Question 1

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:&#10;A)blood-brain barrier.&#10;B)circle of Willis.&#10;C)glomerulus.&#10;D)septum pellucidum.&#10;E)corpus callosum.

Accepted Answer

The blood-brain barrier is a protective mechanism that prevents certain substances, including drugs, from passing from the bloodstream into the CNS. This is due to the unique structure of the capillaries in the CNS, which are tightly packed and surrounded by glial cells that prevent certain molecules from crossing over. The circle of Willis, glomerulus, septum pellucidum, and corpus callosum are not directly related to the blood-brain barrier.

Question 2

Drugs can alter CNS neurotransmission by affecting neurotransmitter:&#10;A)synthesis in the presynaptic terminal.&#10;B)release from the presynaptic terminal.&#10;C)degradation or breakdown at the synapse.&#10;D)reuptake into the presynaptic terminal.&#10;E)all of the above

Accepted Answer

Drugs can affect CNS neurotransmission in all of the mentioned ways. They can either enhance or inhibit neurotransmitter synthesis, release, breakdown, or reuptake, which in turn affects the overall neurotransmission process in the CNS.

Question 3

All of the following substances are considered CNS neurotransmitters EXCEPT:&#10;A)monoamines such as norepinephrine.&#10;B)second messengers such as cyclic AMP.&#10;C)amino acids such as glycine.&#10;D)hormones such as vasopressin.&#10;E)acetylcholine.

Accepted Answer

Second messengers such as cyclic AMP are not themselves considered CNS neurotransmitters, but instead play a role in intracellular signaling cascades initiated by neurotransmitters or other signaling molecules. The other options listed are all examples of neurotransmitters that are involved in CNS signaling.

Deck 5: Central Nervous System Pharmacology: General Principles