Investigating The Physiological Phenomena Of The Heart - amazonia.fiocruz.br

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A stroke is a medical condition in which poor blood flow to the brain causes cell death. The main risk factor for stroke is high blood pressure. Prevention includes decreasing risk factors, surgery to open up the arteries to the brain in those with source carotid narrowingand warfarin in people with atrial Physiologicla.

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Strokes can be classified into two major categories: ischemic and hemorrhagic. Bleeding can develop inside areas of ischemia, a condition known as "hemorrhagic transformation.

In Physiologifal s the World Health Organization defined stroke as a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours", [19] although the word "stroke" is centuries old. This definition was supposed to reflect the reversibility of tissue damage and was devised for the purpose, with the time frame of 24 hours being chosen arbitrarily. The hour limit divides stroke from transient ischemic attackwhich is a related syndrome of stroke symptoms that resolve completely within 24 hours.

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In an ischemic stroke, blood supply to part of the brain is decreased, leading to dysfunction of the brain tissue in that area. There are four reasons why this might happen:. There are various classification systems for acute ischemic stroke.

These four entities predict the extent of the stroke, the area of the brain that is affected, the underlying cause, and the prognosis. There are two main types of hemorrhagic stroke: [28] [29].

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The above two main types of hemorrhagic stroke are also two different forms of intracranial hemorrhagewhich is the accumulation of blood anywhere within the cranial vault ; but the other forms of intracranial hemorrhage, such as epidural hematoma bleeding between the skull and the dura materwhich is the thick outermost layer of the meninges that surround the brain and subdural hematoma bleeding in the subdural spaceare not considered "hemorrhagic strokes". Hemorrhagic strokes may occur on the background of alterations to the blood vessels in the brain, such as cerebral amyloid angiopathycerebral arteriovenous malformation and an intracranial aneurysm https://amazonia.fiocruz.br/scdp/essay/writing-practice-test-online/literature-review-the-great-thing-about-it.php, which can cause intraparenchymal or subarachnoid hemorrhage.

In addition to neurological impairment, hemorrhagic strokes usually cause specific symptoms for instance, subarachnoid hemorrhage classically causes a severe headache known as a thunderclap headache or reveal evidence of a previous head injury.]