1. Choose the set that includes the most charged compounds that are more abundant inside neurons, in the cytosol, than outside the neurons, in the extracellular fluid.
a) proteins and sodium ions
b) potassium ions and proteins
c) sodium and chloride ions
d) chloride ions and proteins
e) sodium and potassium ions
2. Select the choice that describes neurons with the fastest conduction velocity for action potentials.
a) thin, myelinated neurons
b) thick, myelinated neurons
c) thin, nonmyelinated neurons
d) thick, nonmyelinated neurons
e) All of these choices conduct action potentials at the same velocity.
3. Acetylcholine receptors on skeletal muscles are described as being "ionotropic" receptors because _____.
a) binding of acetylcholine to the receptor protein converts the protein to an open ion channel
b) binding of acetylcholine to its receptor triggers release of a second messenger, e.g., cAMP, inside the muscle
c) these receptors have a corequisite binding of magnesium ions in order to function
d) acetylcholine is an excitatory stimulus to the muscle
e) the receptors ionize as a result of binding acetylcholine, and this directly alters membrane potentials
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