BBB

Question 1

blood flow

Answer 1

internal carotid => ACA and MCA

basilar => 2 vertebral, SCA, AICA, PCA

vertebral => anterior spinal, posterior spinals, PICA

Question 2

cerebral blood supply

Answer 2

ACA - anterior, medial
PCA - posterior, medial, brainstem
MCA - lateral

Question 3

PICA stroke

Answer 3

Wallenburg syndrome/damaged medulla

• loss of pain/temp/proprio contralaterally
• loss of facial sensation ipsilaterally
• affects balance, pain, speech, taste

Question 4

circle of willis

Answer 4

-allows bypass of ACA/PCA occlusions

ACA => anterior communicating artery => posterior communicating artery => PCA

Question 5

ganglionic/perforating arteries

Answer 5

• tiny branches off larger CAs
• lenticulostriates
• supply deep structures (dien/telencephalon)
• occlusions prone to HTN and lipid disorders => selective neurodeficit
• perforated substance

Question 6

pathway of cerebral venous system

Answer 6

cerebral veins => dural sinuses => internal jugular vein + basilar plexus + epidural plexus of spinal cord

Question 7

pathway of superficial veins

Answer 7

superior veins => superior/inferior sagittal sinuses => confluence

inferior veins => transverse and cavernous sinuses => confluence

Question 8

pathway of deep veins

Answer 8

deep veins => internal cerebral veins => great vein of galen => straight sinus => confluence => transverse sinus

Question 9

great vein of galen

Answer 9

drains cerebellum and brainstem

Question 10

how do most venous occlusions occur

Answer 10

thrombosis (hypercoagulation, pregnancy)

Question 11

what is unique about the cranial venous system

Answer 11

valveless

many anastomoses

Question 12

how is blood flow controlled

Answer 12

• increased activity leads to increased flow
• neuron activity signals nearby artery to increase flow or increase delivery of certain substance
• perfusion to brain increases, perfusion to rest of body decreases
• autoregulation: via smooth muscle
• metabolic: increased activity => release of glutamate => astrocyte end feet receptors activated => vasodilators delivered by astrocyte

Question 13

what is normal blood perfusion

Answer 13

55mL blood/100g/minute

Question 14

describe abnormal blood perfusion

Answer 14

at 20ml => neurons shut down; brain can recover

at 10mL => necrosis; can’t rescue

Question 15

components of BBB

Answer 15

1. endothelial tight junctions
   - surface transporters control metabolite signaling
   - effected by neurohormones
2. astrocyte end feet prevent direct contact with neural tissue
3. pericytes - pleuripotent; immune function, angiogenesis
4. interneurons

Question 16

function of BBB

Answer 16

selectivity

allows function as neurovascular unit