Chapter 7 Quiz
false
A nerve is a bundle of axons in the CNS.
neurotrophins
Fetal neuron growth requires the actions of a group of chemicals known as 1) glutamates. 2) endorphins. 3) synapsins. 4) neurotrophins.
positive feedback
The mechanism that allows many Na+ ions to move into the axon is
saltatory conduction.
Conduction of an action potential in a myelinated axon is called 1) cable conduction. 2) saltatory conduction. 3) point to point conduction. 4) refractory conduction.
true
Conduction without decrement means that action potentials transmitted down an axon will not decrease in amplitude. 1) True 2) False
concentrated at the nodes of Ranvier.
In a myelinated axon, Na+ channels are 1) concentrated at the nodes of Ranvier. 2) along the whole length of the axon. 3) less numerous at the nodes of Ranvier. 4) every 5 mm.
voltage-gated channels.
Ion channels that open in response to depolarization are called 1) potential-gated channels. 2) ion-gated channels. 3) stimulation-gated channels. 4) voltage-gated channels.
multiple sclerosis.
The disease ______________ is characterized by destruction of CNS myelin sheaths and the formation of hardened scars. 1) myasthenia gravis 2) multiple sclerosis. 3) Parkinson's 4) Alzheimer's
node of Ranvier
The gap of exposed axon in the myelin sheath is the 1) neurilemma. 2) node of Ranvier. 3) white matter. 4) sheath of Schwann.
false
The greater the number of depolarization regions on an axon, the faster the action potential will be conducted. 1) True 2) False
potassium, sodium
The membrane of resting nerve cells is more permeable to ____________ ions than ____________ ions. 1) potassium, sodium 2) calcium, potassium 3) sodium, potassium 4) chloride, potassium
astrocytes
The most numerous of all cells of CNS nervous tissue are the 1) microglia 2) astrocytes. 3) neurons. 4) Schwann cells.
oligodendrocytes
The myelin sheaths of CNS neurons are produced by 1) oligodendrocytes. 2) ependymal cells. 3) Schwann cells. 4) leukocytes.
Schwann cells.
The myelin sheaths of PNS neurons are produced by 1) leukocytes. 2) ependymal cells. 3) Schwann cells. 4) oligodendrocytes.
true
Both depolarization and repolarization are produced by the diffusion of ions down their concentation gradient. 1) True 2) False
tract
A bundle of axons in the CNS is called a/an 1) nerve. 2) tract. 3) bundle. 4) neuron.
Schwann cells
Action potential transmission in the PNS is decreased if which cells are damaged? 1) astrocytes 2) oligodendrocytes 3) Schwann cells 4) microglia
true
Action potentials frequency encodes stimulus intensity.
true
All axons in the PNS are surrounded by Schwann cells.
false
All axons in the PNS have a myelin sheath. 1) True 2) False
false
An inactivated ion channel will respond to a strong stimulus.
recruitment
As the intensity of a stimulus increases, more axons will become activated. This process is called 1) threshold. 2) recruitment. 3) None apply. 4) refraction.
true
Astrocytes can be excited by changes in intracellular Ca2+ concentration.
satellite cells.
Cells supporting neuron cell bodies in ganglia are termed 1) ependymal cells. 2) satellite cells. 3) Schwann cells. 4) astrocytes.
false
Destruction of astrocytes would decrease the rate at which action potentials are transmitted. 1) True 2) False
false
During the absolute refractory period, a supramaximal stimulus can bring the cell to threshold.
binding to sodium channels.
Local anesthetics block conduction of action potentials in sensory neurons by 1) binding to calcium channels. 2) inhibiting the release of acetylcholine. 3) binding to potassium channels. 4) binding to sodium channels.
true
Most motor neurons are multipolar.
true
Myelinated axons transmit action potentials more rapidly than unmyelinated axons.
myelin sheath.
Regeneration of CNS axons may be prevented in part by inhibitory proteins in the membranes of the 1) myelin sheath. 2) astrocytes. 3) satellite cells. 4) neurons.
true
Retrograde axonal transport may be responsible for movement of herpes virus, rabies virus, and tetanus toxin from nerve terminals to the cell body.
true
Schwann cells and oligodendrocytes have similar functions.
false
Sensory nerves cause muscle contraction
are pseudounipolar and carry impulses toward the CNS.
Sensory neurons 1) are multipolar and carry impulses toward the CNS. 2) are multipolar and carry impulses away from the CNS. 3) are pseudounipolar and carry impulses toward the CNS. 4) are bipolar and carry impulses away from the CNS.
true
Sensory neurons for muscle position are the fastest conducting neurons. 1) True 2) False
false
Somatic motor neurons innervate involuntary effectors.
Repolarization and relative refractory period are correct.
The period of time when Na+ channels are recovering from their inactive state and K+ channels are still open is the 1) repolarization. 2) Repolarization and relative refractory period are correct. 3) absolute refractory period. 4) relative refractory period.
increased frequency of stimuli
What coding system do neurons use to get a greater response? 1) greater amplitude of stimuli 2) more active Na+/K+ pump 3) increased frequency of stimuli 4) greater Na+ concentration gradient
K+ is moving out of the axon through its open channels
What is NOT true of the relative refractory period? 1) K+ is moving out of the axon through its open channels 2) Na+ channels are inactivated 3) many Na+ channels are returning to a closed state 4) a strong stimulus could cause a depolarization
neurilemma
What structure is found around PNS axons that is NOT found around CNS axons? 1) neurilemma 2) plasma membrane 3) nodes of Ranvier 4) myelin sheath
Interneuron and association neuron are correct.
What type of neuron is found entirely in the CNS? 1) sensory neuron 2) interneuron 3) association neuron 4) Interneuron and association neuron are correct.
astrocytes
Which cells are needed for the formation of synapses in the CNS? 1) dendrites 2) ependymal 3) microglia 4) astrocytes
autonomic nervous system
Which division of the nervous system innervates involuntary effectors? 1) autonomic nervous system 2) associative nervous system 3) central nervous system 4) somatic nervous system
outward diffusion of K+
Which ion's movements is responsible for repolarization? 1) influx of Na+ 2) outward diffusion of Na+ 3) outward diffusion of K+ 4) influx of K+
phagocytose foreign material in the CNS
Which of the following is NOT a function of astrocytes? 1) can stimulate or inhibit neurons 2) phagocytose foreign material in the CNS 3) needed to form synapses in the CNS 4) form the blood-brain barrier 5) can take up neurotransmitters (NT) from a synapse
multipolar
Which of the following is NOT a functional classification of neurons? 1) interneuron or association 2) motor or efferent 3) multipolar 4) sensory or afferent
motor neuron
Which of the following is NOT a structural classification of neurons? 1) bipolar neuron 2) pseudounipolar neuron 3) motor neuron 4) multipolar neuron Question 6
ependymal cells
Which type of cell lines the ventricles of the brain and help produce cerebrospinal fluid? 1) oligodendrocytes 2) ependymal cells 3) satellite cells 4) microglia
microglia
Which type of cell of the CNS is phagocytotic? 1) microglia 2) oligodendrocytes 3) satellite cells 4) ependymal cells
myelinated axons in the CNS.
White matter is 1) myelinated axons in the PNS. 2) nonmyelinated axons in the CNS. 3) nonmyelinated cell bodies and dendrites in the CNS. 4) myelinated axons in the CNS.
