Respuesta :
Answer:
The barrier functions to regulate the chemical composition of the extracellular fluid surrounding the brain cells.
Explanation:
Blood-brain barrier
It is a very selective semipermeable membrane , hence allow some specific substance to pass via it . This barrier separates the extracellular fluid in the central nervous system and the circulating blood from the brain .
The barrier is composed of the endothelial cells .
Passive diffusion is shown in this system , and allows molecules like the water , glucose , amino acid to pass .
It regulates the chemical composition of the fluid of brain cell .
