Blood Supply, Hemorrhages, Ischemic Stroke

Question 1

1. 2 main arteries that supply cerebral hemispheres (broad)
2. Main arteries supplying the cerebral hemispheres (branches of following answer)
   ~check notes for picture and look at pictures in the ppt for most of this info

Answer 1

1. ICA and vertebral arteries

2. Anterior, middle and posterior cerebral arteries

Question 2

1. Blood from anterior and middle cranial fossa drain thru dural venous sinuses to get reach __ which drains into __
2. Posterior cranial cavity reaches __ which drains into ___

Answer 2

1. Transverse sinuses; IJVs

2. Sigmoid sinus; jugular foramen

Question 3

1. Blood drains from brain by series of superficial cerebral veins - these are surrounded by
2. They empty into?

Answer 3

1. Pia mater

2. Dural venous sinuses directly or via bridging veins

Question 4

Deep veins:
Ultimately empty into __ via __

*look at pic in ppt for deep veins

Answer 4

Straight sinus via great cerebral vein (great vein of galen)

Question 5

1. 3 major veins that go into cavernous sinus

2. 2 sinuses for drainage of cavernous sinus

Answer 5

1. Cerebral veins, regional dural venous sinuses, and ophthalmic veins
2. Superior and inferior petrosal sinuses

Question 6

Cavernous sinus thrombosis

1. Affects what CNs?
2. Common cause?

Answer 6

1. III, IV, V1, V2, and IV (all located in cavernous sinus)

2. Facial infection (facial vein)

Question 7

Difference between ischemia and infarct?

Answer 7

Ischemia is inadequate blood flow; infarct is when ischemia is enough for damage to be permanent

Question 8

Cerebral blood flow:
1. Ischemia is below __ ml of blood / __ g brain per minute

2. Ischemia is below __ mmHg cerebral perfusion pressure

Answer 8

1. 50ml/100g

2. 40 mmHg

Question 9

Hypoxia-ischemia patterns for strokes:

1. Local
2. Global
3. Hypoxic

Answer 9

1. Thromboembolic- less perfusion of affected artery
2. Drop in cerebral perfusion pressure below 40 mmHg
3. Normal to increased cerebral blood flow, damage to vulnerable neurons

Question 10

Thrombus vs embolus? Which is more serious

Answer 10

Thrombus= blood clot
Embolus= piece of blood clot breaks off and becomes stuck in blood vessel (more serious)

Question 11

Why are lacunar infarcts not super serious?

Answer 11

They are infarcts that happen in small vessels

Question 12

Global: 2 ways for it to occur

1. Drop in systemic BP: could be from what 3 types of shock
2. Increase in intracranial pressure: causes?
3. Leads to watershed regions- what does that mean

Answer 12

1. Cardiogenic, septic, hemorrhagic
2. Edema, hemorrhage (subdural/subarachnoid)
3. Major cerebral/cerebellar artery perfusion territories are first to feel pinch when cerebral blood flow drops

Question 13

Define:

1. Cardiogenic shock
2. Septic shock
3. Hemorrhagic shock

Answer 13

1. Heart suddenly cannot pump enough blood to meet needs
2. Infection that leads to dangerously low BP
3. Due to depletion of intravascular volume thru blood loss (cannot match tissue demand)

Question 14

Hypoxic:

1. Theres enough __ but not enough __
2. Primary 3 cells that could be involved?

Answer 14

1. Enough blood flow but not enough oxygen

2. Hippocampus, neocortical pyramidal neurons, cerebellar purkinje neurons

Question 15

Timeline and major findings of the following kinds of hypoxic-ischemic lesions:

1. Acute
2. Subacute
3. Chronic, stage 1
4. Chronic stage 2

Answer 15

1. 1-4 days; blurring of white/gray matter junction, dead red neurons
2. 5-30 days; more prominent acute changes, cerebral edema, separation of gray from white matter, macrophages seen microscopically
3. Weeks-years; necrosis leading to cavity formation
4. Cystic cavity lined by firm wall

Question 16

1. What causes cytotoxic edema?

2. What causes excitotoxicity?

Answer 16

1. Failure of Na-K ATPase pump (Na and water go into cell too much)
2. Glutamate release increase

Question 17

Aneurysms:

1. 90% are what kind
2. Can have __ hemorrhage

Answer 17

1. Saccular=berry (congenital)(cerebral)

2. Subarachnoid

Question 18

Arteriovenous malformations:

1. What is it?
2. Major concern?
3. Hard to distinguish what on CT

Answer 18

1. Artery abnormally connects with a vein
2. Can get big and start to bleed
3. If its an artery or vein

Question 19

What parts of the brain do the following arteries supply:

1. Anterior cerebral artery
2. Vertebral and basilar arteries
3. Posterior cerebral artery

Answer 19

1. Medial portion of frontal and parietal lobes
2. Cerebellum and brainstem
3. Occipital lobe and some of temporal lobe and thalamus