brain damage and neuroplasticity (4.5) Flashcards
brain damage
an injury that causes the destruction or deterioration of brain cells
major causes of brain injury (6)
tumors, vascular disorders (strokes), closed-head injuries, infections, neurotoxins, genetic factors
tumor
a mass of cells that grows independently of the rest of the body
cancerous vs non-cancerous tumors
cancerous: infiltrating; growing diffusely through surrounding tissue; malignant; invade/destroy neighboring tissue; can metastasize (spread); difficult to remove
non-cancerous: encapsulated; growing within a membrane; usually benign; cause damage by putting pressure on tissue; can often be surgically removed
symptoms of a brain tumor (4)
headache, seizures, vomiting, nausea
stroke
a sudden-onset cerebrovascular event that causes brain damage
infarct vs penumbra
infarct: an area of dead or dying tissue
penumbra: an at-risk area of dysfunctional tissue surrounding infarct
cerebral hemorrhage vs cerebral ischemia
hemorrhage: bleeding in the brain, typically caused when an aneurysm bursts
ischemia: disruption of blood supply due to thrombosis, embolism, or arteriosclerosis
thrombosis vs embolism vs arteriosclerosis
thrombosis: blood clot blocking blood flow at the site of formation (plaque rupture)
embolism: clot carried by blood from a large vessel to a small vessel; “a thrombus that has taken a trip”
arteriosclerosis: walls of blood vessel thicken and narrow the channel; can eventually lead to complete blockage of the blood vessels
glutamate theory (4)
(1) blood vessel becomes blocked
(2) neurons affected by the ischemia release excessive glutamate
(3) excessive glutamate binds to NMDA receptors, thus triggering an excessive influx of Na+ and Ca2+ ions into postsynaptic neurons
(4) influx eventually kills postsynaptic neurons, but first triggers the excessive release of glutamate from them, thus spreading the toxic cascade
contusions
injuries that involve damage to the cerebral circulatory system; causes internal bleeding and a hematoma (a localized collection of clotted blood; a bruise)
coup vs contrecoup
coup: contusions under the site of impact
contrecoup: contusions on the side opposite the impact
concussion
blow to the head resulting in no contusion, but a disturbance of consciousness; multiple may result in a dementia referred to as “punch-drunk syndrome”
bacterial vs viral infections
bacterial: often lead to cerebral abscesses (pockets of pus); may inflame meninges, creating meningitis; treated with antibiotics (i.e. penicillin)
viral: some preferentially attack neural tissues (i.e. rabies); others have no special affinity for it (i.e. mumps and herpes)
neurotoxins
may enter general circulation from the GI tract or lungs or through the skin
