NEURAL SIGNALING Flashcards
a difference in the concentration of charged
particles between one point and another.
Electric potential
The charge difference across the plasma
membrane is called the
resting membrane potential
Ion that has the greatest influence on resting membrane potential
Potassium (bcos the plasma membrane is more permeable to K+)
At equilibrium _____ is about 40 times as
concentrated in the ICF as in the ECF.
Potassium
At equilibrium ______ is about 12 times as concentrated in the
ECF as in the ICF.
Sodium
The chemical (ligand) binds to receptors on the neuron. This opens
ligand-gated sodium channels
that allow Na+ to flow into the cell.
case in which the voltage shifts to a less negative value is called
depolarisation
short-range change in voltage produced by gated channels on soma and dendrites
Local potential
the site of generation of action potentials in a neuron.
Axon hillock
rapid up-and-down shift in voltage produced by voltage gated channels on the trigger zone and axon is
Action potential
Resting membrane potential is maintained by
leak channels and Na+/K+ pump
Voltage gated Na+ channels is blocked by_____ which extracellularly bind to the channel
Tetradoxin (TTX) In puffer fish
Voltage gated Na+ channels is blocked by_____ which Intracellularly bind to the channel
Lidocaine ( local anesthetic)
Voltage gated K+ channels is blocked by_____ which extracellularly bind to the channel
4-aminopyridine
Tetraethylammonium
For anything more to happen, this local potential must rise to a critical voltage called the threshold
-55mv
Action potentials are non decremental means
They don’t get weaker with distance.
Drug X applied to a nerve axon decreases the duration of the action potential without
affecting the resting potential or peak amplitude of the action potential. Which of the
following is the most likely mechanism of action of Drug X?
(A) Block of voltage-dependent Na+ permeability
(B) Decrease in the rate of Na+ inactivation
(C) Decrease in voltage-dependent Na+ permeability
(D) Increase in the rate of voltage-dependent changes in K+ permeability
(E) Inhibition of the Na+–K+ pump
(D) Increase in the rate of voltage-dependent changes in K+ permeability
Which of the following types of ion channels is responsible for
generating graded potentials in response to neurotransmitter
binding?
a) Voltage-gated ion channels
b) Ligand-gated ion channels
c) Leak channels
d) Mechanically gated ion channels
b) Ligand-gated ion channels
Inhibitory postsynaptic potentials (IPSPs):
a) Depolarize the postsynaptic membrane
b) Increase the likelihood of an action potential
c) Hyperpolarize the postsynaptic membrane
d) Enhance synaptic transmission
c) Hyperpolarize the postsynaptic membrane
Which of the following ions plays a key role in the depolarization
phase of an action potential?
a) Sodium (Na+)
b) Potassium (K+)
c) Calcium (Ca2+)
d) Chloride (Cl-)
a) Sodium (Na+)
Which of the following events occurs directly after the depolarization phase
of an action potential?
a) Repolarization
b) Hyperpolarization
c) Refractory period
d) Synaptic transmission
a) Repolarization
young woman with vision problems indicate
multiple sclerosis
damage to axons distal to injured nerve
wullerian degeneration
peripheral nerve regenerate at the rate of
3mm/day
