Chapter 7 Quiz

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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.


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