Blood Brain Barrier

Question 1

ECF accounts for how much of the brain volume?

Answer 1

15%

Question 2

Increase in what during synaptic activity?

Answer 2

Glutamate, and k+ causing depolarisation.

Question 3

CSF synthesised by what?

Answer 3

Choroid plexus.

Question 4

what is the choroid plexus made of?

Answer 4

specialised glial cells

Question 5

What does the BBB protect the ecf from?

Answer 5

fluctuations in blood composition and limits the entry of compounds in ecf.

Question 6

what is the function of the csf?

Answer 6

provide an appropriate local environment for neurons and glia by maintaining appropriate concs. of salt.

Question 7

what is the median of exchange between the brain ecf and systemic blood?

Answer 7

csf

Question 8

what is the main waster product removed by the csf?

Answer 8

lactate

Question 9

forms thin layer around brain and spinal cord in what space?

Answer 9

sub arachnoid space

Question 10

what connects the right and left lateral ventricles to the 3rd ventricle?

Answer 10

foramina of monroe.

Question 11

what does the cerebral aquaduct connect?

Answer 11

3rd and 4th ventricle.

Question 12

formaina of lushka allows what?

Answer 12

csf into subarachnoid space in brain

Question 13

what allows csf down into spinal cord?

Answer 13

foramina of majendee.

Question 14

what are the two ways csf is made?

Answer 14

ultra-filtration of plasma across the fenestrated capillary wall into ecf beneath the basolateral membrane of choroid epithelial cell.
choriod epithelial cells secrete fluid into the ventricles.

Question 15

what is the basolateral side important for?

Answer 15

neutralising acids produced by cns cells

Question 16

what important pump is in the apical membrane?

Answer 16

Na+-K+ ATPase pump, responsible for the Na+ efflux into the CSF.

Question 17

what is the net effect of secretion?

Answer 17

increased Na+ outside the cell drags Na+ from the other side.

Question 18

where does absorption of csf occur?

Answer 18

arachnoid villi within the subarachnoid space.

Question 19

how does absorption of csf occur?

Answer 19

a) bulk flow via arachnoid villi 500 mls/day
b) diffusion
c) active transport

Question 20

what is the function of arachnoid granulations?

Answer 20

small protrusions of arachnoid through the dura mata, protrude into venous sinuses and allow the csf to exit subarachnoid space and enter the blood stream.

Question 21

what is a virchow robin space?

Answer 21

immunological space between the pia and capillary. expanded by leucocytes - space is formed when large vessel takes pia with them diving into the brain - fills with leucocytes, found in pts with viral encephalitis.

Question 22

what is different about the capillary endothelium cells of the brain capillaries?

Answer 22

they have tight junctions and not fenestrations. limits access to larger molecules.

Question 23

if lipid solubility is increased then is there more or less of a chance of it accessing the brain?

Answer 23

more

Question 24

what are organs called not covered by the BBB?

Answer 24

Circumventricular organs - tight junctions replaced by normal fenestrated endothelia.

Question 25

What are the 4 organs in the brain?

Answer 25

posterior pituitary, median eminence, area postrema, OVLT(Organum vasculosum laminae terminalis).