Blood Supply and Hemorrhage Flashcards
What is ischemic penumbra?
when a focal ischemia not only results in neuronal injury to the central core territory of the arterial supply but also varying degrees of dysfunction to the potentially viable tissue in the surrounding marginal area
what is the regional cerebral blood flow range that will result in an ischemic penumbra?
10-20 ml/ 100 gm tissue/ min
what areas of the brain are consistently damaged in severe ischemic injury?
distal branches of the cerebral arteries and particular neuronal populations (pyramidal cells of the hippocampus)
what is stroke therapy directed at rescuing?
the ischemic penumbra
what specific drugs might prevent further neuronal damage?
calcium channel and NMDA receptor blocking drugs
the internal carotid and vertebral arteries pierce the dura and course in what?
the subarachnoid space
as the branches of the internal carotid artery penetrate into the substance of the brain, what are they progressively surrounded by?
perivascular space (Virchow-robin space)
where are the terminations of the ICA, vertebral artery, and the circle of willis located?
in the subarachnoid space
infarction in the anterior choroidal artery territory may result in what?
triad of hemiplegia, hemianesthesia, and contralateral hemianopia (anterior choroidal artery syndrome)
which artery has the highest incidence of cerebral aneurysms?
ACA
what is the terminal branch of the ICA?
the anterior cerebral artery (ACA)
what supplies the premotor and prefrontal cortices and the broca’s speech area in the dominant hemisphere?
frontal branches of the MCA
what does thrombosis of the MCA result in?
expressive or broca’s aphasia
what does obstruction of the MCA artery lead to?
wernicke’s aphasia
How do you get central cord syndrome?
if there is a disruption of blood flow to the anterior spinal artery
what does central cord syndrome lead to?
central necrosis and cavitation of the spinal cord–> development of a syrinx
what is the major supply to the inferior 2/3 of the spinal cord?
the great anterior artery of Adamkiewiez
What is at risk to be compromised secondary to a thoracolumbar fracture or surgical repair of an AAA?
the great anterior artery of adamkiewiez
what does thrombosis of the PICA result in?
lateral medullary (wallenburg) syndrome
What artery is responsible for supplying the primary visual cortex?
the posterior cerebral artery (PCA)
rupture of the anterior communicating artery results in the presence of blood where?
in the subarachnoid space
the superior sagittal sinus usually empties into what?
the right transverse venous sinus
what does thrombosis of the posterior portion of the superior venous sinus or right transverse venous sinus result in?
cortical ischemia and/or necrosis
what does thrombosis of the posterior portion of the straight venous sinus or left transverse venous sinus result in?
ischemia and/or necrosis of structures in the deep cerebrum- usually fatal
what are herniations of the brain secondary to?
a unilateral increase in the volume (mass effect)
what type of herniation causes a midline shift?
Falx herniation
what herniation compresses and displaces the midbrain and is caused by profuse, high-pressured bleeding that rapidly expands the epidural space
a tentorial/ uncal herniation
what herniation is caused by space expanding or occupying masses in the posterior cranial fossa?
tonsillar herniation
what herniation is seen in arnold-chiari malformation?
tonsillar herniation
a fracture at the pterion may rupture what?
the middle meningeal artery
rupture of the middle meningeal artery would result in what?
an epidural hematoma
what causes a subdural hematoma?
head trauma may cause the cerebral veins to rupture as they cross the subdural space. Blood seeps out of the ruptured veins and slowly develops a space-occupying heomatoma in the subdural space
how is a subarachnoid hemorrhage indicated?
by the presence of erythrocytes in the CSF
increase in the intracranial volume can cause what?
subfalcine herniation
