Which of the following statements best describes the structure of the blood-brain barrier that provides its functional characteristics?
A)Processes of astrocytes wrap tightly around capillaries in the brain.
B)Tight junctions tightly seal endothelial cells of capillaries in the brain.
C)Gap junctions tightly seal endothelial cells of capillaries in the brain.
D)Spot desmosomes tightly link capillary endothelial cells together.
E)The basement membrane of capillaries in the brain contains extremely small pores.

Question

Quizplus · Accepted Answer

The blood-brain barrier is formed by tight junctions between endothelial cells of capillaries in the brain, which prevent the free movement of substances between the blood and brain tissue. This structure provides the functional characteristics of the blood-brain barrier. Processes of astrocytes also play a role in the blood-brain barrier, but they do not provide its structural characteristics. Gap junctions and spot desmosomes are not present in capillaries of the blood-brain barrier. The basement membrane of capillaries in the brain does not contain small pores, as these would compromise the barrier's function of selectively allowing certain substances to cross into the brain tissue.

Which of the Following Statements Best Describes the Structure of the Blood-Brain