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The increase in pulse pressure may result in increased damage to blood vessels in target organs such as the brain or kidneys. [23] [24] This effect may be exaggerated if the increase in arterial stiffness results in reduced wave reflection and more propagation of the pulsatile pressure into the microcirculation. [23]
Causes range from non-serious to potentially fatal. [1] There are three broad categories of causes: heart or blood vessel related; reflex, also known as neurally mediated; and orthostatic hypotension. [1] Issues with the heart and blood vessels are the cause in about 10% and typically the most serious while neurally mediated is the most common. [1]
The underlying mechanism involves the nervous system slowing the heart rate and dilating blood vessels, resulting in low blood pressure and thus not enough blood flow to the brain. [2] Diagnosis is based on the symptoms after ruling out other possible causes. [3] Recovery from a reflex syncope episode happens without specific treatment. [2]
Symptoms associated with central nervous systems disorders are classified into positive and negative categories. Positive symptoms include those that increase muscle activity through hyper-excitability of the stretch reflex (i.e., rigidity and spasticity) where negative symptoms include those of insufficient muscle activity (i.e. weakness) and reduced motor function. [5]
The narrowing of blood vessels leads to an increase in peripheral resistance, thereby elevating blood pressure. While vasoconstriction is a normal and essential regulatory mechanism for maintaining blood pressure and redistributing blood flow during various physiological processes, its dysregulation can contribute to pathological conditions.
It affects all of the vessels: very small blood vessels (capillaries), medium-size blood vessels (arterioles and venules), or large blood vessels (arteries and veins). If blood flow in a vessel with vasculitis is reduced or stopped, the parts of the body that receive blood from that vessel begins to die, resulting in a stroke.
Vasodilation plays a major role in immune system function. Wider blood vessels allow more blood containing immune cells and proteins to reach the infection site. Vasodilation occurs as part of the process of inflammation, which is caused by several factors including presence of a pathogen, injury to tissues or blood vessels, and immune ...
The main cause of endothelial dysfunction is impaired bioavailability of nitric oxide. [ 1 ] In addition to acting as a semipermeable membrane , the endothelium is responsible for maintaining vascular tone and regulating oxidative stress by releasing mediators, such as nitric oxide, prostacyclin and endothelin , and by controlling local ...