Cns Blood Supply

Front 1

1. What are the 2 pairs of a. that supply the brain (foramen they enter through)?

CNS is a Me 1st sys. it will get what it needs despite alteration in systemic BP... There is transient increases in bloodflow in areas of the brain that are more active

Back 1

1. Internal carotid (carotid canal) and the vertebral (foramen magnum)

Front 2

CNS does not store O2 or glucose
1. What percent of O2 and cardiac output does the CNS use?
2. Why do neurons have a high metabolic rate?

Back 2

1. 20% and 17%
2. energy required to pump large quantities of ions across their membranes

Front 3

1. Where is the metabolic rate higher, gray or white matter?
2. What is the initial cause of damage from ischemia?
3. How long does it take brain ischemia to lead to unconsciousness?

Back 3

1. Gray matter, so has more capillaries
2. Anoxia
3. 10 seconds, few minutes for necrosis

Front 4

Three mechanism regulate blood flow, name them:
1. cerebral blood vessels dynamically alter their diameter in order to maintain the metabolically required blood flow despite changes in systemic blood pressure. This mechanism is poorly understood, and may be due to vascular stretch receptors
2. cerebral blood vessels dilate in response to increased levels of CO2 or H+ (and decrease in O2 levels) in brain extracellular fluid.

Back 4

1. Autoregulation
2. Response to metabolites

third is Autonomic inervation of cerebral arteries

Front 5

Three mechanism regulate blood flow, name them:
1. sympathetic innervation from cervical ganglia. Little influence except when arterial pressure becomes extremely high; constricts larger cerebral arteries which can prevent hemorrhage from smaller diameter arteries.

Back 5

1. Autonomic innervation of cerebral arteries

Front 6

1. What is formed by: – endothelial cells that line the
continuous capillaries of the CNS have tight junctions between them which prevent the passage of macromolecules. These tight junctions are reinforced externally by the end feet of astrocytes

Back 6

1. Blood brain barrier

Front 7

1. How do substances get across the BBB?
2. Most common cause of BBB breakdown?

Back 7

1. via active transport. Molecules with a high electronic charge are slowed, but highly lipid soluble drugs pass through well (barbituate drugs)
2. HTN

Front 8

1. What incoming a. provides the circulation of the anterior 2/3 of the brain (2 main subdivisions)?
2. a. that passes through the Sylvian (lateral) fissure and distributes branches to the lateral portions of the cortex and subcortex (lateral 2/3 of anterior 2/3)
3. a. distributes branches to the medial portion of the cortex and subcortex (Middle 1/3 of anterior 2/3)

Back 8

1. Internal carotid (Anterior and middle cerebral a.)
2. Middle cerebral a.
3. Anterior cerebral a.

Front 9

1. What lobes make up the cortex of the brain?
2. What are the 2 main subcortical branches of the middle cerebral a. (what do they supply)?

Back 9

1. Frontal, parietal and temporal lobes as well as the
insular cortex
2. Anterior choroidal (choroid plexus, amygdala, hippocampus, part of internal capsule, and optic tract)
Lateral striate [Lenticulostriate] (internal capsule mostly and the basal ganglia (caudate nucleus and putamen))

Front 10

1. What a. is damaged if fxn is lost to primary motor/sensory cortex to face, UE's & trunk, the language areas, association areas, and sensory association areas

Back 10

1. Middle cerebral a. - most commonly involved in CVA

Front 11

1. What 2 a. branch from the anterior cerebral a. in the cortical territory? (supply what?)
2. What fissure does the anterior cerebral a. pass through?
3. What a. does the anterior cerebral a. branch off subcortically?

Back 11

1. Pericallosal (medial surface of parietal lobe) & Callosomarginal a. (medial part of the pre and post central gyri, and parts of the cingulate gyrus
2. Median longitudinal suture
3. Medial striate a. supplies the head of caudate nucleus, part of internal capsule

Front 12

1. What a. is damaged if primary motor/sensory to LE is lost, lose corpus callosum, and limbic system?
2. What provides the circulation to the posterior 1/3 of the brain, the cerebellum, and the entire brain stem

Back 12

1. Anterior cerebral a.
2. Vertebral-basilar system

Front 13

1. What are the 3 major branches of the vertebral a? (supplies what)

Back 13

1. Posterior inferior cerebellar arteries PICA (infeior surface of the cerebellum, inferior cerebellar peduncle, some 4th ventricle choroid plexus, lateral portion of upper medulla)
2. Posterior spinal arteries (dorsal portion of caudal medulla, dorsal horn and dorsal columns of the spinal cord
3. Anterior spinal a. (medial and ventral portions of the medulla (pyramids, medial longitudinal fasciulus, motor nuclei, etc) anterior and lateral spinal horns, base of dorsal horn, central gray matter of spinal cord

Front 14

1. What a. supplies the anterior 2/3 of the spinal cord? (posterior 1/3)
2. What is the classic presentation of the CN III?
3. What a. do the vertebral a. merge to form?

Back 14

1. Anterior spinal a. (posterior spinal a.)
2. between the posterior cerebral a. and the superior cerebellar a.
3. Basilar a.

Front 15

What are the 4 major branches of the basilar a. and what do they supply?

Back 15

1. Anterior inferior cerebellar a. - lateral region of caudal pons and portions of the inferior surface of the cerebellum
2. Labryinthine a. - supplies inner ear, enters through the acoustic meatus
3. Pontine a. - anterior and lateral regions of pons
4. Superior cerebellar a. - rostral portions of pons, the midbrain, superior surface of cerebellum

Front 16

1. What does the basilar a. bifurcate into rostrally?

Back 16

1. Into posterior cerebral a. - supplies the lateral aspect of the midbrain, thalamus and medial inferior portion s of the temporal lobe and all of the occipital lobe (visual cortex)

Front 17

1. What is the main fxn of the circle of Willis?
2. What is the blood supply to the pons?

Back 17

1. Equalize blood flow to various parts of the brain and allow rapid changes in flow depending on regional metabolic needs
2. Pontine branches of the basilar a.

Front 18

1. What is the blood supply to the Medulla?

Back 18

1. Anterior spinal a. supplies the medial part (disruption injures motor tracts), Posterior inferior cerebellar a. supplies the dorsolateral part of the medulla (sensory tracts) and the vertebral a. supplies an area between the other 2

Front 19

1. What is the blood supply to the midbrain?

Back 19

1. Posterior cerebellar a. supplies the dorsolateral region rostrally
Superior cerebellar a. supplies dorsolateral region caudally
Pontine branches of the basilar a. supply ventral and part of dorsal regions

Front 20

1. What 2 main a. supply the spinal cord?
2. What are these supplemented by below the cervical region?

Back 20

1. Anterior spinal and posterior spinal a.
2. Radicular a., spinal branches of segmental a., a. of Adamkiewicz (great anterior segmental a.)

Front 21

1. What 2 systems allow venous return of blood from the brain
2. What v. group lies in thee SAS, drains superfcial cortex and empties into superior sagittal sinus?

Back 21

1. Deep and superficial cerebral veins & venous sinuses (within dura mater) so occlusio of any 1 channel is no problem
2. Superficial cerebral veins (in vorder of falx cerebri)

Front 22

1. What v. group carries blood away from internal structures (basal ganglia, thalamus etc)
2. Subgroup of 1 that lie on the dorsomedial aspect of the thalamus and drain the internal regions of the hemisphere dorsal and lateral to the caudate nucleus
3. Subgroup of 1 that run from the frontal lobe along the medial aspect of the temporal lobe draining the ventromedial portion of the hemispheres

Back 22

1. Deep cerebral v.
2. Internal cerebral v
3. Basal v. of Rosenthal

Front 23

1. What doe the internal cerebral v. and basal v. of Rosenthal join to form?
2. Sinus situated bilaterally on each side of sella turcica, thin walled, no valves, blood from orbit, pituitary, hypothalamus, paranasal sinus
3. Where does 2 drain to?

Back 23

1. Great cerebral v. of Galen which drains into the straight sinus
2. Cavernous sinus
3. Sigmoid sinus via petrosal sinus

Front 24

1. What CN are in the cavernous sinus? what main a.?
2. term for the meeting place of the superior sagittal, straight, occipital, and transverse sinuses
3. Path of blood from 2 to the internal jugular?

Back 24

1. CN III, IV, V1, V2, and VI;;; Internal carotid a.
2. Conflucence of sinuses
3. Transverese sinuses, which becomes the sigmoid sinus, blood exits via the internal jugular v.

Front 25

1. What are the 2 types of CVA?
2. term for vesel rupture, bleeds into SAS
3. Bleeds into brain tissue

Back 25

1. Hemorrhagic stroke & Ischemic stroke (blockage due to thrombus or embolus
2. Intracranial aneurysm
3. Intraparenchymal hemorrhage

Front 26

1. Term for connections between a. and v. do not develop normally, a. connect directly to v. instead of through capillaries, vessels tend to enlarge and eventually rupture

Back 26

1. Ateriovenous (AV) malformation, rare 2% of all CVAs