Pathology Flashcards
what is protein aggregation?
accumulation of abnormally folded proteins
what are common mechanisms in degenerative disease?
chronic degeneration- protein aggregation, mitochondial impairement, synaptic dysfunction, transport/trafficking defects, oxidative damage, ageing
immunoglobulin structure
Y shaped containing 2 heavy and 2 light chains, constant and variable region with a hinge region
early pathology of MS
lots of myelin sheath and oligondendrocytes, ongoing disease, gradual neuroaxonal loss and impaired neuronal transmission
early lesions due to loss of BBB, immune cells enter causing tissue damage
what is a stroke?
the sudden onset of neurological signs or symptoms which last more than 24 hours and is due to a vascular cause
pathological conditions that cause strokes
- cerebral infarction - 85% of cases
-intracerebral hemorrhage - 10% of cases - subarachnoid hemorrhage
what is a TIA?
Trans ischemic attack- a sudden onset of neurological symptoms or signs due to a vascular cause that lasts less than 24 hours
what is a cerebral infarction?
necrosis due to inadequate blood supply to certain parts of the brain
mechanism of an ischemic stroke (cerebral infarction)
1) embolic infarction- most cerebral infarcts are due to emboli arising from an atherosclerotic plaque (thromboembolism)
2) thrombotic infarction- thrombotic occlusion of a vessel at the site of an atherosclerotic plaque (in situ thrombosis)
pathology of an infarction
occlusion of an artery causes infarction- all cells die
3-5 days later macrophages start to remove tissue debris
fluid filled cyst forms after 1 month to 5 years and all dead tissue removed
histological changes on an infarct
after 1-6 hours neurons appear red under microscopy due to neurons becoming hypoxic
At 24 hours- there is disintegration of brain tissue, necrosis is visible macroscopically
3-5 days- macrophages appear
when is brainstem affected in cerebral infarction?
occlusion of posterior inferior cerebellar artery
describe a watershed infarct
occurs when there is a global decrease in cerebral perfusion e.g. patient in shock, blood pressure is insufficient to properly perfuse the brain and the tissue that is perfused by the most distal vessels become hypoxic
describe a stroke due to a subarachnoid hemorrhage
due to rupture of of a saccular aneurysm of the circle of Willis or one of its branches, these aneursyms appear to be the result of congenital weakness in the arterial wall, over the years the wall branches out further and can rupture
What is Broca’s area?
a region in the left hemisphere that is involved with speech production
