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Stroke is a serious condition of blood vessel disorder caused by the stop of blood supply to the brain. Brain cells with ceased oxygen supply from blood will die in millions per second. [ 14 ] Not only is it one of the major causes of death around the world, it is also the cause of permanent disability.
Over time, this increased workload may cause left ventricular hypertrophy and left ventricular remodelling, which can lead to heart failure. [25] The increased workload may also be associated with a higher heart rate, a proportionately longer duration of systole and a comparative reduction of duration of diastole. [ 26 ]
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in controlling hemorrhage and reducing acute blood loss.
For the thin-walled assumption to be valid the vessel must have a wall thickness of no more than about one-tenth (often cited as one twentieth) of its radius. The cylinder stress, in turn, is the average force exerted circumferentially (perpendicular both to the axis and to the radius of the object) in the cylinder wall, and can be described as:
Brain ischemia has been linked to a variety of diseases or abnormalities. Individuals with sickle cell anemia, compressed blood vessels, ventricular tachycardia, plaque buildup in the arteries, blood clots, extremely low blood pressure as a result of heart attack, and congenital heart defects have a higher predisposition to brain ischemia in comparison to the average population.
Stroke is caused by marked narrowing or closure of arteries going to the brain; lack of adequate blood supply leads to the death of the cells of the affected tissue. [ 26 ] Peripheral arteries , which supply blood to the legs, arms, and pelvis, also experience marked narrowing due to plaque rupture and clots.
This is caused by an increase in the pressure of the blood flowing through the vessels. Hypertension can lead to heart failure and stroke. Aspirin helps prevent blood clots and can also help limit inflammation. [37] Vasculitis is inflammation of the vessel wall due to autoimmune disease or infection.
[21] [22] Thrombi can occlude veins (venous thrombosis) or arteries (arterial thrombosis). The etiology of thrombosis is described by Virchow's Triad, which includes hemostasis, vascular wall damage, and hypercoagulability. [21] Arterial thromboses significantly narrow or completely block arterial blood flow and oxygen delivery to tissues.