Which of the following is NOT correct with reference to the blood brain barrier?
-the barrier is permeable to glucose, alcohol, caffeine, nicotine, and anesthetic agents.
-the blood brain barrier is formed by the basement membrane and tight junctions between the
endothelial cells of the capillaries.
-the barrier is impervious to water, and prevents dehydration from affecting the brain.
-where the barrier is absent, HIV can enter the brain.