What percentage of cardiac output goes to the brain?
What percentage of O2 utilization goes to the brain?
15%
20%
What is the blood flow to the brain?
50ml/100g/min
800ml/min
Gray 70-80
White 30
THRESHOLD FOR DAMAGE: <15ml/100g/min
What are the segments of the internal carotid artery?
Cervical Petrosal Laceral Cavernous Clinoid Ophthalmic Communicating
- What is the first intracranial branch of the ICA?
2. What branch of the ICA comes after the ICA emerges from the cavernous sinus
- Ophthlamic that supplies the optic nerve and gives rise to the central artery of the retina
- Anterior choroidal artery
Enumerate the branches of the ACA?
- Recurrent artery of Heubner
- Orbitofrontal artery
- Frontopolar artery
- Pericallosal artery: branches are callosomarginal and the paracentral arteries– until it terminates as the precuneal branch
How does the pericallosal artery terminate?
As the precuneal branch
What are segments of the MCA?
What are the branches of MCA?
M1: Sphenoid/ horizontal segment
M2: Sylvian/ insular segment
M3: Opercular segment
M4: Cortical segment
Anterior: OPRA Orbitofrontal, Prerolandic, Rolandic, Anterior temporal
Posterior: TAPAP Temporopolar, anterior temporal, Posterior temporal, angular, posterior parietal
Posterior cerebral artery branches–
Lateral
Medial
Lateral: Calcarine branch, Parietooccipital branch
Medial: Anterior temporal branch, Posterior temporal branch
Bilateral occlusion of the PCA will result in:
- Prosopagnosia (loss of facial recognition)
- Achromatopsia (loss of color vision)
Macula also has supply from MCA
NB: Inferomedial temporo occipital region results in both deficits
What can be compressed during uncal herniation?
PCA resulting in cortical blindness
What percentage of people will have a complete Circle of Willis?
20%
What characteristic of cerebral vessels will dfx them from normal vessels?
- Thinner walls
- Absent external elastic lamina
- Presence of astrocytic processes
- Presence of a perivascular reticular sheath consisting of arachnoid trabeculae
What are the two major sites of ECA ICA anastomoses?
- ECA with ophthamic a
- Rete mirabile: vessels that connect meningeal and ethmoidal branches of external carotid arteries with leptomeningeal arteries
Where do the ff drain?
- Superior anastomotic vein of Trolard/superior cerebral group
- Inferior anastomotic vein of labbe/inferior cerebral group
- Sylvian vein
- Superior sagittal sinus
- Transvers sinus/ cavernous sinus
- Cavernous sinus– the SV connects with Trolard and Labbe as well!
What are the two veins that form the internal cerebral vein?
What are the two veins that form the vein of Galen?
What are the two veins that form the straight sinus?
What are the two veins that form the internal cerebral vein? Terminal vein (Thalamostriate v.) + Septal v.
What are the two veins that form the vein of Galen?
Basal vein of rosenthal and internal cerebral vein
What are the two veins that form the straight sinus? Vein of Galen and inferior sagittal sinus
What will the ff do to cerebral blood flow?
- CO2 high
- pH low
- CO2 high: Vasodilation
2. pH low: Increase blood flow
What is the effect of the ff neuropeptides on cerebral vessels?
- Neruopeptide Y
- CGFP, VIP, Substance P, Calcitonin gene related peptide
- Vasodilate: Neruopeptide Y
2. Vasoconstrict: CGFP, VIP, Substance P, Calcitonin gene related peptide
What side of the brain is damaged with topographagnosia? (inability to interpret maps)
Right non-dominant
What area is likely involved with sphincter control disorders in bilateral ACA infarcts?
Paracetnral lobule
Why does transient monocular blindness occur with an ICA infarct?
Amaurosis fugax occurs because of involvement of the opthalmic artery
Why can there be hemianopia with anterior choroidal syndrome?
Invovlement of the retrolenticular part of the internal capsule or the lateral geniculate body
- Balint and Anton’s syndrome both result with occlusion of?
- Pure alexia without agrapha occurs with damage and sparing of what structures?
- Both PCAs.
- LEFT medial occipitotemporal area and splenium of the CC. Patient can write because left brain is working and write hand is used to write BUT patient can read because intact occipital lobe is on the right side BUT info can’t cross to the other side because of the dead splenium
angular gyrus needs to be SPARED.
Occurs with unilateral PCA stroke on the dominant side
What are the areas involved?
- Ataxic hemiparesis?
- Dysarthria clumsy hand syndrome?
- Etat lacunaire syndrome?
- Ataxic hemiparesis? Basis pontis, IC posterior limb, red nucleus plus cerebral peduncle
- Dysarthria clumsy hand syndrome? Basis pontis
- Etat lacunaire syndrome? many lacunes in the frontal lobe
