Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 9

Substances present in the CSF are controlled by the:

A. Arachnoid granulations

B. Blood–brain barrier

C. Presence of one-way valves

D. Blood–CSF barrier

Step 1 of 2

Blood-brain barrier:

• Choroid plexus forms cerebrospinal fluid (CSF) from the plasma through selective filtration mechanisms under active transport secretion, and hydrostatic pressure

• Choroid plexus have endothelial cells that consists of tight-fitting junctures

• These junctures are called blood-brain barrier, which do not allow passage of many molecules

• Blood-brain barrier integrity should be maintained to protect the brain from chemical substances present in the circulating blood

• This barrier also prevents passage of medications, and antibodies

Therefore, “blood-brain barrier” controls the substances in CSF. Hence, the correct answer is option.