Biology, Eighth Edition (Raven)

Chapter 44: The Nervous System

Post Test

Schwann cells: (p. 871)
A)occur in the PNS.
B)produce a myelin sheath around axons.
C)are much smaller than neurons.
D)both a and c
E)all of the above
Action potentials: (p. 876)
A)are all or none events.
B)occur when depolarization reaches a threshold potential.
C)result from the passive diffusion of ions.
D)are propagated along axons without a decrease in amplitude.
E)all of the above
Inhibition of the enzyme acetylcholinesterase would cause: (p. 880)
A)build up of acetylcholine in the synaptic cleft.
B)build up of acetylcholinesterase in the synaptic cleft.
C)muscle spasms.
D)repeated action potentials.
E)both a and c
Mammals have brains that are particularly large relative to their body mass. This is due to: (p. 886)
A)the enlargement of the cerebellum.
B)the enlargement of the cerebrum.
C)the enlargement of the whole brain.
D)the enlargement of the mesencephalon.
The parasympathetic effects of acetylcholine require: (p. 894)
A)the presence of modified receptors.
B)nothing, because they never, in fact, occur.
C)the action of G proteins.
D)an influx of Na+ ions into the cell.
E)an influx of K+ ions into the cell.
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