Question

question 8
1 pts
what is unique about the blood - brain barrier compared to other capillaries?

• endothelial cells are packed together in an abnormally dense fashion
• astrocytes attach to the blood vessels to provide extra insulation
• the phospholipid bilayers of cells in the blood - brain barrier are abnormally thick
• both a and b

Explanation:

The blood-brain barrier's key unique feature compared to regular capillaries is its tightly packed endothelial cells (with tight junctions) that restrict passage of substances, and astrocyte end-feet wrap around vessels to support this barrier function. The phospholipid bilayers are not abnormally thick.

Answer:

A. Endothelial cells are packed together in an abnormally dense fashion
B. Astrocytes attach to the blood vessels to provide extra insulation
C. Both A and B

Note: The correct selection is Both A and B as both the dense endothelial packing and astrocyte association are unique characteristics of the blood-brain barrier relative to typical capillaries.