Dear Cute. Remember while reading most of the answers above that giving common things big fancy names sounds impressive, but isn t very helpful, and does not mean the answer s correct. So here goes, trying to say it in simple language. The brain needs blood flow through fine tubes (capillaries) to nourish the cells. To cause blood to flow it needs a pressure difference between one end of the tube and the other, - just like a voltage, a current, and a wire. So the blood vessels in the brain are all pressurised in this way, and conduct blood flow back to the heart. The vessels, being so fine, are also vulnerable to rupture, (as is a balloon say), - and as one ages, the elasticity of the walls decreases, so any large increase in the pressure which the pumping action of the heart can burst the walls, and (a) cut off blood from where it should go, and (b) allow it to seep out and form pools and clots where it shouldn t. There! No quot;arteriosclerosisquot; or quot;ischemicquot; or quot;aneurismquot; needed, - just simple English. I would just add one thing. Most strokes are not the result of steady high pressures, but transient peaks added on to the normal ones, similar to the flashovers occurring in an electric circuit. So you can live for years with steady high pressures (systolic, diastolic, mean, and pulse-pressures) perfectly safely. It s the sudden bang on the head, or startling gun-shot, or emotional fright which is most likely to trigger a bursting of the blood vessels in the brain.
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Your question is somewhat unclear are you searching for information on hemorrhagic stroke? A hemorrhagic stroke, or cerebral hemorrhage, is a form of stroke that occurs when a blood vessel in the brain ruptures or bleeds. Like ischemic strokes, hemorrhagic strokes interrupt the brain s blood supply because the bleeding vessel can no longer carry the blood to its target tissue. In addition, blood irritates brain tissue, disrupting the delicate chemical balance, and, if the bleeding continues, it can cause increased intracranial pressure which physically impinges on brain tissue and restricts blood flow into the brain. In this respect, hemorrhagic strokes are more dangerous than their more common counterpart, ischemic strokes
Your question hits on a few things, let s discuss them. Hypertension is high blood pressure. Over time, high blood pressure damages the arteries. This damage manifests in different ways. First, it leads to atherosclerosis. Atherosclerosis can cause clots to form in vessels. If this occurs in the heart or the brain, a heart attack or stroke occurs, respectively. Atherosclerosis also weakens the walls of arteries. This can cause the walls to tear (a dissection), or can cause the artery to balloon out and possibly rupture (an aneurysm). Extremely high hypertension can effect these changes much more quickly. Malignant hypertension, as it s known, can cause vessels in the kidney and brain to scar down, blocking blood flow. In the brain, hypertension increases the risk for stroke. There are two types -- ischemic and hemorrhagic. Ischemic stroke (meaning quot;lack of oxygenquot;) occurs when a clot occludes one of the arteries in the brain, injuring that brain tissue. Hemorrhagic stroke occurs from bleeding into the brain. Since the brain is inside the skull, there s not a lot of room for extra blood to bleed out. If an artery in the brain hemorrhages from trauma or a ruptured aneurysm, the pressure squeezes off blood supply to the surrounding tissue. After either type of stroke, the injured brain tissue swells, further increasing the pressure in the skull. If the stroke and swelling are large enough, the pressure can even squeeze the brain through the bottom of the skull, where the spinal cord enters. This is called herniation, and is extremely dangerous.
Hypertension means high blood pressure within the arterial system, our bodies are used to a nice balance, when the increase in pressure occurs the arteries in the brain are directly connected to the heart via su[perior vena cava, so the react immediately by swelling, the brain is incapsulated by bone ( skull ) there isn t a lot of room for expansion therefore u feel a headache. An aneurysm simply is a weakening of arterial wall causing a bulge where more than normal amount of blood is present, they can rupture ususlly during a hypertensive crisis where the wall can no longer accomodate all the blood and pressure against its weak wall, however a ct can be helpful to diagnose the problem. the way a stroke happens is via a piece of plaque that is present in your arterial wall gets dislodged during a hypertensive crisis and lodges itsself in a smaller vessel such as the ones in your head causing a stroke or if it travel to your heart its called a heart attack. hope this helps.
The distribution of the common iliac artery is basically the pelvis and lower limb on the corresponding side. The external iliac artery arises from the bifurcation of the common iliac artery. It travels inferiorly, anteriorly, and laterally, making its ways to the lower limb: The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial compartment of the thigh. Risk factors for stroke include advanced age, hypertension (high blood pressure), previous stroke or TIA (transient ischaemic attack), diabetes mellitus, high cholesterol, cigarette smoking, atrial fibrillation, migraine with aura, and thrombophilia. In clinical practice blood pressure is the most important modifiable risk factor of stroke, however many other risk factors, such as cigarette smoking cessation and treatment of atrial fibrillation with anticoagulant drugs, are important. A hemorrhagic stroke, or cerebral hemorrhage, is a form of stroke that occurs when a blood vessel in the brain ruptures or bleeds. Subarachnoid hemorrhage (SAH) is bleeding into the cerebrospinal fluid (CSF) of the subarachnoid space surrounding the brain. The two most common causes of SAH are rupture of aneurysms from the base of the brain and bleeding from vascular malformations near the pial surface. Bleeding into the CSF from a ruptured aneurysm occurs very quickly, causing rapidly increased intracranial pressure. The bleeding usually only lasts a few seconds but rebleeding is common. Death or deep coma ensues if the bleeding continues. Hemorrhage from other sources is less abrupt and may continue for a longer period of time. SAH has a 40% mortality over 30 day period. The stroke is caused by several reasons. * Hemorrhagic stroke * Stroke related to cocaine use. * Stroke secondary to atherosclerosis. * Stroke secondary to atrial fibrillation. * Stroke secondary to cardiogenic embolism * Stroke secondary to carotid dissection. * Stroke secondary to carotid stenosis. * Stroke secondary to Fibromuscular dysplasia (FMD) * Stroke secondary to syphilis Please see the web pages for more details on Stroke.
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