This first-pass effect is of particular concern when drugs are administered

This first-pass effect is of particular concern when drugs are administered:
A)   topically.
B)   intravenously.
C)   subcutaneously.
D)   by inhalation.
E)   orally.

Drugs can alter CNS neurotransmission by affecting neurotransmitter:
A)   synthesis in the presynaptic terminal.
B)   release from the presynaptic terminal.
C)   degradation or breakdown at the synapse.
D)   reuptake into the presynaptic terminal.
E)   all of the above

Certain drugs are not able to pass from the bloodstream into the CNS because of the unique structure and function of the CNS capillaries, known commonly as the:
A)   blood-brain barrier.
B)   circle of Willis.
C)   glomerulus.
D)   septum pellucidum.
E)   corpus callosum.