The Blood-Brain Barrier

Question

The blood-brain barrier
A)prevents the passage of all substances.
B)prevents the passage of lipid soluble substances.
C)is the innermost meningeal membrane.
D)is comprised of tightly joined endothelial cells in capillaries.
E)is responsible for the production of cerebrospinal fluid.

Accepted Answer

The blood-brain barrier is comprised of tightly joined endothelial cells in capillaries, which prevent the passage of certain substances from the bloodstream into the brain tissue.

Answer: B 
 The blood-brain barrier does not prevent the passage of all substances, but rather only prevents the passage of lipid-soluble substances, such as certain drugs and toxins, from entering the brain tissue.

Answer: C 
 The meninges are the three protective membranes that surround the brain and spinal cord, including the dura mater (outermost layer), arachnoid mater (middle layer), and pia mater (innermost layer). The blood-brain barrier is not one of these layers.

Answer: E 
 The production of cerebrospinal fluid is not directly related to the blood-brain barrier, which is responsible for regulating the passage of certain substances from the bloodstream into the brain tissue.