Chapter 11
Reflexes are rapid, automatic responses to stimuli.
True
Sub neurotransmitter can be either excitatory or inhibitory depending upon the receptor
True
Which of the following will occur when an excitatory postsynaptic potential EPSP is being generated on the dendritic remembering
A Single type of channel will open, permitting simultaneous flow of sodium and potassium.
Which of the following is false or incorrect?
A nerve impulse occurs if the excitatory and inhibitory effects are equal.
Which if the following neurotransmitters is broken down by enzyme before being returned?
Acetylcholine
Which of the following is an excitatory neurotransmitter secreted by motor neuron innovating skeletal muscles?
Acetylcholine
Which of the following is true regarding a response to an excitatory Event which might occur soon after the Initial stimulus
An excitatory Event to may result in an action potential, but will be less likely if excitatory Stimulus occurs during response to stimulus observers
What conditions Will increase the diffusion of molecules, such as neurotransmitters
An increase in the amount of neurotransmitter exocytized by the presynaptic axon.
subthreshold stimulus
An insufficient stimulus.
threshold stimulus
Any stimulus below this intensity will result in no response in a neuron.
Nerve cell adhesion molecules (N-CAMs) ________.
Are crucial for development of neural connections
What are some form of MS characterized the period of remission and exacerbation
Axons aren't damaged, growing number of sodium channels appear spontaneously in the demyelinated fibers, Allowing conduction to resume.
Which of the following statements is true of both membrane potential responses
Both responses are of graded potential.
What is the role of calcium in synaptic activity
Calcium influx into the synaptic terminal causes vesicle fusion.
Which component has a rule in postsynaptic cell during synaptic activity
Chemically gated channels
Line Going down and up
Closure of voltage-gated K+ channels
Which factor that determines rate of impulse propagation, or conduction velocity, along an axon?
Degree of myelination of axon
chemical synapse
Dendrite, cell body, axon hillock, axon, presynaptic terminal
A line going down on a graph
Diffusion of K+ out of axon through gated ion channels
Binding of a neurotransmitter to its receptors causes membrane to_____
Either depolarize or hyperpolarize
Which of the following neurotransmitter inhabit pain and is mimicked by morphine, heroin, and methadone?
Endorphin
Neurotransmitter Is released from presynaptic neuron through what Mechanism
Exocytosis
Strong stimuli cause the amplitude of action potentials generated to increase.
False
The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place.
False
Unmyelinated fibers conduct impulses faster than myelinated fibers.
False
Oilgodendrocytes
Forms myelin sheaths within white matter if CNS
Which of the following is the clearest example of neuronal membranes selective permeability
K+ ions can diffuse across the membrane more easily than Na+ ions.
Predict the possible effect of curare On postsynaptic membrane and muscle.
Local graded potentials and action potential transmission is blocked and there is no response by postsynaptic cell, muscle
What is the major role of the NA+ -K+ Pump in maintaining the resetting membrane potential
Maintaining the contraction gradients for na+ and k+ Across the cell membrane
Which statement best describes exocytosis
Membrane organelles fuse with the membrane and release contents out of the cell.
Which of the following is not true of association neurons
Most association neurons are confined within the peripheral nervous system (PNS).
Which following types of neurons carry impulses away from central nervous system?
Motor
Which of the following is not as functional classification of neurons
Multipolar
What is the direct role of neuron transmitter at a chemical synapse
Neurotransmitter binds to receptors On postsynaptic cell membrane and allows ions to diffuse across membrane
temporal summation
Numerous nerve impulses arriving at a synapse at closely timed intervals exert a cumulative effect
Which of the following types of glial Cells produce is the myelin sheaths that insulate axons, Or nerve fibers, in the central nervous system
Oligodendrocytes
Responses of left graph arrow going up is
Opening of gate Na+ channels
threshold value indicated at -55mV
Opening of voltage gated Na+ channels
Immediately after an action potential has peaked, which cellular gates open?
Potassium
In synapse, neurotransmitters are stored in vesicles located in __________.
Presynaptic neuron
Which of the following is not one of the basic function of nervous system.
Regulation of neurogenesis
The_______is due to deference in K+ and Na+ concentrations on either side of plasma membrane and difference in permeability of membrane to these ions
Resting membrane potential
Which of the following peripheral Nervous system neuroglia Form myelin sheaths around nerve fibers in PNS
Schwann cells
Which of the following describes the sodium and potassium Contractions across a neurons plasma membrane
Sodium contraction is higher Outside the cell compared to inside. Potassium is Hi are inside the cell compared to outside
Which of the following is true about the movement of ions across excitable living membranes
Sodium gates in the membrane can open in response to electrical potential changes.
Which of the following is Not a difference between greater potentials and action potential
Spatial summation is used to increase amplitude if grades potential; temporal summation used to increase amplitude of action potential
spatial summation
Stimulation of a postsynaptic neuron by many terminals at the same time.
The action potential is caused by permeability changes in plasma membrane
True
Hypothetically , What would be the most immediate effect of doubling the number of Na+ leakage channels in the plasma membrane?
The resting membrane potential would become less negative (more positive).
Suppose a drug is developed that blocks K+ leakage channels. The drug prevents ions from passing through those channels. If this drug was applied to a neuron, what would be the most immediate effect on that neuron?
The resting membrane potential would become less negative (more positive).
Select the correct statement regarding synapses
The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
Which of the following is not true of greased potentials
They increase amplitude as they move form the stimulus point
Why does injection of local anesthetic into finger still cause loss of sensation of touch from finger?
Touch stimulation of this sensory receptor will open mechanically gated ion channels, but action potentials are still not initiated because propagation to an action potential requires opening of voltage-gate Na+ channels
A postsynaptic potential is a graded potential that is the result of a neurotransmitter released into the synapse between two neurons.
True
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
Axon diameter and degree of myelination determine nerve impulse conduction velocity.
True
During depolarization, the inside of the neuron's membrane becomes less negative.
True
Enkephalins and endorphins are peptides that act like morphine.
True
In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.
True
Large-diameter nerve fibers conduct impulses much faster than small-diameter fibers.
True
What changes in a neuron is being measured in the graph?
Voltage measured across the axon membrane at a specific point as an action potential travels past
When an action potential arrives at the end of axon Terminal, a series of events take place that result in release of neurotransmitter from the presynaptic axon.Primary stimulus for vehicles to move towards the cell membrane and eventually release their contents.
Voltage-gated membrane channels open, and Ca+2 Enters the cytoplasm, increasing intercellular positive charge
At which point of the illustrated potential are the most gated Na+ channels open?
When membrane potential reaches threshold and soon close when temporarily inactivated during depolarization phase "C"
Satellite cells
Wraps and insulates soma of neurons within ganglia in PSN
What type of channel on the postsynaptic membrane binds neurotransmitter?
a chemically gated channel
What type of stimulus is required for an action potential to be generated?
a threshold level depolarization
The neuron cannot respond to a second stimulus, no matter how strong.
absolute refractory period
Depolarization caused by
action potential results in opening of voltage-gated Ca2+ channels in membrane axonal terminus
Also called a nerve impulse transmitted by axons.
action potentials
Which of the following correctly describes a graded potential?
amplitude of various sizes
Cold sores on the skin of the mouth occur when herpes simplex viruses that are dormant in neural ganglia become active and travel to the skin of the mouth. Which of the following is the mechanism by which these viruses travel from the ganglia (located within the head) to the skin of the mouth?
anterograde axonal transports
Which neuroglia are the most abundant and versatile of the glial cells?
astrocytes
Which of the following is the conducting region of the neuron
axon
Which part of the neuron is responsible for generating a nerve impulse?
axon
If the membrane of a postsynaptic dendrite is setting up a graded potential, what must have happened after neurotransmitter was released by the presynaptic terminal?
bound at postsynaptic receptors to open postsynaptic ion channels.
What part of the nervous system performs information processing and integration?
central nervous system
Binding of a neurotransmitter to its receptors opens __________ channels on the __________ membrane.
chemically gated; postsynaptic
The interior of the cell becomes less negative due to an influx of sodium ions
depolarization
What is the role of acetylcholinesterase?
destroy ACh a brief period after its release by the axon endings
What does the central nervous system use to determine the strength of a stimulus
frequency of action potentials
When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________.
generator potential
An inhibitory postsynaptic potential (IPSP) is associated with ________.
hyperpolarization
When neurotransmitter molecules bind to receptors in plasma membrane of receiving neuron,
ion channels in plasma membrane of receiving neuron open.
ependymal cells
line central cavities of CNS.
Which of the following types of glial cells monitors the health of neurons, and can transform into a special type of macrophage to protect endangered neurons
microgliae
Which of the following would increase the membrane permeability to K+
more K+ leakage channels
Astrocytes
most abundant CNS neuroglia
Saltatory conduction is made possible by ________.
myelin sheath, schwann cells
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________.
negatively charged and contains less sodium
Neurons are also called
nerve cells
Which of the following are bundles of neurofilaments that are important in maintaining the shape and integrity of neurons
neurofibrils
A postsynaptic cell can be a neuron, a muscle cell, or a secretory cell. What is an example of a presynaptic cell?
neuron
A molecule that carries information across a synaptic cleft is a
neurotransmitter
The substance released at axon terminals to propagate a nervous impulse is called a(n) ________.
neurotransmitter
Which of the following is not a chemical class of neurotransmitter
nucleic acid
In multiple sclerosis, the cells that are the target of an autoimmune attack are the
oligodendrocytes
Which best represents synaptic transmission?
presynaptic axon to synapse to dendrite or postsynaptic cell body
If a signal from a sending neuron makes the receiving neuron more negative inside,
receiving neuron is less likely to generate an action potential.
An exceptionally strong stimulus can trigger a response.
relative refractory period
The specific period during which potassium ions diffuse out of the neuron due to a change in membrane permeability.
repolarization
In addition to diffusion, what are two other mechanisms that terminate neurotransmitter activity?
reuptake and degradation
Which of the following describes the excitatory postsynaptic potential
short distance depolarization
Which of the following best characterizes depolarization
small consecutive steps of Na+ penetration into the axon along its length
Which of the following allows us to consciously control our skeletal muscles?
somatic nervous system
An impulse from one nerve cell is communicated to another nerve cell via the ________.
synapse
The small space between the sending neuron and the receiving neuron is the
synaptic cleft
Imagine you changed the concentration of K+ outside a neuron such that the resting membrane potential changed to -80 mV (from the normal resting value of -70 mV). What have you changed?
the electrical gradient for K+ and the concentration gradient for K+
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________.
the impulse would spread bidirectionally
A second nerve impulse cannot be generated until ________.
the membrane potential has been reestablished
What is the electrochemical gradient of an ion
the sum of the electrical and chemical gradients for that ion
When calcium ions enter the synaptic terminal,
they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.
An action potential releases neurotransmitter from a neuron by opening which of the following channels?
voltage-gated Ca2+ channels
Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?
voltage-gated channel