S1_L4: Blood Supply of the Brain

Question 1

What are the four arteries supplying the brain?

Answer 1

Two internal carotid arteries
Two vertebral arteries

Question 2

TRUE OR FALSE: The normal cerebral blood flow is 50-60 ml/100 g of brain tissue per minute

Answer 2

True

Source: BRS Neuroanatomy, 6th; Snell’s Clinical Neuroanatomy, 8th

Question 3

The internal carotid arteries account for what percentage of cerebral circulation?

Answer 3

80%

Question 4

The vertebral arteries account for what percentage of cerebral circulation?

Answer 4

20%

Question 5

The basilar artery is formed by the union of ___

Answer 5

Two vertebral arteries

Question 6

The posterior cerebral artery is not branch of internal carotid artery. The posterior communicating artery is a branch of internal carotid artery.

A. First statement is correct
B. Second statement is correct
C. Both are correct
D. Both are incorrect

Answer 6

C. Both are correct

Question 7

Where is the Circle of Willis located?

Answer 7

In the interpeduncular fossa at the base of the brain

Question 8

Enumerate the 3 small arteries of the spinal cord

Answer 8

Posterior spinal arteries (2)
Anterior spinal artery (1)

Question 9

An increase in (1)___ or (2)___ ion concentration in the cerebral circulation has the most powerful vasodilator influence on cerebral blood vessels.

Answer 9

1. Carbon dioxide
2. Hydrogen

Note: Reduction in oxygen concentration also causes vasodilation

Question 10

What is the most important factor in forcing the blood through the brain?

Answer 10

Arterial blood pressure

Question 11

What are the 3 factors that oppose the arterial blood pressure?

Answer 11

1. Raised intracranial pressure
2. Increased blood viscosity
3. Narrowing of the vascular diameter

Question 12

TRUE OR FALSE: Cerebral blood flow remains constant despite changes in general BP

Answer 12

True

Question 13

What is the largest branch of the internal carotid artery?

Answer 13

Middle cerebral artery

Question 14

What is formed by the tight junctions that exist between the endothelial cells in the capillary beds and serves to isolate the brain tissue from the rest of the body?

Answer 14

Blood—brain barrier

Question 15

TRUE OR FALSE: Capillary blood supply to the brain is greater in the gray matter than in the white matter.

Answer 15

True

Reason: Because metabolic activity in the neuronal cell bodies in the gray matter is much greater than in the nerve processes in the white matter

Question 16

Cerebral blood vessels are innervated by ____ nerve fibers and respond to norepinephrine.

Answer 16

Sympathetic postganglionic

Question 17

TRUE OR FALSE: Autoregulation of the circulation is accomplished by compensatory lowering of the cerebral vascular resistance when the arterial pressure is decreased. The cerebral vascular resistance rises when arterial pressure is increased.

Answer 17

True

Question 18

What is considered as the main factor contributing to cerebrovascular resistance?

Answer 18

The diameter of cerebral blood vessels

Question 19

Determine the corresponding supply to specific areas of the brain

1. Branches of the posterior communicating, basilar, and posterior cerebral arteries
2. Posterior cerebral, superior cerebellar, and basilar arteries
3. Vertebral, anterior and posterior spinal, posterior inferior cerebellar, and basilar arteries
4. Superior cerebellar, anterior inferior cerebellar, and posterior inferior cerebellar arteries
5. Basilar, and the anterior inferior and superior cerebellar arteries

A. Medulla oblongata
B. Pons
C. Midbrain
D. Cerebellum
E. Thalamus

Answer 19

1. E
2. C
3. A
4. D
5. B

Question 20

Determine the corresponding descriptions of the external cerebral veins

1. Drains the insula and is joined by the anterior cerebral and striate veins to form the basal vein
2. Empty into the superior sagittal sinus
3. Drains the lateral surface of the cerebral hemisphere
4. Empty into the cavernous sinus

A. Superior cerebral veins
B. Superficial middle cerebral vein
C. Deep middle cerebral vein

Answer 20

1. C
2. A
3. B
4. B

Question 21

Determine the corresponding descriptions of the branches of the basilar artery

1. Gives rise to the labyrinthine artery, and supplies the hypothalamospinal tract, anterior and inferior parts of cerebellum
2. Numerous small vessels that enter the substance of the pons, supply corticospinal tracts and intra-axial exciting fibers of CN VI
3. Provides the major blood supply to the midbrain
4. Long, narrow artery that accompanies CN VII and CN VIII into the internal acoustic meatus and supplies the internal ear
5. Supplies the superior surface of the cerebellum

A. Anterior inferior cerebellar artery
B. Superior cerebellar artery
C. Posterior cerebral artery
D. Pontine artery
E. Labyrinthine artery

Answer 21

1. A
2. D
3. C
4. E
5. B

Question 22

Determine the corresponding descriptions of some branches of the basilar artery

1. Supplies the rostral and lateral pons, pineal gland, & superior medullary velum
2. Its choroidal branch supplies the choroid plexus
3. Supplies the visual cortex
4. Few of its branches pass to the pons and upper part of the medulla oblongata
5. Its central branches supply posterior half of the thalamus, lentiform nucleus, midbrain, pineal, and medial & lateral geniculate bodies

A. Anterior inferior cerebellar artery
B. Superior cerebellar artery
C. Posterior cerebral artery

Answer 22

1. B
2. C
3. C
4. A
5. C

Question 23

Determine the corresponding descriptions of some branches of the cerebral portion

1. Supplies the eye and other orbital structures
2. Small branches supply the crus cerebri, lateral geniculate body, optic tract, and internal capsule
3. Enters the orbit through the optic canal below and lateral to the optic nerve
4. It passes posteriorly close to the optic tract, enters the inferior horn of lateral ventricle, and ends in choroid plexus
5. Runs posteriorly above the oculomotor nerve to join the posterior cerebral artery, forming part of the circle of Willis

A. Ophthalmic artery
B. Posterior communicating artery
C. Choroidal artery

Answer 23

1. A
2. C
3. A
4. C
5. B

Question 24

Determine the corresponding descriptions of the anterior and middle cerebral arteries

1. Cortical branches supply all the medial surface of the cerebral cortex
2. Runs laterally in the lateral cerebral sulcus
3. Supplies the “leg area” of the precentral gyrus
4. Supplies all the motor area except the “leg area”
5. Runs forward and medially superior to the optic nerve and enters the longitudinal fissure of the cerebrum

A. Anterior cerebral artery
B. Middle cerebral artery

Answer 24

1. A
2. B
3. A
4. B
5. A

Question 25

Determine the corresponding descriptions of some branches of the cranial portion 1. Supplies the inferior surface of the vermis, the central nuclei of the cerebellum, and the undersurface of the cerebellar hemisphere 2. May give rise to the posterior spinal artery 3. Supply the bone and dura in the posterior cranial fossa 4. Largest branch of the vertebral artery 5. Very small branches that are distributed to the medulla oblongata A. Posterior inferior cerebellar artery B. Medullary arteries C. Meningeal branches

Answer 25

1. A 2. A 3. C 4. A 5. B

Question 26

Determine the corresponding descriptions of the anterior and posterior spinal arteries 1. Supply the anterior and lateral horns and anterior and lateral funiculi 2. Arise directly from the vertebral artery or indirectly from the posterior inferior cerebellar arteries 3. Supply the gracile and cuneate fasciculi and nuclei in the medulla 4. Very small in the upper and lower thoracic segments of the spinal cord 5. Embedded in the pia mater along the anterior median fissure A. Anterior spinal artery B. Posterior spinal artery

Answer 26

1. A 2. B 3. B 4. A 5. A

Question 27

Determine the corresponding venous drainage of specific areas of the brain 1. Veins that empty into the great cerebral vein (vein of Galen) or adjacent venous sinuses 2. Veins that open into the basal of great cerebral veins 3. Veins that open into the spinal veins and neighboring venous sinuses 4. Veins that open into the basal vein, cerebellar veins, or neighboring venous sinuses A. Medulla oblongata B. Pons C. Midbrain D. Cerebellum

Answer 27

1. D 2. C 3. A 4. B

Question 28

What does an intracarotid injection or inhalation of radioactive krypton or xenon measure?

Answer 28

Cerebral blood flow

Question 29

The four arteries of the brain lie within the cerebrospinal fluid of the subarachnoid space, and their branches anastomose on the inferior surface of the brain to form ____

Answer 29

Circle of Willis

Question 30

The venous drainage of the ___ is the pathway for transmission of infectious agents and tumor cells

Answer 30

Spinal cord Additional: Blood passes from spinal veins within the subarachnoid space to the epidural internal venous plexus before draining into intracranial, cervical, thoracic, intercostal, or abdominal veins Source: BRS Neuroanatomy, 6th

Question 31

The internal carotid artery begins at the bifurcation of the (1)____ in the neck, where it usually possesses a localized dilatation, the (2)____

Answer 31

1. Common carotid artery 2. Carotid sinus

Question 32

What are the 6 arteries that are part of the Circle of Willis?

Answer 32

1. Internal carotid 2. Anterior communicating 3. Anterior cerebral 4. Posterior communicating 5. Posterior cerebral 6. Basilar

Question 33

TRUE OR FALSE: The veins of the brain have no muscular tissue in their very thin walls, and they possess no valves.

Answer 33

True

Question 34

This artery may be the major source of blood to the lower two-thirds of the spinal cord

Answer 34

Great Anterior Medullary Artery of Adamkiewicz

Question 35

The Great Anterior Medullary Artery of Adamkiewicz is a large and important feeder artery. It arises from the aorta in the lower thoracic or upper lumbar vertebral levels, origin varies from (1)____. It is usually (2)____, arising on the left side.

Answer 35

1. T12 to L4 2. Unilateral Source: BRS Neuroanatomy, 6th

Question 36

These provide the main blood supply to the spinal cord at thoracic and lumbar levels where spinal arteries become inconsistent.

Answer 36

Segmental spinal arteries Source: BRS Neuroanatomy, 6th

Question 37

Which lumbar artery gives rise to the large anterior medullary artery, the artery of Adamkiewicz?

Answer 37

Second lumbar artery Source: BRS Neuroanatomy, 6th

Question 38

The arteries of the brain provide the brain with (1)___% of the oxygen used by the body. (2)___% of the cardiac output goes to the brain.

Answer 38

1. 20 2. 15

Question 39

Sympathetic stimulation of the sympathetic postganglionic nerve fibers supplying the cerebral arteries causes _____ of the cerebral arteries

Answer 39

Vasoconstriction

Question 40

The sympathetic and postganglionic nerve fibers are the nerve supply of the cerebral arteries. These fibers are derived from the ___ sympathetic ganglion.

Answer 40

Superior cervical

Question 41

TRUE OR FALSE: When an artery on one side is occluded, the arterial circle permits blood to flow across the midline.

Answer 41

True

Question 42

The vertebral artery is a paired branch of the first part of the (1)___. It ascends the neck by passing through the foramina in the transverse processes of the (2)___ cervical vertebrae

Answer 42

1. Subclavian artery 2. Upper six / C1-C6

Question 43

At the junction between the medulla and the pons (lower border), the two vertebral arteries fuse to form the ____ on the anterior surface of the pons.

Answer 43

Basilar artery Source: BRS Neuroanatomy, 6th

Question 44

At the upper border of the pons, the basilar artery divides into the two ____ arteries.

Answer 44

Posterior cerebral

Question 45

The internal cerebral veins are formed by the union of what 2 veins where they run posteriorly in the tela choroidea of the third ventricle?

Answer 45

Thalamostriate and choroid veins

Question 46

The corpus striatum and the internal capsule are supplied mainly by the medial and lateral striate central branches of the ____ artery

Answer 46

Middle cerebral Additional: The central branches of the anterior cerebral artery supply the remainder of these structures