NERVOUS SYSTEM
Ion movement across the postsynaptic membrane as a result of neurotransmitter binding
may depolarize or hyperpolarize the postsynaptic neuron
Which statement is CORRECT?
Depolarization refers to the process where the neuronal membrane becomes more positive
Which statement is CORRECT?
Hyperpolarization results in a membrane potential that is more negative than the resting membrane potential.
Which postsynaptic potential is more negative than the resting membrane potential
IPSP
Excitable cells are most permeable to which of the following ions?
K+
The part of a neuron that conducts impulses away from its cell body is called a(n)
axon
What gradient(s) would tend to move Na+ into the cell?
both electrical and concentration gradient
an increase in what ion at the axon terminal region of the presynaptic neuron results in a neurotransmitter release
calcium
A neurotransmitter is the chemical signal that opens voltage-gated ion channels
false
Ion channels allow for the random movement of all ions across the neuronal cell membrane.
false
The rising phase of the action potential ends when the permeability of K+ decreases.
false
a normal synaptic potential is higher in amplitude than an action synaptic potential
false
A cell that received ten EPSPs and two IPSPs to the axon hillock would most likely
generate an action potential
Nongated (passive) channels are located?
in the cell membrane of the entire neuron
The sheath of Schwann cells that aids in regeneration is also called the
neurolemma
Substances that bind to chemically gated channels of neurons are known as
neurotransmitters
chemically gated channels are located?
on dendrites and the cell body
voltage gated channels are located?
on the axon, hillock, all along the unmyelinated axons, the nodes of ranvier, and in the myelinated axons.
Depolarization is caused by the movement of what ion in what direction?
potassium; out of the cell
Which event happens immediately after a neurotransmitter binds to its postsynaptic membrane receptor?
chemically gated ion channels open
When a neuron is at rest, voltage gated channels are
closed
Which of the following would increase membrane permeability to K+?
closing voltage-gated K+ channels
Which of the following describes the nervous system's integrative function?
senses change, processes information, and makes a decision
Open voltage-gated sodium channels result in
sodium moving into the cell
Increasing the number of synapses from different neurons would cause which type of summation?
spatial summation
which event occurs immediately after extracellular calcium enters the axon terminal region
synaptic vesicles fuse with the membrane
Increasing the number of action potentials on a presynaptic axon in a given period of time would cause what type of summation?
temporal summation
Inhibitory synapses have the maximum effect if they are located on what part of the neuron?
the cell body, near the axon hillock
if an inhibitory postsynaptic potential occurs at the same time as an excitatory postsynaptic potential
the magnitude of the excitatory postsynaptic potential will be reduced and may be cancelled out all together
which statement is correct
the mechanism by which neurotransmitters are returned to the terminal is specific to each neurotransmitter
what happens to synaptic potentials as they travel away form the synapse
they weaken
Chemically gated ion channel opens when a specific neurotransmitter binds to it.
true
During an action potential, voltage-gated sodium channels open rapidly, then inactivate, and finally reset to the closed state.
true
It takes many EPSP to depolarize a neuron threshold
true
Membrane proteins known as ion channels allow ions to flow across the neuronal cell membrane.
true
Synapses located a great distance from the axon hillock will be less likely to trigger an action potential
true
Threshold refers to the voltage that opens the voltage-gated channels located in the axon hillock region of the neuron
true
Voltage-gated potassium channels open when the action potential reaches its peak
true
When and only when a neuron reaches threshold, a positive feedback loop for opening sodium channels is established?
true
the job of a neuron is to select a single output from competing inputs
true
At the end of the depolarization phase, what voltage-gated channels open to help restore the resting membrane potential?
voltage gated K+ channels
Which potentials decay as they move along the neuronal membrane?
Both EPSPs and IPSPs
When the neurotransmitter binds to a receptor located on the postsynaptic membrane
NOT all answers correct!!!
one of the roles of a convergent neural pathway is
NOT decrease the need for complex neural pathways!!! NOT enhanced release of neurotransmitter NOT TO INCREASE CELLULAR INTEGRATION
As the axon hillock depolarizes
Na+ moves down its electrochemical gradient
This change is caused by the opening of ___ then ____ voltage-gated channels
Na+ then K+
Voltage-gated channels
Responsible for generation and propagation of the outgoing signal, the action potential
Chemically gated channels
Responsible for incoming signals, the synaptic potentials
Passive (nongated) channels
Responsible for the resting membrane potential of the neuron
Which of the following describes the nervous system's sensory function?
Senses changes in the internal and external environment.
which statement is incorrect
a synapse near the axon hillock has less influence on the generation of an action potential than one farther away
Rapid firing of presynaptic action potentials will result in
all answers are correct
The rising phase of an action potential ends when
all answers are correct
When an action potential reaches the end terminal region of a presynaptic neuron
all answers are correct
The rising phase of an action potential ends when
all of the above
When threshold is reached
all statements are correct
As the axon hillock depolarizes, Voltage-gated Na+ channels open and Na+ moves (into or out of) __________ the cell causing further (depolarization or repolarization)
into; depolarization
potentiation/facilitation of a synaptic potential is caused by
keeping the postsynaptic membrane potential slightly depolarized
A positive ion moving into a cell would result in a membrane potential that
less negative