. [12] The brain is another organ where hyaline arteriolosclerosis occurs prematurely in patients with high blood pressure.
In the cases of cardiogenic shock resulting from heart failure or acute hemorrhagic shock caused by a large volume of blood loss, the body constricts peripheral vessels to reverse the low arterial pressure that causes inadequate tissue perfusion. [22] With vasodilatory shock, it is difficult for the peripheral vascular smooth muscle to ...
The causes of this condition are not well understood, but research suggests that it may be caused by a combination of hemodynamic and neurohumoral factors. [8]Some studies have found that orthostatic hypertension may be caused by increased vascular resistance, possibly due to excess plasma shifts or increased blood viscosity.
[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]