Blood supply of the brain

Question 1

What are the branches of the internal carotid arteries important for the brain?

Answer 1

opthalmic artery, anterior choroidal artery, posterior communicating artery, anterior and middle cerebral artery

Question 2

What does the vertebrobasilar arterial system supply?

Answer 2

brainstem, cerebellum, spinal cord

Question 3

What are the vertebral branches of the vertebrobasilar system?

Answer 3

posterior and anterior spinal artery, posterior inferior cerebellar artery (PICA)

Question 4

What are the basilar branches of the vertebrobasilar system?

Answer 4

anterior inferior cerebellar artery (AICA), superior cerebellar artery, posterior cerebral arteries

Question 5

What is the circle of WIllis?

Answer 5

Interconnects the anterior and posterior circulations. Also intracranial-extracranial anastomoses (external-carotid artery, carotid basilar, carotid-vertebral)

Question 6

What are the cerebral vein valves?

Answer 6

There are none

Question 7

What do emissary veins do?

Answer 7

Connect extracranial veins with dural sinuses

Question 8

What is the path of drainage from the cerebral veins?

Answer 8

cerebral veins –> dural venous sinuses –> internal jugular veins and basilar venous plexus

Question 9

Describe the superficial veins

Answer 9

Superior: empty into the superior and inferior sagittal sinuses
Inferior: empty into the transverse and cavernous sinus

Question 10

Describe the deep veins

Answer 10

Cerebellar and brainstem, drain into deep (great vein of Galen), straight, transverse, and petrosal sinus

Question 11

Describe the routes of the veins and sinuses

Answer 11

1. superficial veins –> superior sagittal sinus –> confluence of sinus
2. Deep veins –> internal cerebral veins –> great vein –> straight sinus –> confluence of sinuses
3. Confluence of sinuses –> transverse sinuses

Question 12

How is blood flow controlled?

Answer 12

autoregulation: arterial and smooth muscle cell mediated
Metabolic: increased neuronal activity –> glutamate released –> astrocyte end feet receptors activated –> vasodilators factors released at end-feet applied to vessels
neural control: cerebral vessels innervated by autonomic fibers

Question 13

What are the brain barriers?

Answer 13

BBB (neurovascular unit), blood-csf barriers, arachnoid barries, blood-spinal cord barrier, blood-nerve barrier, blood-retinal barrier, blood-labyrinth barrier

Question 14

What is the BBB composed of?

Answer 14

Capillary endothelial cells, pericytes, astrocytes