Step I First Aid 2005 pg 94 help.

[skidmark]

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I don't understand the blood brain barrier picture. My problem is that it is showing choroid epithelim next to arachnoid???? and then a fenestrated blood vessel??

Isnt the choroid epithelium the Blood-CSF barrier?

And isn't the BBB just a NON-fenestrated cappillary and astrocytes?

Am I totally reading this picture wrong? Are the three structures illustrated in anatomical position or are they just showing them individually?

Please help.

 

[viper]

While you wait for an official answer - I remember some friends saying that the picture is incorrect. I briefly looked at it and agree (but have not checked it out in detail). So I would say you are looking at it correctly, there is possibly an error.

 

[viper]

Looked at it very carefully (very very carefully) - it is correct. If you don't see it, then PM me and I will explain it in detail after friday. Sorry time-crunched right now.

Take care,

 

[JMD]

The picture is a little bit wrong...

It is actually a diagram of the blood-CSF barrier, but most blood vessels in the brain are not that close to the CSF. The rest of the blood brain barrier is made up of nonfenestrated endothelial cells and astrocytes foot processes.

So, if you just change the word "brain" to "CSF" in the title of the diagram, then it is correct.

HY Neuro makes the distinction on p. 50.

 

[dcpark74]

The human brain by Nolte, PhD states that there are 3 barriers associated with the common term 'blood-brain barrier.'

1. extracerebral capillaries (substances from them cannot cross arachnoid layer); 'arachnoid barrier'
2. intracerebral capillaries 'true blood brain barrier' (substances cannot leak out due to tight junctions EXCEPT circumventricular organs: neurohypophysis, pineal gland, hypothalamus, median eminence; hormones and stuff)
3. choroidal capillaries (substances from them cannot cross choroid epithelium); 'blood-CSF barrier'

of course, these are selectively permeable like first aid said to glucose, aa's, lipid soluble molecules (3rd gen ceph's), etc.

hope this helps...