NEUROSCIENCE EXAM 1 QUESTIONS
WITH COMPLETE ANSWERS
EPSP Summation - Answer-The simplest form of synaptic integration in the CNS.
There are two types: spatial and temporal
Spatial Summation - Answer-addition of EPSPs generated simultaneously at many
different synapses on a dendrite
Temporal Summation - Answer-addition of EPSPs generated at the same synapses
as they occur in rapid succession (1/15 m sec apart)
Length Constant (λ) - Answer-Distance from the synapse where the depolarization is
37% of that at the origin
Internal resistance - Answer-The resistance of current flowing longitudinally down the
dendrite. It depends only on the diameter of the dendrite & electrical properties of the
cytoplasm (constant)
Higher = Lower λ
Membrane resistance - Answer-The resistance of current flowing across the
membrane. It depends on the number of ion channels number (changes)
Higher = Higher λ
Why do some dendrites have VG ion channels? - Answer-They can act as small
postsynaptic potential amplifiers generated far out on dendrites
What factors effect an EPSP's output on a neuron? - Answer-Number of coactive
excitatory synapses, the distance the synapse is form the spike-initiation zone, and
the properties of the dendritic membrane.
Shunting Inhibition - Answer-When an inhibitory synapse acts as an electrical shunt
and prevents current from flowing through the soma to the axon hillock which is
usually inward movement of negatively charged Cl- ions.
Where are inhibitory synapses located usually? - Answer-On the soma and near the
axon hillock where they have a powerful position to affect the neuron action
Modulation - Answer-A synapse where it affects the effectiveness of EPSPs
generated by other synapses with transmitter-gated channels
Norepinephrine (NE) - Answer-an amine NT that binds to ß receptors and triggers a
cascade of biochemical events within the cell that leads to modulation
Adenylyl Cyclase - Answer-enzyme that catalyzes the reaction to convert ATP into
cAMP
,Cyclic Adenosine Monophosphate (cAMP) - Answer-a second messenger molecule
that can stimulate other enzymes such as a protein kinase
Protein Kinases - Answer-enzyme that catalyzes phosphorylation to change another
protein
Phosphorylation - Answer-process that transfers phosphate groups from ATP to a
specific site on cell proteins to change its conformation and activity
What is an important effect of phosphorylation in neurons? - Answer-It can close a
particular type of K channels and thus lowering the membrane's K+ conductance
which increases the dendritic membrane resistance and increases λ
Otto Loewi - Answer-Discovered effect of acetylcholine, ACh (vagusstoff) through
experiments with frog hearts...He used this discovery to prove chemical synapses
Cholinergic - Answer-Introduced by Henry Dale. Described cells that produce and
release ACh as this.
Noradrenergic - Answer-Dale termed neurons that use the amine neurotransmitter
norepinephrine this...
Glutamatergic - Answer-Synapses that use glutamate
GABAergic - Answer-Synapses that use GABA
Peptidergic - Answer-Synapses that use peptides
Criteria for a neurotransmitter - Answer-Must be synthesized and stored in the
presynaptic neuron.
Must be released by presynaptic axon terminal upon stimulation
When experimentally applied, must produce a response in postsynaptic cell that
minus the response produced by the release of neurotransmitter from presynaptic
neuron
Important techniques to satisfy criteria for neurotransmitter - Answer-
Immunuocytochemistry and in situ hybridization
Immunochemistry: method for viewing location of specific molecules in sections of
brain tissue
In situ hybridization: Method for localizing specific mRNa transcripts for proteins.
Together, these methods enable us to see whether a neuron contains and
synthesizes a transmitter candidate.
Immunocytochemistry - Answer-Used to anatomically localize particular molecules to
particular cells. Once neurotransmitter candidate has been chemically purified, it is
injected into the bloodstream of an animal where it stimulates an immune response
(to evoke response, molecule is chemically coupled to larger molecule). One aspect
of immune response is generation of antibodies which tightly bind to specific sites of
foreign molecule (transmitter candidate). Better antibodies bind tightly to transmitter
of interest and very little or not at all to other chemicals. Antibodies are recovered
,from blood sample of immunized animal and chemically tagged with marker to see
under microscope. Used to localize molecule for which antibody can be generated
(synthesizing enzymes for transmitter candidates). Demonstration that transmitter
candidate and its synthesizing enzyme are contained in the same neuron or axon
terminal can help satisfy criterion.
http://o.quizlet.com/i/EMbNpIVPpPEq01qOZ_9LBQ.jpg
In Situ Hybridization - Answer-Chemically label probe (complementary strand of
mRNA), apply it to section of brain tissue, allow time for probes to stick to any
complementary RNA strands, then wash away all extra probes that haven't stuck.
Finally, search for neurons that contain label. Probes are usually labeled by making
them radioactive.
Technique for viewing distribution of radioactivity - Answer-autoradiography
Stimulate release in in vitro brains - Answer-Slices bathed in solution containing hihg
potassium concentration. Causes large membrane depolarization, stimulating
transmitter release from axon terminals in the tissue.
Microinophoresis - Answer-Assesses postsynaptic actions of transmitter candidate.
Inject charged candidate ions next to postsynaptic membrane and use
microelectrode to record effects on membrane potential.
No two neurotransmitters - Answer-bind to the same receptor
One neurotransmitter - Answer-can bind to many different receptors.
Excitatory Post-synaptic Potential (ESSP) - Answer-When the presynaptic NTs
causes a depolarization in the postsynaptic membrane.
Synaptic activation of ACh-activated and glutamate-gated ion channels causes them.
Inhibitory Post-Synaptic Potential (IPSP) - Answer-When te presynaptic NTs causes
hyperpolarization in the postsynaptic membrane.
Synaptic activation of Glycine-activated and GABA-gated ion channels causes them.
G-Protein Coupled Receptors - Answer-Receptors that can have a slower, longer-
lasting and much more diverse postsynaptic actions.
G-proteins - Answer-small proteins that are free to move along the intracelular face
of the postsynaptic membrane that can activate "effector" proteins to lead to
postsynaptic actions
Second messengers - Answer-molecules that diffuse away and activate additional
enzymes in the cytosol that can regulate ion channels and alter cellular metabolism.
Metabotropic Receptors - Answer-Another word for G-Protein Coupled Receptors
because they can trigger widespread metabolic effects
Autoreceptors - Answer-Presynaptic receptors that are sensitive to the NT released
by the presynaptic terminal.
, Used to regular itself so it doesn't release too much NT
Why must NTs be recovered and degraded quickly after its been released and how?
- Answer-Ot must be cleared so that the next action potential can cause another
synaptic transmission.
There are NT transports on the presynaptic membrane that allows for re-uptake so
enzyme can destroy them or be released back into vesicles. Glial cells also have
these so that they can regular the cleft. There also could be enzymes in the cleft that
destroys the NTs.
This prevents desensitization where the transmitter-gated channels won't respond to
the NTs on the postsynaptic side.
Neuropharmacology - Answer-Study of the effects of drugs on nervous system tissue
Inhibitors - Answer-Drugs that inhibit the normal function of specific proteins
Receptor Antagonists - Answer-Inhibitors of NT receptors that bind to and block the
receptors
Receptor Agonists - Answer-Drugs that mimic the normal actions of the naturally
occurring NT
Synaptic Integration - Answer-Process where multiple postsynaptic potentials
combine within one postsynaptic neuron.
Why at NTs quantally released? - Answer-A single vesicle has the same number of
NT molecules (several thousands) so depending on how many vesicles are
released, it will always be a multiple of that number.
Miniature PostSynaptic Potential - Answer-A response generated by one vesicle of
NTs
Quantal Analysis - Answer-We can compare the amplitudes of miniature and evoked
postsynaptic potentials to figure out how many vesicles is released during a synapse
transmission.
Neuromuscular = about 200 vesicles
CNS = about 1 vesicle
Receptor subtype - Answer-Each of the different receptors a neurotransmitter binds
to. ACh acts on two different cholinergic receptor subtypes: One present in skeletal
muscle and the other in heart muscle. Both subtypes are also present in many other
organs and within the CNS
Neuropharmacological Analysis - Answer-Distinguishing receptor types through the
use of drugs
Nicotinic ACh receptors - Answer-Skeletal muscle. Also exists in brain.
Muscarinic ACh receptors - Answer-Heart muscle. Also exists in brain.
WITH COMPLETE ANSWERS
EPSP Summation - Answer-The simplest form of synaptic integration in the CNS.
There are two types: spatial and temporal
Spatial Summation - Answer-addition of EPSPs generated simultaneously at many
different synapses on a dendrite
Temporal Summation - Answer-addition of EPSPs generated at the same synapses
as they occur in rapid succession (1/15 m sec apart)
Length Constant (λ) - Answer-Distance from the synapse where the depolarization is
37% of that at the origin
Internal resistance - Answer-The resistance of current flowing longitudinally down the
dendrite. It depends only on the diameter of the dendrite & electrical properties of the
cytoplasm (constant)
Higher = Lower λ
Membrane resistance - Answer-The resistance of current flowing across the
membrane. It depends on the number of ion channels number (changes)
Higher = Higher λ
Why do some dendrites have VG ion channels? - Answer-They can act as small
postsynaptic potential amplifiers generated far out on dendrites
What factors effect an EPSP's output on a neuron? - Answer-Number of coactive
excitatory synapses, the distance the synapse is form the spike-initiation zone, and
the properties of the dendritic membrane.
Shunting Inhibition - Answer-When an inhibitory synapse acts as an electrical shunt
and prevents current from flowing through the soma to the axon hillock which is
usually inward movement of negatively charged Cl- ions.
Where are inhibitory synapses located usually? - Answer-On the soma and near the
axon hillock where they have a powerful position to affect the neuron action
Modulation - Answer-A synapse where it affects the effectiveness of EPSPs
generated by other synapses with transmitter-gated channels
Norepinephrine (NE) - Answer-an amine NT that binds to ß receptors and triggers a
cascade of biochemical events within the cell that leads to modulation
Adenylyl Cyclase - Answer-enzyme that catalyzes the reaction to convert ATP into
cAMP
,Cyclic Adenosine Monophosphate (cAMP) - Answer-a second messenger molecule
that can stimulate other enzymes such as a protein kinase
Protein Kinases - Answer-enzyme that catalyzes phosphorylation to change another
protein
Phosphorylation - Answer-process that transfers phosphate groups from ATP to a
specific site on cell proteins to change its conformation and activity
What is an important effect of phosphorylation in neurons? - Answer-It can close a
particular type of K channels and thus lowering the membrane's K+ conductance
which increases the dendritic membrane resistance and increases λ
Otto Loewi - Answer-Discovered effect of acetylcholine, ACh (vagusstoff) through
experiments with frog hearts...He used this discovery to prove chemical synapses
Cholinergic - Answer-Introduced by Henry Dale. Described cells that produce and
release ACh as this.
Noradrenergic - Answer-Dale termed neurons that use the amine neurotransmitter
norepinephrine this...
Glutamatergic - Answer-Synapses that use glutamate
GABAergic - Answer-Synapses that use GABA
Peptidergic - Answer-Synapses that use peptides
Criteria for a neurotransmitter - Answer-Must be synthesized and stored in the
presynaptic neuron.
Must be released by presynaptic axon terminal upon stimulation
When experimentally applied, must produce a response in postsynaptic cell that
minus the response produced by the release of neurotransmitter from presynaptic
neuron
Important techniques to satisfy criteria for neurotransmitter - Answer-
Immunuocytochemistry and in situ hybridization
Immunochemistry: method for viewing location of specific molecules in sections of
brain tissue
In situ hybridization: Method for localizing specific mRNa transcripts for proteins.
Together, these methods enable us to see whether a neuron contains and
synthesizes a transmitter candidate.
Immunocytochemistry - Answer-Used to anatomically localize particular molecules to
particular cells. Once neurotransmitter candidate has been chemically purified, it is
injected into the bloodstream of an animal where it stimulates an immune response
(to evoke response, molecule is chemically coupled to larger molecule). One aspect
of immune response is generation of antibodies which tightly bind to specific sites of
foreign molecule (transmitter candidate). Better antibodies bind tightly to transmitter
of interest and very little or not at all to other chemicals. Antibodies are recovered
,from blood sample of immunized animal and chemically tagged with marker to see
under microscope. Used to localize molecule for which antibody can be generated
(synthesizing enzymes for transmitter candidates). Demonstration that transmitter
candidate and its synthesizing enzyme are contained in the same neuron or axon
terminal can help satisfy criterion.
http://o.quizlet.com/i/EMbNpIVPpPEq01qOZ_9LBQ.jpg
In Situ Hybridization - Answer-Chemically label probe (complementary strand of
mRNA), apply it to section of brain tissue, allow time for probes to stick to any
complementary RNA strands, then wash away all extra probes that haven't stuck.
Finally, search for neurons that contain label. Probes are usually labeled by making
them radioactive.
Technique for viewing distribution of radioactivity - Answer-autoradiography
Stimulate release in in vitro brains - Answer-Slices bathed in solution containing hihg
potassium concentration. Causes large membrane depolarization, stimulating
transmitter release from axon terminals in the tissue.
Microinophoresis - Answer-Assesses postsynaptic actions of transmitter candidate.
Inject charged candidate ions next to postsynaptic membrane and use
microelectrode to record effects on membrane potential.
No two neurotransmitters - Answer-bind to the same receptor
One neurotransmitter - Answer-can bind to many different receptors.
Excitatory Post-synaptic Potential (ESSP) - Answer-When the presynaptic NTs
causes a depolarization in the postsynaptic membrane.
Synaptic activation of ACh-activated and glutamate-gated ion channels causes them.
Inhibitory Post-Synaptic Potential (IPSP) - Answer-When te presynaptic NTs causes
hyperpolarization in the postsynaptic membrane.
Synaptic activation of Glycine-activated and GABA-gated ion channels causes them.
G-Protein Coupled Receptors - Answer-Receptors that can have a slower, longer-
lasting and much more diverse postsynaptic actions.
G-proteins - Answer-small proteins that are free to move along the intracelular face
of the postsynaptic membrane that can activate "effector" proteins to lead to
postsynaptic actions
Second messengers - Answer-molecules that diffuse away and activate additional
enzymes in the cytosol that can regulate ion channels and alter cellular metabolism.
Metabotropic Receptors - Answer-Another word for G-Protein Coupled Receptors
because they can trigger widespread metabolic effects
Autoreceptors - Answer-Presynaptic receptors that are sensitive to the NT released
by the presynaptic terminal.
, Used to regular itself so it doesn't release too much NT
Why must NTs be recovered and degraded quickly after its been released and how?
- Answer-Ot must be cleared so that the next action potential can cause another
synaptic transmission.
There are NT transports on the presynaptic membrane that allows for re-uptake so
enzyme can destroy them or be released back into vesicles. Glial cells also have
these so that they can regular the cleft. There also could be enzymes in the cleft that
destroys the NTs.
This prevents desensitization where the transmitter-gated channels won't respond to
the NTs on the postsynaptic side.
Neuropharmacology - Answer-Study of the effects of drugs on nervous system tissue
Inhibitors - Answer-Drugs that inhibit the normal function of specific proteins
Receptor Antagonists - Answer-Inhibitors of NT receptors that bind to and block the
receptors
Receptor Agonists - Answer-Drugs that mimic the normal actions of the naturally
occurring NT
Synaptic Integration - Answer-Process where multiple postsynaptic potentials
combine within one postsynaptic neuron.
Why at NTs quantally released? - Answer-A single vesicle has the same number of
NT molecules (several thousands) so depending on how many vesicles are
released, it will always be a multiple of that number.
Miniature PostSynaptic Potential - Answer-A response generated by one vesicle of
NTs
Quantal Analysis - Answer-We can compare the amplitudes of miniature and evoked
postsynaptic potentials to figure out how many vesicles is released during a synapse
transmission.
Neuromuscular = about 200 vesicles
CNS = about 1 vesicle
Receptor subtype - Answer-Each of the different receptors a neurotransmitter binds
to. ACh acts on two different cholinergic receptor subtypes: One present in skeletal
muscle and the other in heart muscle. Both subtypes are also present in many other
organs and within the CNS
Neuropharmacological Analysis - Answer-Distinguishing receptor types through the
use of drugs
Nicotinic ACh receptors - Answer-Skeletal muscle. Also exists in brain.
Muscarinic ACh receptors - Answer-Heart muscle. Also exists in brain.
