Biology (Raven), 10th Edition

Chapter 43: The Nervous System


Which is a true comment concerning Schwann cells?
A)are found in the PNS
B)produce a myelin sheath around axons
C)are roughly one-tenth the size of neurons
D)are neuroglia
E)All selections are correct.
Which statement is NOT correct concerning action potentials?
A)are all or none events
B)occur when depolarization reaches a threshold potential
C)do not add or interfere with one another
D)are propagated along axons with a decrease in amplitude
E)All of the selections are correct.
If the enzyme acetylcholinesterase were inhibited in postsynaptic membranes, what would be the consequence?
A)accumulation of acetylcholine in the synaptic cleft
B)accumulation of acetylcholinesterase in the synaptic clef
C)muscle relaxation
D)repeated action potentials
E)None of the selections is correct.
Mammals have evolved brains that are particularly large relative to their body mass. This is due to the enlargement of which part of the mammalian brain?
A)the cerebellum
B)the cerebrum
C)the whole brain
D)the mesencephalon.
E)the optic tracts
What is required for acetylcholine to inhibit pacemaker cells in the heart?
A)the presence of modified receptors
B)nothing, because it doesn't act on pacemaker cells
C)G protein-coupled receptors
D)an influx of Na+ ions into the cell
E)an influx of K+ ions into the cell.
Which is a true comment about 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)There are no true comments.
What state is maintained in a neuron that is not being stimulated?
A)a resting potential
B)an action potential
C)a charge difference across the cell membrane, with a positive charge inside the cell and a negative one 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 a negative one outside
Which is a true statement about neurotransmitters?
A)They are chemical signals.
B)Neurotransmitters are broken down slowly after they are released.
C)They occur in gap junctions.
D)They are released by the postsynaptic cell.
E)All statement are true.
Which is a true statement about the the brains of fishes?
A)The continue to grow throughout their lives
B)Fish brains have a prominent hind brain.
C)Fish had three characteristic brain divisions over 500 million years.
D)No selections are true.
E)All selections are true.
Which statement is true concerning the peripheral nervous system?
A)It has two divisions: the sympathetic and the asympathetic.
B)It has two divisions: the somatic and the autonomic.
C)It functions only to receive information from the environment.
D)It functions only to carry responses to effectors (e.g. muscle cells).
E)It utilizes interneurons to integrate efferent and afferent signals.
Which part of a neuron carries impulses toward the cell body?
A)synaptic cleft
C)myelin sheath
The spinal cord is part of which division of the nervous system?
A)somatic nervous system
B)central nervous system
C)parasympathetic nervous system
D)sympathetic nervous system
E)All answers are correct.
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
Which cells produce myelin in the peripheral nervous system?
A)sensory neurons
B)motor neurons
D)Schwann cells
E)None of the answers is correct.
What is the state of 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)All of the answers are correct because of variations among individual neurons.
E)The sodium/potassium pump begins to operate only after a neuron fires.
True or false: Chemical synapses involves gap junctions.
Which part of a postsynaptic neuron integrates EPSPs and IPSPs arising from a number of presynaptic neurons?
B)cell body
D)the entire neuron
Name a neurophysiologically active chemical and the amino acid from which it is derived.
A)serotonin derived from glycine
B)epinephrine derived from tryptophan
C)acetylcholine derived from cysteine
D)epinephrine derived from tyrosine
Which statement is NOT correct concerning reflexes?
A)Eyelid blinks are reflexes, and they are so fast they happen before the brain realizes what happened.
B)The cutaneous spinal reflex is faster than the knee jerk reflex.
C)The knee jerk reflex involves a monosynaptic synapse.
D)Interneurons in reflexes are found in the gray matter.
E)Reflexes are involuntary movements.
Which is a correct list of the cerebral lobes?
A)dorsal, ventral, lateral and medial
B)parietal, frontal, dorsal, occipital
C)motor, sensory, associative and integrative
D)frontal, parietal, temporal and occipital
Which is a correct description of the corpus callosum?
A)It is a part of the ventricular system.
B)It divides the frontal lobe from the parietal lobe.
C)It connects the right and left cerebral hemispheres.
D)It is an extension of the brain stem.
True or false: the cellular basis of learning and memory apparently involves long-term changes in the strength of synaptic connections.
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