Psych 10 - Brain Damage and Neuroplasticity (240-267) - A...

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Brain Damage and Neuroplasticity (240-267) - A tumor, or neoplasm is a mass of cells that grows independently of the rest of the body. About 20% of tumours found in the human brain are meningiomas, tumors that grow between the meniges, the three membranes that cover the CNS. All meningiomas are encapsulated tumours, those that grow within their own membrane (easily detectable on CT scan), they can influence the function of the brain only by the pressure they exert on the surrounding tissue and they are almost always benign. Benign refers to tumours that are surgically removable with little risk of further growth in the body. Most brain tumours are infiltrating meaning that they grow diffusely through surrounding tissue and are usually malignant meaning they are difficult to remove or destroy, and any cancer tissue that remains after surgery continues to grow. - About 10% of brain tumours do not originate in the brain, they grow from infiltrating cells that are carried to the brain by the bloodstream, and these are metastic tumours. Metastasis refers to the transmission of disease from one organ to another. Neuromas are tumours that grow on nerves or tracks. Strokes are sudden-onset cerebrovascular disorders that cause brain damage; it is the 3 rd leading cause of death and the most common cause of adult disability. Common consequences are amnesia, aphasia, paralysis, and coma. The area of dead or dying tissue is called an infarct. Surrounding the infarct is a dysfunctional area called the penumbra. The goal of treatment after stroke is to save this tissue. - Cerebral hemorrhage (bleeding in the brain) occurs when a cerebal blood vessel ruptures and blood seeps into the surrounding neural tissue and damages it. Bursting aneurysms are a common cause of intracerberal hemorrhage. An aneurysm is a pathological balloonlike dilation that forms in the wall of an artery at a point where the elasticity of the artery wall is defective. Aneuryms can be congenital (present at birth) or can result from exposure to vascular poisons or infection. Cerebral ischemia is a disruption of the blood supply to an area of the brain. The main causes of cerebral ischemia include thombosis, when a plug called a thrombus is formed and blocks blood flow at the site of its formation, and embolism, when the plug called an embolus is carried by the blood from a larger Bessel where it was formed to a smaller one where it becomes lodged. Also arteriosclerosis is when the walls of blood vessels thicken and the channels narrow, usually as a result of fat deposits, this narrowing can eventually lead to complete blockage of the blood vessels. Much of the brain damage associated with stroke is a consequence of excessive release of excitatory amino acid neurotransmitters, in particular glutamate, the brains most prevalent excitatory neurotransmitter. - After a blood vessel becomes blocked, many of the blood-deprived neurons become overactive and release
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This note was uploaded on 02/09/2012 for the course PSYCH 2220 taught by Professor Culham during the Spring '11 term at UWO.

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Psych 10 - Brain Damage and Neuroplasticity (240-267) - A...

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