The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________.
depolarization
repolarization
absolute refractory period
resting period
absolute refractory period
Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?
leakage channel
mechanically gated channel
ligand-gated channel
voltage-gated channel
voltage-gated channel
Saltatory conduction is made possible by ________.
diphasic impulses
large nerve fibers
erratic transmission of nerve impulses
the myelin sheath
the myelin sheath
When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________.
postsynaptic potential
excitatory potential
generator potential
action potential
generator potential
Which of the following is not true of graded potentials?
They can be called postsynaptic potentials.
They are short-lived.
They can form on receptor endings.
They increase amplitude as they move away from the stimulus point.
They increase amplitude as they move away from the stimulus point.
A second nerve impulse cannot be generated until ________.
the Na ions have been pumped back into the cell
all sodium gates are closed
proteins have been resynthesized
the membrane potential has been reestablished
the membrane potential has been reestablished
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________.
positively charged and contains more sodium
negatively charged and contains less sodium
negatively
negatively charged and contains less sodium
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________.
the impulse would move to the axon terminal only
muscle contraction would occur
the impulse would spread bidirectionally
the impulse
the impulse would spread bidirectionally
A patient is admitted to the hospital with exacerbation of multiple sclerosis (MS). She asks the nurse "Why did this have to happen to me again? I was doing so well." Why are some forms of MS characterized by periods of remission and exacerbation?
The axo
The axons are not damaged; growing numbers of sodium channels appear spontaneously in the demyelinated fibers, allowing conduction to resume.
Correct
Graded potentials originating in the dendrites and cell body are integrated (summated) at the axon hillock (C). Membrane potentials above threshold at the hillock will open voltage gated Na+ channels found in the "trigger zone," producing an actio
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In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.
True
False
true
Axon diameter and degree of myelination determine nerve impulse conduction velocity.
True
False
true
The action potential is caused by permeability changes in the plasma membrane.
True
False
true
What does the central nervous system use to determine the strength of a stimulus?
origin of the stimulus
type of stimulus receptor
size of action potentials
frequency of action potentials
frequency of action potentials
Immediately after an action potential has peaked, which cellular gates open?
calcium
chloride
potassium
sodium
potassium
Which of the following is true about the movement of ions across excitable living membranes?
Ions always move actively across membranes through leakage channels.
Ions always move passively across membranes.
Sodium gates in the membrane can open in respons
Sodium gates in the membrane can open in response to electrical potential changes.
The __________ is due to the difference in K+ and Na+ concentrations on either side of the plasma membrane, and the difference in permeability of the membrane to these ions.
active potential
intermittent membrane potential
dendrite potential
resting membr
resting membrane potential
What type of stimulus is required for an action potential to be generated?
a suprathreshold stimulus
hyperpolarization
a threshold level depolarization
multiple stimuli
a threshold level depolarization
Which of the following is NOT true of an electrical synapse?
Transmission across these synapses is very rapid.
Communication through these synapses may be unidirectional or bidirectional.
They are specialized for release and reception of chemical neurotra
They are specialized for release and reception of chemical neurotransmitters.
Which of the following is NOT a type of circuit?
pre-discharge circuits
reverberating circuits
diverging circuits
converging circuits
pre-discharge circuits
Which of the following circuit types is involved in the control of rhythmic activities such as the sleep-wake cycle, breathing, and certain motor activities (such as arm swinging when walking)?
diverging circuits
parallel after-discharge circuits
reverber
reverberating circuits
In a synapse, neurotransmitters are stored in vesicles located in the __________.
postsynaptic neuron
synaptic cleft
presynaptic neuron
presynaptic neuron
An action potential releases neurotransmitter from a neuron by opening which of the following channels?
voltage-gated Ca2+ channels
chemically gated Ca2+ channels
voltage-gated Na+ channels
voltage-gated K+ channels
voltage-gated Ca2+ channels
Binding of a neurotransmitter to its receptors opens __________ channels on the __________ membrane.
chemically gated; presynaptic
voltage-gated; presynaptic
voltage-gated; postsynaptic
chemically gated; postsynaptic
chemically gated; postsynaptic
Binding of the neurotransmitter to its receptor causes the membrane to __________.
either depolarize or hyperpolarize
hyperpolarize
depolarize
either depolarize or hyperpolarize
The mechanism by which the neurotransmitter is returned to a presynaptic neuron's axon terminal is specific for each neurotransmitter. Which of the following neurotransmitters is broken down by an enzyme before being returned?
glutamate
acetylcholine
acetylcholine
The small space between the sending neuron and the receiving neuron is the
synaptic cleft.
synaptic terminal.
calcium channel.
neurotransmitter.
vesicle.
synaptic cleft.
A molecule that carries information across a synaptic cleft is a
synaptic cleft.
sending neuron.
neurotransmitter.
receiving neuron.
synapse.
neurotransmitter.
When calcium ions enter the synaptic terminal,
they cause an action potential in the sending neuron.
the inside of the receiving neuron becomes more negative.
they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the
they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.
When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron,
ion channels in the plasma membrane of the receiving neuron open.
the receiving neuron becomes more negative inside.
vesicles in the synaptic terminal fuse t
ion channels in the plasma membrane of the receiving neuron open.
If a signal from a sending neuron makes the receiving neuron more negative inside,
the receiving neuron immediately generates an action potential.
the sending neuron becomes more positive inside.
the sending neuron becomes more negative inside.
the receiv
the receiving neuron is less likely to generate an action potential.
A postsynaptic cell can be a neuron, a muscle cell, or a secretory cell. What is an example of a presynaptic cell?
a muscle cell
a Schwann cell
a neuron
a secretory cell
a neuron
Which component has a role in the postsynaptic cell during synaptic activity?
calcium channels
Vesicles filled with neurotransmitter
axon terminal
chemically gated channels
chemically gated channels
What is the role of calcium in synaptic activity?
Calcium diffuses across the synaptic cleft and binds to receptors on the postsynaptic neuron.
Calcium influx into the synaptic terminal causes vesicle fusion.
Calcium degrades neurotransmitter in the synap
Calcium influx into the synaptic terminal causes vesicle fusion.
What is the role of neurotransmitter at a chemical synapse?
Neurotransmitter causes vesicles to fuse with the presynaptic membrane.
Neurotransmitter binds to receptors on the postsynaptic cell membrane and allows ions to diffuse across the membrane.
Neuro
Neurotransmitter binds to receptors on the postsynaptic cell membrane and allows ions to diffuse across the membrane.
Neurotransmitter is released from presynaptic neurons through what mechanism?
exocytosis
phagocytosis
pinocytosis
endocytosis
exocytosis
What type of channel on the postsynaptic membrane binds neurotransmitter?
a mechanically gated channel
a leakage channel
a voltage-gated channel
a chemically gated channel
a chemically gated channel
In addition to diffusion, what are two other mechanisms that terminate neurotransmitter activity?
reuptake and degradation
exocytosis and degradation
excitation and degradation
reuptake and inhibition
reuptake and degradation
Events that occur during synaptic activity are listed here, but they are arranged in an incorrect order. Choose the correct order of these events below. (a) Voltage-gated calcium channels open (b) Neurotransmitter binds to receptors (c) Action potential a
(c) Action potential arrives at axon terminal (a) Voltage-gated calcium channels open (e) Neurotransmitter released into synaptic cleft (b) Neurotransmitter binds to receptors (f) Graded potential generated in postsynaptic cell (d) Neurotransmitter is rem
A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane.
True
False
true
An impulse from one nerve cell is communicated to another nerve cell via the ________.
receptor
cell body
effector
synapse
synapse
Which of the following is false or incorrect?
An inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane.
An excitatory postsynaptic potential occurs if the excitatory eff
A nerve impulse occurs if the excitatory and inhibitory effects are equal.
An inhibitory postsynaptic potential (IPSP) is associated with ________.
lowering the threshold for an action potential to occur
opening of voltage-regulated channels
a change in sodium ion permeability
hyperpolarization
hyperpolarization
Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane?
A single type of channel will open, permitting simultaneous flow of sodium and potassium.
Sodium gates will open first, then c
A single type of channel will open, permitting simultaneous flow of sodium and potassium.
Select the correct statement regarding synapses.
Neurotransmitter receptors are located on the axons terminals of cells.
The release of neurotransmitter molecules gives cells the property of being electrically coupled.
Cells with gap junctions use chemica
the synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
Which of the following correctly describes a graded potential?
amplitude of various sizes
long distance signaling
voltage stimulus to initiate
voltage regulated repolarization
amplitude of various sizes
Which of the following describes the excitatory postsynaptic potential?
moves membrane potential away from threshold
opens K+ or Cl- channels
short distance hyperpolarization
short distance depolarization
short distance depolarization
Which membrane potential occurs because of the influx of Na+ through chemically gated channels in the receptive region of a neuron?
action potential
inhibitory action potential
excitatory postsynaptic potential
inhibitory postsynaptic potential
excitatory postsynaptic potential
Which of the following is NOT one of the chemical classes into which neurotransmitters fall?
peptides
gases and lipids
amino acids
chlorides
chlorides
Which pattern of neural processing works in a predictable, all-or-nothing manner, where reflexes are rapid and automatic responses to stimuli in which a particular stimulus always causes the same response?
oscillative processing
reflexive processing
seria
serial processing
The substance released at axon terminals to propagate a nervous impulse is called a(n) ________.
cholinesterase
ion
neurotransmitter
biogenic amine
neurotransmitter
What is the role of acetylcholinesterase?
act as a transmitting agent
amplify or enhance the effect of ACh
destroy ACh a brief period after its release by the axon endings
stimulate the production of acetylcholine
destroy ACh a brief period after its release by the axon endings
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?
gamma aminobutyric acid
norepinephrine
cholinesterase
acetylcholine
acetylcholine
Some neurotransmitters can be either excitatory or inhibitory depending upon the receptor.
True
False
true
Which selection correctly describes the role of calcium in coupling?
Calcium binds to actin, which triggers troponin to fall off and expose myosin-binding sites.
Calcium binds to tropomyosin, which moves tropomyosin and exposes the myosin-binding sites on
Calcium binds to troponin, which moves tropomyosin and exposes the myosin-binding sites on actin.
Which best describes the initial event in contraction?
Myosin heads bind to the newly exposed myosin-binding sites on actin to form cross bridges.
The myofilaments slide closer together.
Tropomyosin binds to myosin heads and actin bridges with tropomyosin
Myosin heads bind to the newly exposed myosin-binding sites on actin to form cross bridges
Which of the following statements best summarizes excitation-contraction coupling?
A series of events in which an electrical stimulus is conveyed to a muscle fiber to enact contraction.
A series of events in which actin binds myosin to enact contraction.
A series of events in which an electrical stimulus is conveyed to a muscle fiber to enact contraction.
1.
Correct Which anatomical division of the nervous system consists of the brain and spinal cord?
Your Answer:
central nervous system
2.
Correct Which functional division of the nervous system controls skeletal muscle contractions?
Your Answer:
somatic ne
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1.
Match the following terms with their correct definitions.
Option
Your Answer
1.1
Correct CNS D. This location-based division of the nervous system contains the brain and spinal cord.
1.2
Correct ANS B. A component of the efferent division of the nervou
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BIO 1121 Chapter 12 Neural Tissue
Nervous System Overview
Two communications systems in the body:
1. Nervous system
� Provides swift, brief responses to stimuli
2. Endocrine system
� Adjusts metabolic operations and directs long-term changes
Nervous syste
...
1.
Correct The central nervous system consists of the __________.
Your Answer:
brain and spinal cord
2.
Incorrect Which of the following statements about the nervous system is FALSE?
Your Answer:
The sympathetic and parasympathetic divisions of the autono
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1.
Incorrect The ependymal cells line the blood vessels that supply the neural tissues of the brain, thereby forming the blood-brain barrier.
Your Answer:
True
Correct Answer:
False
Incorrect. Ependymal cells line the central canal and brain ventricles an
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Amy wants to text-message her friend Michelle. Amy sends impulses from her brain to the skeletal muscles in her arms and hands, enabling her to correctly punch the buttons on her phone to create the text message. The type of axon fibers Amy is using to se
...
1.
Correct Which part of the nervous system performs the higher-order thinking required to complete this practice exam?
Your Answer:
central nervous system
2.
Incorrect Which of the following structures is NOT part of the PNS?
Your Answer:
a sensory recep
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Neural Activities:
Resting potentialAt rest, the cell uses energy to maintain a difference in charge on either side of the membrane. The inside of the membrane is negative relative to the outside of the membrane. This difference is the membrane potential.
...
Neural Tissue - Nervous System
Central nervous system:
The brain and spinal cord
Peripheral nervous system:
The nervous system outside the brain and spinal cord; consists mostly of nerves and
ganglia
Sensory input:
A neural signal from a sensory receptor
...
Efferent neurons transmit impulses from:
CNS to Effectors
The Nodes of Ranvier are:
Gaps in Myelin Sheath
Cells responsible for information processing and transfer are:
Neurons
Interneurons
Are found mostly in the central nervous system
Most integration occurs in the:
CNS (central nervous system)
Graded Potentials
1 / 8 resting membraneThe resting membrane potential is maintained when the neuron is not sending an impulse. Changes in this potential represent signals. Either a chemical or environmental stimulus causes a change in the membrane permea
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Neural Tissue - Neurophysiology
Resting membrane potential:
The difference in electrical charge across an inactive cell membrane; measured in
millivolts
Polarized:
Having a difference in electrical charge; an inactive cell membrane is polarized
Depolariza
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A postsynaptic potential which involves hyperpolirization;
is inhibitory
The term saltatory conduction refers to the:
conduction of a nerve impulse along a myelinated axon.
The signal which inhibits generation of an action potential is:
hyperpolarization
A neurotransmitter which functions through direct action:
changes the permeability of the membrane
Cholinergic synapses release:
acetylcholine