numbers

Question 1

how much CSF is produced in the brain?

Answer 1

20-25 ml in the ventricles; 700 ml in the system

Question 2

ion concentrations/composition

Answer 2

like blood but has higher concentrations of Na, Cl, Mg :
lower concentrations of K, Ca, glucose, protein.

glucose (50-80 mg per 100 ml)
protein (25-45 mg per 100 ml)

Question 3

blood flow to the brain

Answer 3

15-20% CO
80% from internal carotid a.
20% from vertebral a.

Question 4

energy req of brain

Answer 4

400 cal/day

Question 5

amount of time required before hypoxia causes irreversible damage

Answer 5

4-8minutes

Question 6

capillaries per cubic ml

Answer 6

100 caps/ml

Question 7

rate of cerebral blood flow

Answer 7

800 ml/min

Question 8

ischemic stroke types %

Answer 8

Ischemic Stroke (85% of all stroke): Hemorrhagic Stroke (15% of all strokes )

Large Artery Stenosis or Occlus. Thrombotic Stroke: 15%
Lacuna stroke 15%
Presumed Embolism: cardiac 20%, unknown 25%
Other 5-10%

Question 9

Hemorrhagic strokes

Answer 9

15% of all strokes

Parenchymal Hemorrhage 5-10%
Subarachnoid Hemorrhage 7%

Question 10

what causes watershed infarctions?

Answer 10

In global ischemia the distal areas of cerebral arterial circulation are hypoperfused, and vulnerable to watershed infarction. Certain areas of the brain (distal branches of the cerebral arteries) and particular neuronal population

Question 11

Regional Cerebral Blood Flow by Event : ~53 ml/100 gm tissue/min

Answer 11

Normal perfusion of neural tissue offers a generous margin of safety. Hypoxic symptoms appear when blood flow falls below 25-30 ml/100gm/min.

Question 12

Regional Cerebral Blood Flow by Event : < 18 ml/100 gm tissue/min

Answer 12

Electrical Failure
Tissue is viable, but there is cessation of brain electrical activity including attenuation of EEG and absence of cerebral evoked potentials.

Question 13

Regional Cerebral Blood Flow by Event : 10-20 ml/100 gm tissue/min

Answer 13

Ischemic Penumbra

Following focal ischemia (stroke) the tissue surrounding the core ischemic territory is too ischemic to function, yet critically viable. Stroke therapy is directed at rescuing
Ischemic

Penumbra by improving tissue acidosis and oxygen delivery. Calcium channel and NMDA receptor blocking drugs may prevent further neuronal damage.

Autoregulation dysfunction and edema due to ischemic tissue acidosis, and resultant “luxury perfusion” of adjacent normal tissue.

Question 14

Regional Cerebral Blood Flow by Event : < 10 ml/100 gm tissue/min

Answer 14

Ionic Failure

Irreversible tissue damage due to hypoperfusion. Failure of ATP dependent transport causes K+ to leak into the extracellular space, and the intracellular accumulation of Na+. Anaerobic metabolism results in some intracellular acidosis. Dying neurons may exacerbate cell injury and death by releasing glutamate (glutamate toxicity).

Question 15

Regional Cerebral Blood Flow by Event: 25-30 ml/100gm/min.

Answer 15

hypoxic symptoms