Biology (Raven), 9th Edition

Chapter 44: The Nervous System

Post-Test

1
Schwann cells:
A)occur in the PNS.
B)produce a myelin sheath around axons.
C)are much smaller than neurons.
D)are supportive cells.
E)all of the above.
2
Action potentials:
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.
3
Inhibition of the enzyme acetylcholinesterase would cause:
A)build up of acetylcholine in the synaptic cleft.
B)build up of acetylcholinesterase in the synaptic cleft.
C)muscle relaxation.
D)repeated action potentials.
E)none of these.
4
Mammals have brains that are particularly large relative to their body mass. This is due to:
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.
E)the extension of the optic tracts
5
The parasympathetic effects of acetylcholine require:
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.
6
Interneurons:
A)occur in the central nervous system.
B)occur in the peripheral nervous system.
C)link afferent and efferent neurons.
D)occur in the central nervous system and link afferent and efferent neurons.
E)none of the above
7
When a neuron is not being stimulated it maintains:
A)a resting potential.
B)an action potential.
C)a charge difference across the cell membrane, with a positive charge inside the cell and negative outside.
D)a neutral state.
E)a resting potential and a charge difference across the cell membrane, with a positive charge inside the cell and negative outside.
8
Neurotransmitters:
A)are chemical signals.
B)are broken down slowly after they are released.
C)occur in gap junctions.
D)are released by the postsynaptic cell.
E)all of the above
9
The brains of fishes:
A)continue growing throughout their lives.
B)have a prominent hind brain.
C)have changed very little over 500 million years.
D)none of the above.
E)all of the above.
10
The peripheral nervous system:
A)has two divisions: the sympathetic and the asympathetic.
B)has two divisions: the somatic and the autonomic.
C)functions only to receive information from the environment.
D)functions only to carry responses to effectors (e.g. muscle cells).
E)utilizes interneurons to integrate efferent and afferent signals.
11
Nerve impulses are normally carried toward a neuron cell body by the neuron's
A)synaptic cleft.
B)axon.
C)myelin sheath.
D)neurotransmitter.
E)dendrites.
12
The spinal cord is part of the
A)somatic nervous system.
B)central nervous system.
C)parasympathetic nervous system.
D)sympathetic nervous system.
E)all of these.
13
Which of the following would allow a neuron to receive more stimuli?
A)more dendritic spines
B)more myelin sheath material
C)a larger cell body
D)a longer axon
E)more nodes of Ranvier
14
Which cells produce myelin in the peripheral nervous system?
A)sensory neurons
B)motor neurons
C)oligodendrocytes
D)Schwann cells
E)none of these
15
In a neuron that is at rest but ready to fire,
A)the inside and the outside of the neuron membrane have the same electrical charge.
B)the outside of the neuron membrane is more negatively charged than the inside.
C)the inside of the neuron membrane is more negatively charged than the outside.
D)any of these can be true; it varies among individual neurons.
E)is not using the sodium/potassium pump until after it fires.
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