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
most common tumor in adults
Astrocytoma
Tinnitus, facial weakness, and vertigo neoplasm would affect
Schwannoma (peripheral nerves )
Rabies ptx have
negri bodies
Electrical synapses occur
gap junctions
At presynaptic neuron to NMJ, The arrival of a nerve signal at the axon terminal
opens
voltage-gated calcium channels.
Amino acid and monoamine neurotransmitters are
similarly reabsorbed, then broken down within the axon
terminal by an enzyme called
monoamine oxidase (MAO)
NE, other monoamines, and neuropeptides
act through second-messenger systems
cyclic AMP (cAMP).
Na+ flowing into the cell and neutralizing some of the
negative charge on the inside of the membrane is what type of potential
Excitatory postsynaptic potential (EPSP)
A neurotransmitter hyperpolarizes the
postsynaptic cell and makes it more negative
than the RMP. This potential is ______
Inhibitory postsynaptic potential (IPSP)
Opening of Cl- channel causing influx into the cell
when a single synapse generates EPSPs so quickly
that each is generated before the previous one
fades.
Temporal summation
when
EPSPs from several synapses add up to
threshold at the axon hillock.
Spatial summation.
excitatory brain neurotransmitters that
produce EPSPs.
Glutamate and aspartate
inhibitory neurotransmitters that produce IPSPs and
Glycine and GABA
ACh excites skeletal muscle but inhibits cardiac muscle because of different
types of ACh receptors.
Muscuranic- cardiac muscles
Nicotinic - skeletal muscle ad neurons
Location of glycine
brain, spinal cord and retina
location of GABA
thalamus, occipital lobes of cerebrum, cerebellum, hypothalamus, retina
The neurotransmitter involved in learning and memory (75% of EXCITATORY SYNAPSES ) is _______
located in the
Glutamate
cerebral cortex and brain stem
Neurotransmitter for dreaming, waking, mood, excites cardiomyocytes is ______ & located in the
Norepinephrine
hypothalamus, brain stem, cerebellum and spinal cord,cerebral cortex
Epinephrine unlike norepinphrine acts on
Adrenal medulla
neurotransmitter high in substantia nigra of midbrain, hypothalamus, limbic system, cerebellum, spinal cord, retina
dopamine (controls mood and skeletal muscles )
neurotransmitter secreted by platelets, and intestinal cells involved in sleepiness, alertness, thermoregulation and mood
serotonin
neuropeptide that mediates pain transmission
Substance p
Neuropeptides that act as analgesics by inhibiting substance p, inhibit intestinal mobility and modulate immune response
Enkephalins
