BBB Flashcards
what are the roles of the skull and vertebral column
physical protection of brain and spinal cord
what are the roles of the meninges
protective membranes all the way around the brain and spinal cord
what are the structure of the meninges
dura mater - outer membrane
arachnoid mater - highly vascularised layer
pia mater - gentle, thin, innermost membrane
what are the roles of cerebrospinal fluid
Brain floats within it - cushioning and shock absorbed
what is the BBB
○ Between the blood and neural tissues
○ High selective
○ Limits access from blood
what are the two extracellular fluid compartments in the brain
CFS - ventricles and central canal of spinal cord
interstitial space - surrounding the CNS cells
what are ventricles
§ Ventricles are CSF filled cavities within the brain - 4 in total
□ 2 lateral, one central and one in the brain stem
Lined with ependymal cells - ciliated for CSF flow
what is the role of CSF
shock absorber
exchanges with interstitial fluid
highly regulated content - low k and higher na
where does CSF come from
§ Secreted by epithelial cells of the choroid plexuses in the ventricles - selective transport mechanisms
Drains into the subarachnoid space and then out via arachnoid villi into dural sinus
how is the BBB regulated
○ K+ levels can change in the blood but it will not change the levels in the interstitial fluid
Keeps unwanted substances out - hormones, neurotransmitters etc in the periphery
what are the differences between the brain capillary and general capillary
tight junctions - no gaps
pericytes control movement
astrocyte foot processes maintain tight junctions
substances must pass THROUGH endothelial cell
which organs are not inside of the bbb
circumventricular organs
- posterior pituitary - secretes protein hormones that need to get to the rest of the body
- area postrema - chemoreceptor trigger zone causing vomiting
how are circumventricular organs isolated from the bbb
tanycytes - tanycytic membrane
