The "blood brain barrier" is primarily the result of
A)a number of astrocyte cells between the brain's extracellular space and the neurons
B)the brain capillaries' tightly packed endothelial cells and minimal pores
C)brain capillaries being separated from the blood vessels of the rest of the body
D)glial feet lining the brain's extracellular space

Question

Quizplus · Accepted Answer

The blood brain barrier is primarily the result of the tight junctions between endothelial cells of the brain capillaries, which prevent most solutes from crossing into the brain's extracellular space. This selective permeability is what protects the brain from potentially harmful substances in the blood. Other factors such as astrocyte cells and glial feet also play a role, but the main contributing factor is the tight packing of the endothelial cells.

The "Blood Brain Barrier" Is Primarily the Result of