Lecture 4 - Blood Supply Flashcards

1
Q

Unconsciousness occurs in - seconds if blood flow to brain is completely interrupted.

A

5-10

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2
Q

Blood flow to CNS delivers ___, ____, and ___.

Blood flow to CNS removes ____, ____, and ____.

A

delivers: O2, glucose, nutrients

removes CO2, lactic acid, metabolites

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3
Q

The ____ supplies the anterior circulation. The _____ supplies the posterior circulation.

A

paired internal carotid arteries, paired vertebral arteries

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4
Q

What do the paired internal carotid artery pass through to enter the cranium?

A

carotid canal

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5
Q

How do the paired vertebral arteries pass through to enter the cranium?

A

foramina transverseria to the foramen magnum

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6
Q

Trace the path of the anterior supply from the heart to just as it enters the cranium.

A

Right (aorta -> brachiocephalic artery -> right common carotid artery -> internal carotid artery -> carotid canal)
Left (aorta -> left common carotid artery -> internal carotid artery ->carotid canal)

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7
Q

what are the 2 divisions of the common carotid artery?

A

internal & external

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8
Q

External carotid artery supplies what 3 structures?

A

face, scalp and meninges

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9
Q

Which branch of the external carotid artery runs in epidural space between the cranium and the periosteal layer of the dura?

A

middle meningeal artery

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10
Q

The middle meningeal artery enters the skull through what?

A

foramen spinosum

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11
Q

What does the middle meningeal artery supply? Rupture of the middle meningeal artery would give rise to hemorrhage where?

A

dura mater; epidural space

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12
Q

What are the 5 branches of the internal carotid artery?

A
Opthalmic
Posterior Communicating
Anterior Choroidal
Anterior Cerebral
Middle Cerebral
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13
Q

What other structure runs alongside the opthalmic artery through the optic foramen?

A

optic nerve

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14
Q

The Opthalmic artery supplies what structure?

A

retina

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15
Q

The Posterior Communicating Artery runs in which direction and joins what 2 arteries?

A

posterior;

posterior cerebral artery and internal carotid artery

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16
Q

The Posterior Communicating Artery forms part of what structure?

A

Circle of Willis

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17
Q

The Anterior Choroidal Artery supplies _____ structures, namely _____, ______, and _____.

A

deep;
basal ganglia
thalamus
internal capsule

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18
Q

What is the internal capsule?

A

Bunch of tightly packed axons descending from the cerebrum (part of the frontal lobe), running anterior ->posterior.

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19
Q

The Anterior Cerebral Artery travels in what structure of the brain?

A

sagittal fissure

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20
Q

The Anterior Communicating Artery joins what?

A

the Anterior Cerebral Arteries from each side

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21
Q

T/F: The Anterior Cerebral Artery runs over the thalamus.

A

False (runs over corpus callosum)

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22
Q

The Anterior Cerebral Artery travels in the _______ space and sends penetrating branches to cortex and ____ matter

A

sub-archnoid; white

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23
Q

The cortical (surface) branches of the Anterior Cerebral Artery supply which section of the cerebrum?

A

anterior-medial

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24
Q

T/F: The cortical branches of the Anterior Cerebral artery supply the primary somatosensory region. Does it supply all sections of the primary somatosensory regions?

A

True; mostly medial section

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25
Q

The Anterior Cerebral Artery supplies the motor and sensory cortical areas for the ____ limbs.

A

lower

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26
Q

How are deep structures of the brain supplied?

A

supplied by small penetrating branches from initial segments of main cerebral arteries

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27
Q

Deep branch of the Anterior Cerebral Artery supplies ____ and ____.

A

basal ganglia and internal capsule.

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28
Q

Which three arteries both supply the basal ganglia and the internal capsule?

A

Anterior Choroidal Artery
Anterior Cerebral Artery
Middle Cerebral Artery

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29
Q

What is the significance of the Recurrent

artery of Heubner?

A

Common area checked for plaque deposits impeding circulation.

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30
Q

What is the largest branch of the Internal Carotid Artery?

A

Middle Cerebral Artery

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31
Q

The Middle Cerebral Artery runs ____ in the ____ fissure.

A

laterally; Sylvian

32
Q

The cortical (surface) branches of the Middle Cerebral Artery supply mostly the ____ surface of the cerebral hemispheres.

A

lateral

33
Q

Infarct of the Middle Cerebral Artery, supplying the lateral part of the primary motor and sensory cortex, will show deficits mainly in which 2 parts of the body?

A

upper extremities and face

34
Q

Deep penetrating branches of the Middle Cerebral Artery supply which 2 structures?

A

basal ganglia & internal capsule

35
Q

What are lenticulostriate arteries and where are they located?

A

They’re the deep penetrating branches of the Middle Cerebral Artery and are located deep.

36
Q

What is a Cerebrovascular Accident (CVA)? What are the 2 main types of CVAs? Of the two which is most common?

A

A sudden death of brain tissue by a lack of oxygen and glucose delivery due to interrupted blood supply.
2 types: ischemic (most common) & hemorrhagic

37
Q

Which is more common: anterior circulation stroke or posterior circulation stroke?

A

anterior circulation stroke

38
Q

What are the 3 causes of ischemic stroke?

A
  1. Atherosclerotic plaque/thrombosis
  2. Thrombo-embolus
  3. Embolus
39
Q

Define: Thrombosis, Thrombo-embolus, and Embolus.

A

Thrombosis: blood clot (usually plaque)
Thrombo-embolus: blood clot that has traveled from artery to artery within the brain
Embolus: blood clot that traveled to the brain from a different location

40
Q

What is a hemorrhagic stroke? What are the 4 causes?

A

A rupture of weak vessel wall causing blood to leak into brain tissue around it.

  1. longstanding hypertension
  2. rupture of aneurysm
  3. arteriovenous malformation
  4. trauma to head
41
Q

What are the 2 categories of intracranial hemorrhage?

A

intracerebral hemorrhage

subarachnoid hemorrhage

42
Q

T/F: The Middle Cerebral Artery is a common site for hemorrhagic stroke.

A

False (ischemic)

43
Q

What kind of deficits would be typical of Middle Cerebral Artery large vessel infarcts (on surface of cerebrum)?

A

motor and sensory loss, especially affecting the face and upper limb; speech/language

44
Q

Why are lenticulostriate arteries prone to infarcts (2 reasons)?

A
  1. b/c prone to narrowing with hypertension

2. b/c prone to rupturing

45
Q

Trace the path of the posterior circulation from heart to just as it enters the cranium.

A

aorta -> subclavian artery -> vertebral artery

46
Q

Branches from the _____ artery supplies the spinal chord.

A

vertebral

47
Q

Describe the blood supply to the spinal chord.

A

There are paired posterior spinal arteries and one anterior spinal artery.

48
Q

Posterior Inferior Cerebellar Artery is a branch of what main artery?

A

Vertebral Artery

49
Q

The Posterior Inferior Cerebellar Artery supplies what 2 structures?

A
  1. Inferior surface of cerebellum

2. Medulla oblongata

50
Q

What is the lowest part of the brain?

A

medulla oblongata

51
Q

Which arteries join to form the Basilar Artery? Where on the brain does this occur?

A

vertebral arteries; lower border of the pons

52
Q

What are the 5 branches of the Basilar Artery?

A

(Hint: LAPPS)

  1. Lasbyrinthine artery
  2. Anterior inferior cerebellar artery
  3. Pontine arteries
  4. Posterior CEREBRAL artery
  5. superior cerebellar artery
53
Q

Are the Anterior Inferior Cerebellar arteries and the Posterior Inferior Cerebellar arteries supplied by the same main artery?

A

No
Anterior Inferior Cerebellar arteries (Basilar Artery)
Posterior Inferior Cerebellar arteries (Vertebral artery)

54
Q

Posterior Cerebral Arteries: the cortical branches supply which 2 lobes of the brain?

A

occipital and temporal

55
Q

The damage of which 2 arteries could lead to vision damage?

A

Opthalmic arteries and Posterior Cerebral arteries

56
Q

The deep branches of the Posterior Cerebral Arteries supply which 3 structures?

A

thalamus, midbrain, posterior part of internal capsule

57
Q

Define the Circle of Willis.

A

A “circle‟ of anastomoses of anterior and posterior circulations

58
Q

Since all major cerebral vessels communicate via the Circle of Willis it serves as what?

A

a back up for cerebral circulation b/c of collateral circulation

59
Q

List the 7 arteries included in the Circle of Willis.

A
Anterior cerebral arteries
Anterior communicating artery
Middle cerebral artery
Internal carotid artery
Posterior communicating artery
Posterior cerebral artery
Basilar artery
60
Q

What are Watershed zones an why are they clinically important?

A

They are regions between cerebral arteries that are highly susceptible to ischemia and infarctions.

61
Q

Do Watershed zones get the most amount of circulation?

A

No: they are on the borders of the 2 arteries so they usually receive the least amount of blood flow

62
Q

What would the Watershed zone between the Anterior Cerebral Artery and the Middle Cerebral Artery be called?

A

ACA - MCA watershed

63
Q

Nearly all venous drainage of brain is via _____ _____ vein.

A

Internal Jugular

64
Q

How does the internal jugular vein exit the skull?

A

Jugular foramen

65
Q

Superficial veins of the cerebral hemisphere drain mainly into which 2 sinuses?

A
  1. superior sagittal sinus

2. cavernous sinus

66
Q

Deep veins of the cerebral hemisphere drain into what?

A

great vein of Galen

67
Q

Trace the venous drainage pathway from the superior sagittal sinus.

A

Superior Sagittal sinus -> Transverse Sinus -> Sigmoid Sinus -> Internal Jugular Vein

68
Q

Trace the venous drainage pathway from the cavernous sinus.

A

a) Cavernous sinus ->superior petrosal sinus ->Transverse sinus -> Sigmoid sinus -> Internal jugular vein
b) Cavernous sinus -> Inferior Petrosal Sinus -> Internal Jugular vein

69
Q

Trace the venous drainage pathway from the great vein of Galen.

A

great vein of Galen -> inferior sagittal sinus ->straight sinus -> transverse sinus -> internal jugular vein

70
Q

Define the Blood Brain Barrier (BBB).

A

The blood–brain barrier (BBB) is a separation of circulating blood from the brain extracellular fluid in the central nervous system (CNS).

71
Q

List the 4 ways in which the BBB maintains an optimum environment for CNS function.

A
  1. maintains brain electrolyte levels
  2. modulates entry of various substrates into the CNS (e.g. glucose levels)
  3. removes waste products
  4. excludes toxins
72
Q

What are the 2 main features of a brain capillary (as opposed to a systemic capillary) which forms the BBB?

A

tight junctions between endothelial cells; astrocytes

73
Q

Where is the choroid plexus located? Describe how the barrier forms between the blood and the CSF in the choroid plexus.

A

ventricles;
capillaries in the choroid plexus are permeable but there’s a layer of choroid epithelial cells that separate the capillaries from the ventricles. These epithelial cells have tight junctions which prevent the blood from mixing with the CSF.

74
Q

Separate the following into those that would cross and wouldn’t cross the BBB:

  • O2
  • alcohol
  • potassium
  • lipid insoluble molecules
  • lipid soluble molecules
  • lipid soluble drugs
  • large molecules
A

Would cross BBB: o2, CO2, lipid soluble drugs, alcohol

Would not cross BBB: potassium, lipid insoluble molecules, large molecules

75
Q

The Blood Brain Barrier could break down due to what 4 things? If the BBB does break down, it could cause what 2 disorders?

A

infection, brain tumour, trauma, stroke;

encephalitis, excessive fluid (edema) in interstitial space