Which of the following can readily cross the blood-brain barrier?
I.CO₂ molecules
II.Bicarbonate ions
III.H+ ions
A) I only
B) II only
C) I and III only
D) II and III only

Question

Quizplus · Accepted Answer

CO₂ molecules are small and nonpolar, which allows them to easily cross the blood-brain barrier. Bicarbonate ions and H+ ions are charged and therefore have difficulty crossing the barrier.

Which of the Following Can Readily Cross the Blood-Brain Barrier