Nervous Tissue Quiz 2
In the soduim-potassium pump,
potassium enters and sodium leaves the cell
In a neuron, where does an action potential first appear after the neuron has been adequately stimulated on a dendrite?
the axon hillock
In a neuron, where does an action potential first appear after the neuron has been completely stimulated on a dendrite?
the axon hillock
The membrane potential returns to the resting state due to ________.
the diffusion of ions through leak channels
All of the following are true of action potentials except: ______________.
they travel more slowly on myelinated fibers
What type of ion channel opens in response to an action potential arriving at the axon terminal?
voltage-gated calcium
Which of the following is characteristics of an action potential?
voltage-gated ion channels
One of the following represents spatial summation. The other choices could represent either spatial or temporal summation. Which one only represents spatial summation?
(+5 mV) + (+10 mV)
A neuron is receiving two simultaneous inputs, one of which is -10 mV. If the cells RMP is -70 mV and threshold is -60 mV, what is the minimum value of the other input that would cause the neuron to generate an action potential?
+20 mV
A nerve fiber has a RMP of -80 mV and a threshold potential of -60 mV. Which of the following is most likely to generate an action potential?
-20 mV IPSP and +5 mV EPSP
______ studies seek to identify the patterns, causes, and control of disorders in groups of people.
Epidemiological
Which of the following is a graded, non-propagated, hyperpolarization of a neuron plasma membrane?
IPSP
Which of the following is grated, non-propagted, hyperpolarization of a neuron plasma membrane ?
IPSP
The hyperpolarization phase of AP is caused by too much _____ leaving the cell.
K+
The hyperpolarization phase of the action potential is caused by too much ____ leaving the cell.
K+
Which of the following enters the postsynaptic terminal and initiates an EPSP at an electrochemical synapse?
Na+
During action potential of a neuron
Na+ moves into the call and then K+ moves out of the cell
During an action potential of a neuron
Na+ moves into the cell and then K+ moves out of the cell
Which of the following is NOT a characteristic of neurons?
Neurons are relatively small, simple-structured cells
Which of the following statements is true?
Neurotransmitter molecules are stored in vesicles located in the axon terminal region of the presynaptic cell.
Which of the following statements concerning inhibitory synapses (IPSPs) is correct?
The postsynaptic membrane becomes more permeable to potassium and/or chloride
Which of the following statements concerning inhibitory synapses (ISPSs) is correct?
The postsynaptic membrane becomes more permeable to potassium and/or chloride
Which type of ion channel opens when a chemical binds to it?
chemically gated (ligand-gated) channel
Saltatory conduction refers to:
conduction of a nerve impulse by a myelinated axon
The most probable site on a neuron where incoming information is received is the _____?
dendrite
A change in membrane potential from -70 mV to -40 mV would be termed ______.
depolarization
Generation of an action potential can be inhibited by all the following except: ________.
depolarization
A graded, non-propagated potential the increased sodium conductance into a postsynaptic cell which is not skeletal muscle is a(n) _____.
excitatory postsynaptic potential
The speed of a nerve impulse is determined by all of the following except the ______.
intensity of a stimulus
What is the direction of the driving force(s) for the movement of potassium ions when a nerve cell is at rest?
inward electrical gradient and outward chemical gradient
Acetylcholinesterase:
is an enzyme that cleaves acetyl from choline
The normal AP exhibited by a single neuron:
is conducted without decrement (decreased velocity/amplitude)
Which of the following factors is associated with increased conduction velocity in an axon?
large diameter
In which of the following would the velocity of nerve impulse conduction be the greatest?
large diameter myelinated fibers
Which of the following membrane ion channels in the neuron are always open?
leakage channels
With respect to the neuron, the sodium-potassium pump:
maintains the outward potassium diffusion gradient
Depolarization of a dendrite results in current flow between the dendrite and the ____ resulting in propagation of a nerve impulse
neurosoma
Synaptic transmission is made possible by ____.
neurotransmitters
What is the direction of the driving forces for the movement of sodium ions oat the peak of the action potential spike?
outward electrical gradient and inward chemical gradient
At rest, a cell will have more _____ ions in the cytoplasm than outside the cell
potassium
The movement of which ion out of the cell through leakage channels establishes the negative membrane potential?
potassium
IPSPs cause the postsynaptic membrane to become more preamble to ______.
potassium exiting
Neurotransmitters are removed from the synaptic cleft by all of the following except: _______.
presynaptic inhibition
Neurotransmitters are removed from the synaptic cleft by all of the following except: _____l
presynaptic inhibition
The sodium-potassium ion pump will _____.
pump three sodium ions out of the cell for every two ions of potassium it brings into the cell
The sodium-potassium pump will ______.
pump three sodium ions out of the cell for every two ions of potassium it brings into the cell
The period of excitability during which a greater than normal strength of stimulus is required to elicit a cell response is termed the ____.
relative refractory period
During which phase of an action potential are voltage-gated K+ channels open, while voltage-gated Na+ channels are closed?
repolarization
Which part of the action potential occurs when the voltage-gated Na+ channels are inactivating and voltage-gated K+ channels open?
repolarization
You would expect a neuron that depolarizes to -65 mV would __________.
return to resting membrane potential without generating an action potential
Which of the following characteristic is NOT associated with a myelinated nerve fiber?
slow conduction of nerve impulses
During the repolarization phase of the action potential, there is a decrease in the membrane permeability to which ion?
sodium
When the effects of EPSPs occurring at different synapses combine to generate an action potential, the process is called:
spatial summation
Somatic integration involving the additive effect of 2 or more EPSP's produced in rapid succession at on synapse defines:
temporal summation
The resting membrane potential depends on each item below, EXCEPT:
the greater permeability of the membrane to anions rather that cations
APs are normally generated at the beginning of the axon because:
the membrane in this area has a very low electrical resistance
The resting membrane potential of a neuron is dependent on:
the presence of non-diffusible anions inside the cell
A membrane maintains its resting potential mainly due to ____.
the sodium-potassium pump
A membrane maintains its resting potential mainly due to _____.
the sodium-potassium pump
Relative to the transmission of a nerve impulse, the membrane potential at which the membrane suddenly becomes highly permeable to Na+ is the _______
threshold potential
Which of the following is NOT a function of the myelin sheath?
to recapture and recycle released neurotransmitters
Studies on medication, new medical devices, or a new approach to a surgery are all types of _______________________ research.
treatment
Information is coded in the nervous system by:
varying the frequency of the APs
Which of the following membrane ion channels open and close in response to changes in the membrane potential?
voltage-gated channels
Which of the following is a characteristic of an action potential?
voltage-gated ion channels
Which of the following is characteristic of an action potential?
voltage-gated ion channels
IPSPs never generate APs
True
Integration of incoming signals is a function of which part of the neuron?
axon hillock
Which of the following are the main receptive or input regions found in neurons?
dendrites
During transmission at an electrochemical synapse, neurotransmitter molecules are released from the presynaptic neuron by:
exocytosis
According to the "all-or-none" law:
for a given nerve fiber, the amplitude of the action potential does not vary with the strength of the stimulus
In a neuron, a membrane potential of -90 mV is considered _____.
hyperpolarized
The speed of a nerve impulse is determined by all of the following except the ________.
intensity of a stimulus
Which of the following factors is associated with increased conduction velocity in an action?
large diameter
An action potential is a phenomenon that either happens completely or doesn't happen at all.
True
Dendrites and axons are both armlike processes that extend from neuron cell bodies.
True
The speed of impulse conduction is faster in myelinated neurons with relatively large diameters than in unmyelinated nerve fibers with small diameters.
True
What type of ion channel opens in response to an action potential arriving at the axon terminal?
Voltage-gated calcium
The time interval during which no stimulus can elicit an action potential in a nerve fiber is call ______.
absolute refractory period
A non-grated, propgated potential that follows the "all-or-none" law is a(n) ________.
action potential
Which of the following does not decay with distance?
action potential
Which of the following electrical events occurs when a certain threshold is reached?
action potential
Which type of potential does NOT decay with distance?
action potential
According to the "all-or-none" law:
action potential amplitude for a given neuron is constant
Synaptic transmission can be blocked by:
all are ways of blocking synaptic transmission
The establishment and maintenance of a cell's resting membrane potential is dependent on:
all listed are correct
The principal cause of depolarization of a nerve fiber when threshold is reached is
an increase in the inward conductance of Na+
Depolarization of a dendrite results in current flow between the dendrite and the _____ resulting in propagation of a nerve impulse.
axon hillock
Depolarization of a dendrite results in current flow between the dendrite and the ______ resulting in propagation of a nerve impulse.
axon hillock
The presynaptic neuron releases neurotransmitters in response to an influx of _____ ions.
calcium
Which of the following statements is incorrect concerning a nerve impulse?
All of the statements are true
Which of the following statements best describes the resting membrane state in the neuron?
All of the voltage-gated Na+ and K+ channels are closed
Which of the following statements is true?
All the other statements are false
Synaptic vesicles are inducted to migrate toward and blend with the presynaptic membrane and then to release neurotransmitter into synaptic cleft as a result of an increase in the concentration of free ____ in the presynaptic terminal.
Ca2+
Which of the following is NOT true of neurons?
They are the most abundant cells of nervous tissue
Which of the following is FALSE regarding chemical synapses?
They transmit nerve impulses directly from one neuron to another
