Flashcards in blood perfusion Deck (53):
1
blood - cortical distribution - arteries and what the supply
1. anterior cerebral artery --> anteriomedial surface of the cortex
2. middle cerebral artery --> lateral surface of the cortex
3. posterior cerebral artery --> posterior and inferior surface
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anterior cerebral artery supplies
anteriomedial surface of the cortex
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middle cerebral artery supplies
lateral surface of the cortex
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posterior cerebral artery supplies
posterior and inferior surface
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watershed zones of the brain - areas
- between anterior cerebral/middle cerebral arteries
- between posterior cerebral/middle cerebral arteries
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watershed zone are in danger to be damaged under / lesions
severe hypotension --> 1. upper leg/upper arm weakness 2. defects kn higher order visual processes
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Basilar artery is formed by
anastomosis of right and left vertebral arteries
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cerebellar arteries
1. superior cerebellar
2. anterior inferior cerebellar
3. posterior inferior cerebellar
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source of posterior inferior cerebellar arteries
branch of vertebral arteries
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source of anterior inferior cerebellar arteries
branch at the formation of basilar artery (from right and left vertebral arteries anastomosis)
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source of superior cerebellar arteries
branch just before the end of basilar artery
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basilar artery branches
1. anterior inferior cerebellar (at the beginning)
2. pontine arteries
3. superior cerebellar
4. basilar artery becomes left and right posterior cerebral artery
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circle of willis - definition
system of anastomoses between anterior and posterior blood supplies to brain
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source of posterior cerebral artery
at the and of basilar artery (basilar artery becomes right and left posterior cerebral artery)
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source of middle cerebral artery
internal carotid is divided to middle and anterior cerebral artery
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source of anterior cerebral artery
internal carotid is divided to middle and anterior cerebral artery
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area of circle of wills (anatomy)
near optic chiasm
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communicating between cerebral arteries
1. anterior communicating --> between left and right cerebral artery
2. posterior communicating --> posterior cerebral with internal carotid (just before the division of middle and anterior cerebral artery)
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source of anterior spinal artery
from both vertebral arteries (2 vertebral arteries --> 1 anterior spinal artery)
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first branches of middle cerebral artery
1. anterior choroidal artery
2. Lenticulo-striate arteries
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Brain perfusion relies on tight ...
auto-regulation
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auto-regulation - Cerebral perfusion is primarily driven by
1. PCO2 (primarily)
2. PO2 (in severe hypoxia)
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auto-regulation - hypoxemia increases cerebral perfusion pressure when
P02 is less than 50 mm Hg
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autoregulation - relationship between PO2 and cerebral blood flow
P02 increases cerebral blood flow (until P02=50 mmHg)
PO2>50 --> plateau of cerebral blood flow
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autoregulation - relationship between PCO2 and cerebral blood flow
cerebral perfusion pressure increases with PCO2 until PCO2=90 mmHg
at PCO2>90 --> plateau of cerebral blood flow
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pathophysiology of fainting in panic attack
increased RR --> decreased PCO2 --> decreased cerebral blood flow --> fainting
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therapeutic hyperventilation of acute cerebral edema (stroke, trauma)
hyperventilation --> decreased PCO2--> vasoconstriction --> decreased cerebral blood flow --> decreased intracranial pressure
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CPP
cerebral perfusion pressure
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CPP (cerebral perfusion pressure) = .. (and explanation)
CPP = MAP - ICP
cerebral perfusion relies on pressure gradient between mean arterial pressure and intracranial pressure
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CCP (cerebral perfusion pressure)? if decreased MAP
decreased
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CCP (cerebral perfusion pressure)? if increased ICP
decreased
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if CCP=O --> ..
no cerebral perfusion --> brain death
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circle of Willis - anterior vs posterior circulation (which arteries)
posterior: basilar artery - posterior cerebral arteries
anterior: anterior and middle cerebral arteries, internal carotid
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dural venous sinuses? and area
large venous channels that run through the dura
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dural venous sinuses - flows? (function)
drain blood from cerebral vein and receive CSF from
arachnoid granulation
they empty into internal jugular vein
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Arachnoid granulations are
growths of arachnoid membrane into the dural sinuses through which CSF enters the venous system.
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dural venous sinuses empty into
internal jugular vein
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dural venous sinuses drain blood from
cerebral vein
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dural venous sinuses - examples (types)
1. superior sagittal (οβελιάιος) sinus
2. inferior sagital sinus
3. straight sinus (ευθής)
4. occipital sinus
5. transverse sinus (εγκάρσιος)
6. sphenoparietal sinus
7. cavernous sinus
8. sigmoid sinus
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watershed zones --> damage in severe hypotenesion --> (clinical manifestation)
1. upper leg/upper arm weakness
2. defects in higher-order visual processing
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brain is supplied by (generally)
1. internal carotid arteries (anteriorly)
2. basilar artery (posteriorly)
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main location of CSF return via arachnoid granulations
superior sagittal sinus
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straight sinus is composed by
anastomosis of inferior sagital sinus AND great cerebral vein of Galen
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anastomosis of inferior sagital sinus AND great cerebral vein of Galen -->
straight sinus
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confluence of the sinuses (what terminals their and what starts from their)
1. straight sinus (finish)
2. superior sagittal sinus (finish)
3. occipital sinus (finish)
4. (2) transverse sinus (start)
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confluence of the sinuses (what terminals their)
1. straight sinus
2. superior sagittal sinus
3. occipital sinus
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confluence of the sinuses (what starts from their)
transverse sinus (start)
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transverse sinus - fate
is becoming sigmoid sinus and then internal jugular vein
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carvenous sinus - composed by / fate
it is composed by sphenparietal sinus superior and ophalmic vein
flows into transverse sinus
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sphenoparietal sinus - direction
it connects supperior sagital sinus with carvenous sinus
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Homonculus?
topographic representation of motor and sensory areas in the cerebral cortex
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Homonculus - distorted appearance is due to
certain body regions being more richly innervated and thus having increased cortical representation
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