Who uses it: Neurologists and pharmacologists
What it means: A membrane that keeps most toxins in the bloodstream from reaching the brain. It is the major reason that most infections don't reach the brain.
When you can use it: When ingesting things that aren't good for you. In case you were wondering, alcohol has little trouble with the blood-brain barrier.
This term has no specific relevance to me this morning, because I didn't go out last night; my back hurt too much, and I had too much work to do. Joseph stayed in too, we ordered a pizza, and I finished writing The Mystery Bookstore's massive April newsletter, which is the second-longest of the year.
I meant to do nothing today but work, but my back is not cooperating, again; I need to loosen it up enough to go to Annapolis this evening, so have spent a while in some serious stretches. Growing old isn't much fun.