brain damage Flashcards
what are the causes of brain damage
brain tumors cerebrovascular disorders closed-head injuries neurotoxins others
brain tumors
most brain tumours are infiltrating. they grow diffusely through surrounding tissue. malignant, difficult to remove or destroy.
what percent of brain tumours are metastatic
about 10% of brain tumours are metastatic-they originate elsewhere, usually the lungs
what is a neoplasm
is a mass of cells that grows independently of the rest of the body- a cancer
meningiomas
~20% of brain tumours are meningiomas- encased in meninges. encapsulated, growing within their own membranes. usually benign, surgically removable
stroke
a sudden onset cerebrovascular event that causes brain damage. cerebral hemorrhage or ischemia. 3rd leading cause of death and most common cause of adult disability
cerebral hemorrhage
bleeding in the brain, blood vessel ruptures. aneurysm or congenital
cerebral ischemia
disruption of blood supply. thrombosis, embolism, arteriosclerosis
aneurysm
a weakened point in a blood vessel that makes a stroke more likely. May be congenital or due to infection
thrombosis
plug forms
embolism
plug forms elsewhere and moves to the brain
arteriosclerosis
wall of blood vessels thicken, usually due to fat deposits
cerebral ischemia
damage does not develop immediately. most damage is a consequence of excess neurotransmitter release especially glutamate. blood deprived neurons become overactive and release glutamate. glutamate overactive its receptor, especially NMDA receptors leading to an influx of Na+ and Ca++
influx of Na+ and Ca++ triggers
the release of still more glutamate. a sequence of internal reactions that ultimately kill the neutron
ischemia induced brain damage
takes time. does not occur equally in all parts of the brain. mechanisms of damage vary with the brain structure affected
closed head injuries
brain injuries due ti blows that do not penetrate the skull- the brain collides with the skull
types of closed head injuries
coup injuries contrecoup injuries contusions cerebral edema concussion
coup injuries
injuries in the same side of the brain as the blow
contrecoup injuries
contusions are often on the side of the brain opposite to the blow
contusions
closed head injures that involve damage to the cerebral circulatory system. a hematoma, a bruise, forms
cerebral edema
brain swelling
concussion
when there is a disturbance of consciousness following a blow to the head and no evidence of structural damage
neurotoxins
may enter general circulation from the GI tract, lungs or through the skin. some antipsychotic drugs produce a motor disorder caused trade dyskinesia. recreational drugs cause brain damage. some neurotoxins are endogenous.
toxic psychosis
chronic psychosis produced by a neurotoxin