Blood supply

Question 1

What major area does the internal carotid a. supply?

Answer 1

Most of cerebrum

Question 2

What does the ICA bifurcate into?

Answer 2

Anterior and middle cerebral aa. (ACA, MCA)

Question 3

What are the major branches of the ICA (ACA + MCA)?

Answer 3

• Ophthalmic a.
• Anterior choroidal a.
• Posterior communicating a. (PCoA)

Question 4

What major area does the vertebrobasilar a. supply?

Answer 4

Brainstem, cerebellum, sc

Question 5

What do the vertebral aa. fuse to form?

Answer 5

Basilar a.

Question 6

What are the major vertebral branches of the vertebrobasilar a?

Answer 6

• Posterior inferior cerebellar a. (PICA)
• Posterior spinal aa.
• Anterior spinal a.

Question 7

What are the major basilar branches of the vertebrobasilar a?

Answer 7

Basilar:

• Anterior inferior cerebellar a. (AICA)
• Superior cerebellar a. (SCA)

Question 8

What does the basilar a. bifurcate into?

Answer 8

2 Posterior cerebral aa. (PCA)

Question 9

What are the roots of the anterior, middle, and posterior cerebral aa.?

Answer 9

ACA: ICA
MCA: ICA
PCA: Basilar a.

Question 10

Generally, what does circle of Willis interconnect?

Specifically?

Answer 10

• Anterior and posterior cerebral circulations

- Connects ACA to each other (via ACoA), MCA to PCA (via PCoA)

Question 11

What types of aa. supply deep cerebral structures?

Answer 11

Small perforating (ganglionic) aa. at base of brain

Question 12

What supplies the deep structures of the diencephalon, hypothalamus, and telencephalon?

Answer 12

MCA branches known as lenticulostriate aa.

AKA anterolateral central aa.

Question 13

What is the name for the area w/entry points of the small perforating (ganglionic) aa?

Answer 13

Anterior and posterior perforated substance

Question 14

What are the layers of the BBB?

Answer 14

1. Endothelial cells w/tight junctions (large role)
   1a. Endothelial basal lamina (proteins, carbs, lipids, etc.)
2. Pericytes (large role)
3. Pia mater (in larger vessels only)
   3a. Another Basal lamina
4. Astrocyte end-feet (likely smaller role)
5. Neuronal processes (interact w/astrocytes and pericytes)

Question 15

What are some roles of pericytes in the BBB?

Answer 15

• Form tight junctions of endothelial cells and regulate their vesicular trafficking
• Protect from immune response
• Can contract to allow different size cells through the vessels
  (- They are likely crucial for post-natal formation of BBB)

Question 16

Do cerebral vv. have valves?

Do they have anastomoses?

Answer 16

• No

- Yes, numerous

Question 17

What is the fcn of emissary vv?

What’s a clinical implication of them?

Answer 17

Connect extracranial vv. w/dural venous sinuses

- Infection can spread from face/scalp into brain thru them

Question 18

What are the 2 major divisions of the cerebral venous system?

Answer 18

Superficial + deep veins

Question 19

Where does the superior group of superficial vv drain?

Answer 19

Superior and inferior sagittal sinuses

Question 20

Where does the inferior group of superficial vv drain?

Answer 20

Transverse and cavernous sinuses

Question 21

Where do vv. of the cerebellum and brainstem drain?

Answer 21

Deep sinus (great v. of Galen), straight sinus, transverse sinus, and petrosal sinus

Question 22

Brain takes up __% of body weight, __%; CO, and __% O2 consumption

Answer 22

2, 15, 25

Question 23

Normally, the brain uses __mL of blood/100g CNS/minute
At what level do neurons stop generating signals?
At what level does brain tissue necrosis begin to occur?

Answer 23

55
20mL
10mL

Question 24

What cells control “autoregulation” of blood flow?

Answer 24

Arteriole and smooth m. cells

Question 25

Explain the process of metabolic control of blood flow.

Answer 25

Increased neuronal activity → glutamate released → astrocyte end feet receptors activated → vasodilator factors released at end-feet applied to vessels

Question 26

What are some of the main fcns of the BBB?

Answer 26

• Restrict ion/fluid movement
• Supplies essential nutrients
• Mediates efflux of waste or toxic products

Question 27

What color are bones on CT? What about hemorrhages?

Answer 27

White, white

Question 28

What are some drawbacks of MRI?

Answer 28

• Can’t do it w/metal (pacemakers…)
• Some people are claustrophobic
• Takes longer than CT (CT is for emergencies)

Question 29

What is the source of bleeding for an epidural hematoma?

Answer 29

Middle meningeal a.

Question 30

Define herniation syndrome, generally. Would it be more likely to occur in young or old people during a hemorrhage?

Answer 30

Parts of the brain expand so much that they push on other structures/brain stem
- Young, people their brain takes up more space in the cranial vault (old people already have atrophy)

Question 31

Define Virchow-Robin space (perivascular space).

Answer 31

When bv’s come into neural tissue from the SAS they take some of the pia mater with them, and the space b/w the pia mater and the bv is called perivascular space.

Question 32

What group of aa. comes off the basilar b/w AICA and SCA?

Answer 32

Pontine aa.

Question 33

What a. comes off the ICA before it becomes the MCA and ACA?

Answer 33

Ophthalmic a.

Question 34

What main a. comes off the middle cerebral a?

Answer 34

Anterior choroidal a.