Cerebrovascular system

Question 1

Facts about blood supply to the brain

blood provides brain cells with ?

blood removes ?

average of ? is pumped into the brain per minute

about … of the body’s blood and … percent of its oxygen goes to the ?
-the brain is only .. of the body’s weight

without adequate blood supply the brain cannot ?

Answer 1

nutrition

waste and CO2 from nerve cells

750 ml

-20% /25% / brain at any one time

2%

function properly and cell bodies can be permanently damaged

Question 2

the brain uses more then ?

Answer 2

20% oxygen and metabolized glucose (muscles store glycogen but brain can’t so it needs constant circulation to meet its very high metabolic needs)

Question 3

Without nourishment

Answer 3

brain cells die

Question 4

Vascular network:

arteries: carry
capillaries:
veins: return
heart and lungs: … is pumped from the ? which is then diverted back to the ?

Answer 4

oxygenated blood to the brain
terminal extension of arterial network
deoxygenated blood back to heart

deoxygenated blood/ lungs for reoxygenation/heart to b pumped throughout the body via arteries

Question 5

Two main systems that supply the brain with blood:

they meet in

Answer 5

carotid system
vertebral basilar system

circle of willis

Question 6

Cerebrovascular Supply

2 arterial systems supply the brain with blood:

Answer 6

carotid system: anterior supply

vertebral basilar system: posterior supply

Question 7

Levels of the Cerebrovascular System:

from inferior to superior (heart to cortex)

level 1

level 2

level 3

Answer 7

inferior to circle of Willis
Supply the Circle of Willis

Circle of Willis

Superior to and arising from the Circle of Willis

Question 8

Carotid System:

the common carotid artery ascends

the common carotid bifurcates into

external carotid artery

internal carotid artery

Answer 8

nourishes facial muscles, oral, orbital and nasal cavities

supplies blood to brain
bifurcates to form 2 cortical arteries on each side
-anterior cerebral artery (ACA)
-Middle cerebral artery (MCA)

Question 9

Vertebral Basilar System:

Two vertebral arteries arise from?

the vertebral arteries merge to form a ?

-
-

terminates at the ?
-eventually bifurcates to form ?

Answer 9

subclavian arteries

single basilar artery at the level of the caudal pons

many branches supplying

• spinal cord
• brainstem
• cerebellum

circle of willis
the posterior cerebral arteries (PCA’s)

Question 10

Circle of Willis:
named for ?
joins the brain’s ?
allows for ? int he event that

Answer 10

17th century anatomist/physician Thomas willis

two arterial sources of blood (anastomoses)

collateral blood flow/an artery is blocked

Question 11

Circle of Willis

Anastomotic connection between the ?

• what surface of the brain
• provides

2 
2
1
2
2

2 types of arteries arise from the Circle of Willis

Answer 11

carotid and vertebral basilar arterial systems

• ventral
• collateral circulation

middle cerebral arteries 
anterior cerebral arteries  
anterior communicating artery 
posterior cerebral arteries 
posterior communicating arteries 

cortical: supply external brain structures
central: supply internal brain structures

Question 12

Blood Supply to the Brain

These arteries are in the?and also continue

It is important to distinguish when they are ? and when they are ?

• this helps us to
• this helps us

Answer 12

Circle of Willis/ superiorly from the Circle of Willis

• anterior cerebral Artery
• Middle Cerebral Artery
• Posterior Cerebral Artery

in/at the level of the Circle of Willis / above/outside the Circle of Willis

define the Circle of Willis
understand the effects of interrupted blood supply

Question 13

Blood Supply to the Brain

blockage in branches of basilar artery

circle of willis: if blockage in anterior comm. artery or posterior comm. artery within level of Circle of willis:

blockages in cerebral arteries

Answer 13

brainstem or cerebellar stroke

blood can circulate to other areas

higher up - cerebral stroke

Question 14

Superior to the circle of Willis the brain regions are supplied by main cortical arteries in each hemisphere

Answer 14

anterior cerebral artery
middle cerebral artery
posterior cerebral artery

Question 15

Anterior Cerebral Artery

mainly supplies the ?
clinical signs of ACA disruption:
-
-
-

Answer 15

medial surfaces of the frontal and parietal lobes

• sensory loss and paralysis in the legs feet and toes
• prefrontal lobe symptoms (disordered cognition)
• psychosocial symptoms

Question 16

Middle Cerebral Artery (MCA)
largest
supplies the ?
-important ?

supplies the ?
-via the ?

clinical signs of MCA disruption 
-
-
-
-
-

Answer 16

cortical artery

entire lateral surface of the cerebrum

• speech, language and sensorimotor areas
• brocas area, wernickes area, primary auditory cortex, somatosensory cortex, primary and pre motor cortex, prefrontal cortex, supramarginal and angular gyri

basal ganglia and diencephalon
-lateral and medial lenticulostriate branches given off by the MCA

• Contralateral hemiplegia and sensory impairment
• aphasia
• apraxia
• temporospatial deficits
• motor impairment

Question 17

Posterior Cerebral artery:
supplies
supplies

clinical signs of PCA disruption

Answer 17

medial and inferior temporal lobe
inferior and medial occipital lobe

visual disturbances
memory impairment

Question 18

Central Arteries:
branches that arise from ?
penetrate the ?
-supply
-overlapping blood supply facilitates

Answer 18

proximal portions of cortical arteries or from the circle of willis

interior surface of the brain

• subcortical structures
• development of anastomosis

Question 19

Venous drainage of brain:

venous supply much less susceptible to? due to ?

internal veins deliver blood to ? which then drain into

Answer 19

internal veins, venous sinuses, internal jugular veins, heart

injury/ much lower blood pressure

venous sinuse between layers of the dura mater/jugular veins

Question 20

Blood-Brain barrier

prevents ?
-although not all

consists of ? and the ?

• capillaries have
• end feet of astrocytes ?

in most parts fo the body almost anything can pass through ? not so in?

Answer 20

harmful substances in blood from getting into brain tissue
-psychoactive drugs

endothelial cells in blood vessels / astrocytes immediately surrounding blood vessels

tight junctions between endothelial cells

wrap around capillaries to reinforce

capillary walls into extracellular space of surrounding tissue/ brain

Question 21

Threats to BBB

Answer 21

stroke
tumor
infection