NeuroplasiticitychandCerebralHemispheresch.pptVIP

Neuroplasiticitych. 10and Cerebral Hemispheresch. 16 Neuropsychological Disorders, Damage to CNS, and Neuroplasticity Ch. 10 Outline Causes of Brain Damage Neuropsychological Diseases Neural Damage: Degeneration, Regeneration, Reorganization, and Recovery Causes of Brain Damage Tumors Group of cells growing independently of the rest of the body; tumor can be encapsulated or infiltrating; it can be benign or malignant Metastatic tumors originate in one organ and spread to another; the symptoms of multiple brain tumors are often the first signs of lung cancer 20% of brain tumors are meningiomas that grow in the meninges; they are encapsulated and benign Cerebrovascular Disorders Stroke is the common term May be due to cerebral hemorage, the bursting of aneuryms (balloon-like dilations of weak areas of blood vessels) Cerebrovascular Disorders Strokes are also caused by a cerebral ischema, a disruption of blood supply to an area of the brain In thrombosis, a plug becomes lodged at the site of formation; the plug may be due to a blood clot, fat, oil, cancerous cells, air bubbles In embolism a plug travels and becomes lodged in a smaller blood vessel In arteriosclerosis the blood vessel walls thicken and the space inside narrows from accumulation of fat Cerebrovascular Disorders The brain damage caused during an ischemic episode is believed to be due to an excessive release of excitatory amino acids Glutamate, the brain’s most prevalent excitatory neurotransmitter, is released in excessive quantities when blood vessels are blocked Cerebrovascular Disorders The excessive glutamate overactivates glutamate receptors on the postsynaptic membrane sites thus too many Na+ and Ca++ ions are allowed to enter the postsynaptic neuron; this overabundance of ions triggers either More excessive release of glutamate, causing a cascade of this toxic effect Triggers a sequence of reactions that kills the postsynaptic neuron Cerebrovascular Disorders The brain damage caused by ische