試題詳解

9. Which of the following best describes a primary functional consequence of the blood-brain barrier (BBB) in regulating central nervous system homeostasis?
(A) It prevents the diffusion of small lipophilic molecules, ensuring strict metabolic control within the brain.
(B) It allows selective passive diffusion of hydrophilic neurotransmitters, facilitating rapid neuronal signaling.
(C) It restricts the entry of many circulating immune cells, limiting the brain's immune surveillance.
(D) It actively transports large plasma proteins into cerebrospinal fluid (CSF) to maintain osmotic balance.
(E) It permits the direct exchange of plasma and CSF without specialized transport mechanisms.