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A Hollenhorst plaque (also known as a retinal cholesterol embolus) is a cholesterol embolus that is seen in a blood vessel of the retina.It is usually found when a physician performs ophthalmoscopy, during which a plaque will appear as a small, bright crystal that is refractile (reflects the light from the ophthalmoscope) and yellow. [1]
Excessive reduction in blood pressure can precipitate coronary, cerebral, or kidney ischemia and, possibly, infarction. [citation needed] A hypertensive emergency is not based solely on an absolute level of blood pressure, but also on a patient's baseline blood pressure before the hypertensive crisis occurs.
Magnetic resonance angiography (MRA) is a group of techniques based on magnetic resonance imaging (MRI) to image blood vessels. Magnetic resonance angiography is used to generate images of arteries (and less commonly veins) in order to evaluate them for stenosis (abnormal narrowing), occlusions, aneurysms (vessel wall dilatations, at risk of rupture) or other abnormalities.
Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). [3] [4] Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue i.e. hypoxia and ...
Emboli break off from the plaque and travel through the circulation to blood vessels in the brain. As the vessels get smaller, an embolus can lodge in the vessel wall and restrict the blood flow to parts of the brain. This ischemia can either be temporary, yielding a transient ischemic attack (TIA), or permanent resulting in a thromboembolic ...
Buerger's disease – inflammation and swelling in small blood vessels, causing the vessels to narrow or become blocked by blood clots. [18] Raynaud syndrome – a peripheral vascular disorder that causes constriction of the peripheral blood vessels in the fingers and toes when a person is cold or experiencing stress. [19]
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]
Return of systemic blood to the heart is impeded by the pressure inside the chest. The output of the heart is reduced, and stroke volume falls. This occurs from 5 to about 14 seconds in the illustration. The fall in stroke volume reflexively causes blood vessels to constrict with some rise in pressure (15 to 20 seconds).