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Motor Control Neural Transmission
Motor Control Neural Transmission
121
Anatomy
Graduate
09/29/2014

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Term
Are the dendrites of sensory neurons short or long?
Definition
long
Term
are the axons of sensory neurons short or long?
Definition
short
Term
where are sensory nerve cell bodies housed?
Definition
dorsal root ganglion
Term
are the dendrites of motor neurons short or long?
Definition
short
Term
are the axons of motor neurons short or long?
Definition
long
Term
where and on what do motor neurons synapse
Definition
motor neurons send information down spinal cord, synapse on alpha motor neuron
Term
most neurons are what kind of neuron?
Definition
interneuron
Term
what is the function of astrocytes?
Definition
secretion and absorption of neural transmitters, maintenance of the blood-brain barrier
Term
astrocytes are a subtype of what type of cell?
Definition
gial cells
Term
where do astrocytes like to be?
Definition
around synapses made by neurons
Term
after coming in through the dendrites, where does information in a neuron go to be integrated?
Definition
axon hillock
Term
once summation of information gets to a certain point within the cell, what will happen
Definition
it will generate an action potential that can go down the axon and to the terminal synapses
Term
what is used to transfer electrical signals through neurons?
Definition
chemicals in the body
Term
what are some important positive ions in the nervous system
Definition
sodium, potassium, calcium
Term
what is an important negative ion in the nervous system?
Definition
chloride
Term
do proteins have + or - charge?
Definition
different proteins are +, some are -
Term
describe the nerve cell membrane in one word
Definition
semi-permeable
Term
what is the resting potential of the cell?
Definition
-65 mV
Term
are the neuron's membrane's ion channels open or closed at rest?
Definition
closed at rest
Term
what is the major ion inside the neuron at rest?
Definition
potassium
Term
what is the major ion outside the cell at rest?
Definition
sodium
Term
what is inside the cell that gives it a negative resting charge?
Definition
negatively charged proteins
Term
what maintains the charge imbalance at rest?
Definition
sodium potassium pump that actively transport ions against their concentration gradients
Term
what do we call the places where ions are passed across the cell membrane?
Definition
gates or channels
Term
what kinds of stimuli will cause the membrane potentials to change
Definition
chemical or physical stimuli
Term
what happens when the membrane ptoentials change?
Definition
the sodium and potassium channels each open, allowign sodium to enter and potassium to exit
Term
what happens as a result of the change in concentrations as potassium exits the cell and sodium enters the cell following a stimulus to the neuron?
Definition
the change in concentration gradient produces a local passive current that is propagated along the membrane
Term
what causes the local passive current caused by the change in concentration gradient to decay?
Definition
distance and time
Term
what does it mean if you are farther away in the dendrite from the axon hillock?
Definition
you might have less effect on the transmission of an impulse
Term
how does sodium entering the neuron change its potential?
Definition
sodium entering the cell makes the membrane potential more positive
Term
what membrane potential must be reached to trigger an action potential?
Definition
-50 mV
Term
what is the response to an action potential?
Definition
all soidum channels open and rapid depolarization occurs as soidum enters the cell
Term
what happens when the membrane potential reaches + 50 mV?
Definition
sodium channels close and potassium channels open so that potassium can exit the cell and restore resting membrane potential
Term
How is the neuron restored to its original distribution of ions?
Definition
sodium ions are pumped out of the cell and potassium ions are pumped into the cell
Term
what is the general path of information transmission in the CNS?
Definition
synapse on dendrite -> local depolarization goes through cell body -> goes into axon hillock -> travels down axon -> into terminal synapse -> into post synaptic membrane of the next target cell
Term
is the dendrite presynaptic or postsynaptic?
Definition
postsynaptic
Term
will an excitatory post synaptic potential depolarie or polarize the cell?
Definition
EPSP deploarizes the cell
Term
will an inhibitor post synaptic potential depolarize or polarize the cell?
Definition
IPSP polarizes the cell
Term
what if a neuron receives both EPSPs and IPSPs?
Definition
they sum
Term
can an axon from a neuron give both IPSPs and EPSPs
Definition
no, all synapses from one axon is either all EPSP or all IPSP
Term
what will happen if you can depolarize the cell to -55 mV?
Definition
you can generate an action potential
Term
what is the mechanism for an IPSP?
Definition
moving potassium out of the cell to make it more negative
Term
what ions can be added to the neuron to hyperpolarize it
Definition
chloride
Term
how many synapses can you have on each neuron?
Definition
many
Term
what is electrotonus?
Definition
the passive spread of current inside a neuron
Term
what is neural integration
Definition
ability of neurons to process info, store/recall it, and make decisions. Example: you have knee pain, your CNS senses the pain, your CNS reduces the amount of work that you can do
Term
where in the neuron do synaptic potentials sum?
Definition
axon hillock
Term
if you are a distal dendrite far from the axon hillock, are the synapses you get necessarily going to make an action potential?
Definition
your synapses will have to travel farther to get to axon hillock. The EPSPs all have to sum to -55mV at the axon hillock to make an action potential
Term
describe the temporal strategy for summation of EPSP and IPSP
Definition
increase the frequency of signal
Term
describe the spatial strategy for summation of EPSP and IPSP?
Definition
increase the number of sources
Term
what happens when you stretch a muscle?
Definition
the muscle spindle excites its own alpha motor neuron and makes it want to contract
Term
how does increasing frequency increase the likelihood of an excitatory response?
Definition
before the EPSP can decay, the nexxt stimulus arrives. This continues until we reach threshold
Term
what happens at the synapse when the action potential arrives?
Definition
local depolarization causes clacium channels ot open and to let in clacium
Term
when calcium enters the presynaptic nere ending, what happens?
Definition
clacium causes vesicles filled with neurotransmitter to migrate towards the presyaptic membrane and bind with it
Term
what happens once the neurotransmitter binds with the presynaptic membrane?
Definition
the neurotransmitter is released into the synaptic cleft
Term
what happens when the neurotransmitter is released intot he synaptic cleft?
Definition
it diffuses and binds with receptors and receptor cahnenel membranes
Term
if neurotransmitters were continually in the synaptic cleft, what would happen?
Definition
the postsynaptic channels would always be stimulated so that the membrane potential couldn't restabilize
Term
what are the 3 ways that neurotransmitters are deactivated?
Definition
degradation, reuptake, autoreceptors
Term
what is degradation of a neurotransmitter/
Definition
enzymes located int eh synaptic cleft break down the neurotransmitter so that it has no effect on the receptor/receptor channel of the postsynaptic cells
Term
what is neurotransmitter reuptake?
Definition
allowing the neurotransmitter to reenter the presynaptic cell through membrane channels for reuse
Term
what are autoreceptors
Definition
receptors for specific neurotransmitters that are located on the presynaptic membrane and respond to neurotransmitter release by decreasing further release of the neurotransmitter
Term
what is long term potentiation
Definition
increase sensitivity of senapses so that a constant level of presynaptic stimulation is converted into a larger postsynaptic output
Term
how long can longterm potentiation last?
Definition
for weeks
Term
what is LTP associated with?
Definition
learning
Term
give an example of LTP
Definition
how a trained person will sweat faster during exercise becaause their synapses are sensitive so that a stimulation will more quickly produce a larger postsynaptic output
Term
what is the role of neurotransmitters?
Definition
to inhibit or excite the postsynaptic cell by changing its membrane potential
Term
what determines whether a neurotransmitter is excitatory or inhibitory?
Definition
the neurotransmitter + its receptor site
Term
what is the most common neurotransmitter in the brain?
Definition
glutamate
Term
is glutamate excitatory or inhibitory
Definition
excitatory
Term
what is aspartate
Definition
an excitatory neurotransmitter found in the spinal cord
Term
what is dopamine
Definition
a neurotransmitter that can be either excitatory or inhibitory
Term
is dopamine more commonly excitatory or inhibitory
Definition
usually excitatory
Term
what is the main focus of the locus coeroleous
Definition
automatic movements
Term
what is the main neurotransmitter of the locus coeroleous
Definition
norepinephrine
Term
what is the primary neurotransmitter at the neuromuscular junction?
Definition
acetylcholine
Term
is acetylcholine excitatory or inhibitory
Definition
exictatory
Term
is serotonin excitatory or inhibitory
Definition
excitatory
Term
is norepinephrine excitatory or inhibitory?
Definition
excitatory
Term
what is the extrapyramidal pathway
Definition
projections between the cortex and striatum
Term
what functions is the basal ganglia associated with?
Definition
sensation and movement
Term
what functions is the forebrain associated with?
Definition
cognition, reward, emotional behavior
Term
what functions is the tubero-infundibular system concerned with?
Definition
control of the hypothalamic-pituitary endocrine system
Term
what neurotransmitter affects the basal ganglia?
Definition
dopamine
Term
what neurotransmitter affects the mesolimbic forebrain/
Definition
dopamine
Term
what neurotransmitter affects the tubero-infundibular system?
Definition
dopamine
Term
what neurotransmitter affects the locus coeroleus?
Definition
norepinephrine
Term
what is the function of the locus coeroleus?
Definition
automatic movements: fight or flight
Term
what neurotransmitter affects the raphe nuclei?
Definition
serotonin
Term
to what other parts of the brain does the locus coeruleus connect?
Definition
many other areas, particularly areas that bring in and process information, especially sensory information
Term
what does the locus coeroleus secrete?
Definition
norepinephrine
Term
what is the pacemaker of the brain?
Definition
locus coeruleus
Term
what does the locus coeroleus do in times of stress?
Definition
increases arousal and vigilance and modulates action of the autonomic nervous system
Term
for what functions is the locus coeruleus critical?
Definition
nuermous functions including stress, attention, emotions, motivtion, decision making, or learning and memory
Term
what is the major inhibitory neurotransmitter of the brain?
Definition
GABA
Term
what happens when you take drugs that block GABAa receptors?
Definition
you get seizures
Term
what happens when you take drugs that activate GABAa receptors?
Definition
seizures are controlled
Term
blocking GABA b receptors can help with what?
Definition
depression
Term
what is glycine?
Definition
a major inhibitory neurotransmitter in the spinal cord
Term
where do we see GABAergic inhibition?
Definition
throughout the CNS
Term
about how much of the inhibitory synapses in the brain are GABA mediated?
Definition
50.00000%
Term
what types of simple circuits regulate how and if signals are transmitted?
Definition
post synaptic excitation, disfacilitation, postsynaptic inhibition, disinhibition, presyanptic inhibition
Term
what is another name for presynaptic inhibition
Definition
axo-axonal inhibition
Term
what is post-synaptic inhibition
Definition
that is the regular depolarization of a cell from an excitatory synapse. It creates an excitatory post synaptic potential
Term
what is disfacilitation
Definition
when an inhibitory cell prevents an excitatory cell from exciting the target cell
Term
what is post synaptic inhibition
Definition
using an inhibitory cell on the target cell to inhibit the target cell
Term
what is disinhibition
Definition
using an inhibitory cell to inhibit the inhibitory cell on the target cell so that the inhibitory cell on the target cell is less likely to fully inhibit the target cell
Term
what is an example of a post synaptic exicitation
Definition
a muscle spindle will activate its own alpha motor neuron through post synaptic excitation.
Term
what is an exaple of post synaptic inhibition
Definition
a muscle spindle will deactivate the alpha motor neuron of an antagonist muscle by using an inhibitory interneuron to create post synaptic inhibition on the antagonist muscle
Term
what is an example of disfacilitation
Definition
in the direct pathway in the basal ganglia, the caudate and putamen inhibit the globus pallidus internal segment to keep it from inhibiting the thalamus
Term
what is presynaptic inhibition/axo-axonal synapse?
Definition
Neuron A synapses on Neuron B near Neuron B's terminal ending. This partially depolarizes the terminal end of Neuron B, relasing some of Neuron B's transmitter. The result is decreased available neurotransmitter, reducing the effect of a real action potential when it comes along
Term
what does PAD stand for
Definition
primary afferent depolarization
Term
what is primary afferent depolarization
Definition
the CNS sends excitatory connections down the psinal cord to the terminal ending to reduce the excitatory effects of the primary afferents
Term
are there any inhibitory afferents?
Definition
no. all primary afferents try to have a positive efefct that make semothing happen
Term
what are the primary afferents
Definition
touch, smell, hearing, pain, sensory
Term
what is the effect of presynaptic inhibition on the target cell?
Definition
decreased effect because there is not as much excitatory neurotransmitter
Term
what does MEPP stand for?
Definition
minature end plate potentials
Term
what is a miniature end plate potential?
Definition
A small miniature excitatory post synaptic potential in which the terminal ending is partially depolarized, resleasing small neurotransmitter packages
Term
describe an example of presynaptic inhibition
Definition
to reduce the incoming informaiton from primary afferents,t he CNS sends excitatory informatino down the psinal cord to the terminal ending to create miniature end plate potentials at the posts ynaptic membrane, reducing the available neurotransmitter and therefore reducing the effect of an action potential.
Term
what is surround or recurrent inhibhition?
Definition
when a recurrent collateral synapses with a nearby inhibitory neuron to reduce its activity and to acceentuate an excited area around an inhibitory area to sharpen contrast
Term
what is the purpose of surround or recurrent inhibition?
Definition
to sharpen tuning for finer localization by accentuating the excited area
Term
where is surround inhibition important?
Definition
retina, sensory cortex for 2 point discrimination
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