A dopamine pill is ineffective for treating Parkinson's disease because it ____.
A) is already present in too large an amount
B) does not cross the blood-brain barrier
C) would have to be the size of a baseball to be effective
D) is too expensive

Question

Quizplus · Accepted Answer

The blood-brain barrier prevents many substances, including dopamine, from crossing into the brain. Thus, a dopamine pill would not effectively treat Parkinson's disease.

A Dopamine Pill Is Ineffective for Treating Parkinson's Disease Because