Ns Lab 3

Front 1

What is ischemia?

Back 1

CBQ <30-35 mg/100gm/min --- local anemia d/t lack of blood flow

Front 2

Infarction?

Back 2

If CBQ < 20 ml/100gm/min. Complete lack of blood supply to an area w/ irreversible damage occuring.

Front 3

How often is the blood in the brain turned over?

Back 3

5-7 times /min

Front 4

What causes 85% of strokes? The other 15%?

Back 4

85% d/t blockage from atherosclerosis or migrating clots.

15% d/t high BP &/or aneurysms

Front 5

What are the 2 groups of arteries that supply the brain? What are they branches of? Where do they come in?

Back 5

Internal carotid arteries - terminal branches of common carotid. carotid canal in the petrous temporal bone.

Vertebral arteries - branches of subclavian. pass through the foramina in the cervical vertebrae and the foramen magnum

Front 6

What are the 4 collateral branches of the internal carotid a?

Back 6

1. Hypophyseal
2. Opthalmic
3. Posterior communicating = connecting link bxt carotid & vertebral sys in Circle of Willis
4. Anterior choroidal a = supplies choroid plexus

Front 7

What are the terminal branches of the internal carotid a?

Back 7

1. Middle cerebral a
2. Anterior cerebral a

Front 8

What arteries supply the supratentorial structures?

Back 8

Internal carotid arteries -- Ant & Mid cerebral as

Vertebral arteries - Posterior cerebral as

Front 9

What arteries supply the infratentorial structures / posterior fossa?

Back 9

Vertebral arteries -- PICA, Basilar (ant inf cerebellar as, pontine, suerior cerebellar as)

Front 10

Where does the middle cerebral a come from?

Cortical branches?
Central branches?

Back 10

Internal carotids

Cortical branches -- lateral from origin to lateral fissure -- supply lateral surface

Central branches = lateral striate/lenticulostriate arteries. Lots of them -- Enter brain through anterior perforated substance. Supply deep structures like c. striatum & internal capsule.

Front 11

Clinical importance of middle cerebral artery?

Back 11

Carries 80% of blood to cerebral hemispheres -- MOST STROKES are related to this --> contralateral paralysis & sensory deficits in head arm and upper boddy. If damaged in L hemisphere --> speech & understanding problems.

Front 12

Where does the anterior cerebral a come from? What other structure is directly related to it?

Back 12

Terminal branch of internal carotid.
Anterior communicating artery joins them across the midline.

Front 13

What do the cortical branches of the Ant Cerebral as supply?

Back 13

Lower surface of frontal lobe / Olfactory bulb & tract / Medial surface of fro / par lobes / C. callosum

Front 14

Clinical significance of Ant Cerebral a?

Back 14

Paralysis & sensory loss in the contralateral lower extremity -- if pre and post central gyri of paracentral lobule are affected.

Front 15

What do the vertebral arteries do?

Back 15

Supply brain stem & cerebellum in posterior fossa and

diencephalon & other areas of cerebral cortex in supratentorial (like visual cortex in occipital lobe)

Front 16

What are imp branches of the vertebral arteries?

Back 16

1 - Spinal a. anterior spinal & posterior spinal

2 - PICA: posterior inferior cerebellar artery

Front 17

What other details about PICA are good to know?

Back 17

Largest branch from each vertebral artery

Prone to occlusion --> lateral medullary / PICA syndrome

Front 18

What forms the basilar artery? What are its branches?

Back 18

Basilar is where the 2 vertebral arteries come together.

Branches:
a. anterior inferior cerebellar
b. internal auditory (labyrinthine)
c. pontine
d. superior cerebellar

Front 19

What are the terminal branches of the basilar a ?

Back 19

Posterior cerebral -- basilar splits at the rostral border of the pons.

Front 20

What produces CSF?

Back 20

Choroid plexus.

Front 21

What is important about the calcarine branches of the post cerebral a?

Back 21

Supply visual cortex at occipital pole and along calcarine fissure!!

Occlusion -->blindness in contralateral visual field. (Contralateral homonymous hemianopsia)

Front 22

What are 3 things to know about Circle of Bruce Willis?

Back 22

1. Union of major cerebral arteries at base of brain
2. Frequent congenital variations here
3.Close lots of important brain structures -- pituitary, cranial nerves, cavernous sinus, optic nerve-chiasm & tract

Front 23

Differences bxt cortical/circumferential & central/ganglionic/perforating ?

Back 23

Cortical (circumferential) branches travel over the outside surface of the brain - penetrating into the brain from that outside surface. Originate in 'Bruce'

Central (ganglionic or perforating) branches penetrate into the ventral aspect of the brain directly from the arterial circle. The areas on the ventral surface of the brain where they enter is referred to as the “perforated substance”.
Also originates in 'Bruce'

Front 24

What should we know about the superficial cerebral veins?

Back 24

a. Located in subarachnoid space
b. Travel over and in the fissures/sulci of the cerebral hemisphere
c. Empty into nearest sinus

Front 25

What is the venous drainage of the deep cerebral venous system?

Back 25

Looking at the flowchart is way easier than writing it out. Pg 7 of handout / slide 27 of ppt.

Front 26

What is a thrombus?

Back 26

Clot that forms in place where it blocks blood

Front 27

Embolus?

Back 27

Clot that forms in one location and travels to the brain where it blocks blood flow.

Front 28

CVA

Back 28

Cardiovascular accident

Front 29

Occlusion

Back 29

blockage of blood fow --> ischemia --> infarction or necrosis

85% of stroke events are occlusive!!

Front 30

Intracranial v extracranial occlusions

Back 30

Intracranial -- usually embolic (MCA)

Extracranial -- Usually thrombotic ex: junction of internal carotid

Front 31

Hemorrhage

Back 31

Rupture of blood vessels / bleeding into and or around brain

Intracranial - in brain
Aneurysm - ballooning of blood vessel, often near Circle of Bruce Willis - bleed into subarachnoid area when rupture - mostly congenital