Blood Brain Barrier Flashcards
% of the brain the ECF makes up
15-20
How does the brain control the composition of the ECF
- through CSF
- BBB protecting it from changes in blood composition
- glial cells conditioning the ECF
Name 5 functions of the CSF
- removes waste e.g. lactate
- acts as a cushion
- medium between ECF and blood
- right environment for neurones
- interface between brain and peripheral endocrine organs
How is CSF producted
ultrafiltration of plasma across fenestrated capillary into ECF in contact with basolat memb of CEC. choroid epithelial cells secreting fluid into the ventricles
describe what happens in the basolat membranes and the apical membranes
basolat- Na+ in causes H+ out. This causes HCO3 out and Cl IN
apical - 3Na out 2K in . electrochemical gradient causing HCO3- and CL- to leave cell INTO CSF
What is virchow robin space
filled with CSF. vessels take pia with them when they go into brain. cells lining have leaky junctions to allow the CSF and ECF to interact
how does the CSF interact with glia and neurones
via ECF
name two clinical uses of CSF for diagnosis
pathogens e.g. meningitis
hydrocephalus + sub arachnoid haemorrhage
name 3 factors that regulate the BBB and 2 properties of the BBB that enable this
lipid solubility, ionisation, plasma protein binding
tight junctions and net fenestrating
How does Dglucose Lleucine and Ldopa cross the BBB
through facilitated transport
How does the BBB effect parkinsons treatment and how do you get around this
L DOPA and a peripheral decarboxylase inhibitor - preventing conversion of ldopa to dopamine outside the brain. dopamine cant cross the BBB as its ionised at ph7.4
Name of the brain areas with a leaky the BBB
circumventricular organs
- post pituitary
- median eminence
- OVLT
- area postrema
