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Chapter Seven
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303
Biology
Undergraduate 3
09/30/2012

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Term
What are the major subdivisions of the CNS?
Definition
Brain and spinal cord
Term
What conduct impulses into the CNS? 2 names
Definition
afferent or sensory neurons
Term
What conduct impulses out of the CNS to muscles and organs?
Definition
efferent neurons or motor
Term
What are somatic motorneurons?
Definition
Reflex and voluntary control of skeletal muscle
Term
What are autonomic motor neurons?
Definition
involuntary effectors; smooth muscle, cardiac muscle, glands
Term
What two places will you find autonomic motor neurons?
Definition
sympathetic and parasympathetic
Term
What are interneurons and where are they located? (what is another name for them?)
Definition
associative neurons, they are in the CNS and serve integrative functions
Term
What is the basic functional unit of the CNS and PNS?
Definition
neurons
Term
What do neurons respond to?
Definition
physical and chemical stimuli
Term
What do neurons conduct?
Definition
electrical impulses
Term
What do neurons release?
Definition
chemical mediators (neurotransmitter)
Term
What aids in perception of sensory stimuli, learning, and memory?
Definition
neurons
Term
In what system do neurons have limited capacity to divide?
Definition
CNS
Term
anatomy of the neuron
Definition
n/a
Term
Where does perception of sensory stimuli, learning and memory begin?
Definition
dendrites
Term
What is the general direction of flow of information?
Definition
dendrites to axon terminus
Term
Where is the energy summed in a neuron?
Definition
the axon hillock
Term
With the three types of organelle/protein transport within a neuron, what is the speed (fastest to slowest) 3
Definition
Anterograde>retrograde>apoplasmic (anterograde and retrograde fall under "axonal")
Term
What is axoplasmic transport?
Definition
cytoplasmic streaming (like waves washing up on a beach)
Term
Is axoplasmic transport specific or nonspecific?
Definition
Non specific
Term
What is anterograde?
Definition
transport (cell body to axon) is fast: moves toward the synapse (fastest)
Term
What is retrograde?
Definition
transport moves macromolecules and organelles back toward the nucleus (slower)
Term
What are characteristics of axonal transport? 3 points
Definition
1) macromolecules, organelles, proteins originate in or near the cel body
2) transported down the axon on the cytoskeleton, using ATP, Ca, and motor proteins
3) Moves mitochondria, golgi vessels and synaptic proteins
Term
Herpes virus
Definition
latent existence in axon terminus. When it is activated it moved to cell body and nucleus
Term
What type of transport is Herpres virus using when activated?
Definition
retrograde
Term
How does rabies virus gain access to the nucleus?
Definition
retrograde transport
Term
What does ganglia refer to? & where do you find them?
Definition
buncles of cell bodies (can be in CNS and PNS)
Term
Nerves are... & location
Definition
bundles of axons, located outside of CNS
Term
A single nerve can contain _____ and _____ neurons
Definition
sensory, motor
Term
What are support cells collectively referred to in the CNS?
Definition
glia
Term
Compared to neurons, what displayed limited mitotic activity?
Definition
glia cells
Term
What does the complexity of organisms seem to be related to?
Definition
more related to the ratio of support cells to neurons
Term
What are the types of support cells in the PNS?
Definition
Schwann, satellite
Term
What are the support cells in the CNS?
Definition
Oligodendrocytes, microglia, astrocytes, ependymal cells
Term
Where are Schwann cells found?
Definition
PNS
Term
What is the structure of Schwann cells?
Definition
they are wrapped once around axons of the PNS
Term
What are the functions of the Schwann cells?
Definition
protection, insulation for improved conduction of action potentials
Term
One Schwann cell: _____ ______
Definition
one axon
Term
What have myelin sheaths?
Definition
SOME axons in the PNS and CNS
Term
How is the myelin sheath formed in the PNS?
Definition
successive wrappings of Schwann cells around an axon like a roll of tape
Term
What are myelin sheaths formed by in the CNS?
Definition
oligodendrocytes
Term
What happens to the cytoplasm of a Schwann cell as it wraps around the neuron? What is true about the portion that remains?
Definition
it is forced into the outlying cell body, the remaining around the cell body is the protein myelin
Term
Neurons larger than ___ are usually myrlinated
Definition
2um
Term
Myelin= _____. It improves ___
Definition
insulation, signal conductance
Term
What are the nodes of ranvier?
Definition
the gaps between the schwann cells (they wont overlap)
Term
What is responsible for myelination in the CNS?
Definition
oligodendrocytes
Term
What are the differences between schwann cells and oligodendrocytes?
Definition
oligo wrap multiple neurons, the locations, oligo develop post natally, and oligo presence/absence determines gray/white matter
Term
One oligodendrocyte has cytoplasmic extensions that each wrap around an axon, ________
Definition
forming a myelin sheath
Term
An individual oligodendrocyte can wrap around _____ axons
Definition
multiple
Term
When do oligo. develop?
Definition
postnatally
Term
Myelin sheath in the CNS is what color?
Definition
white
Term
areas of the CNS rich in axons are termed "__"
Definition
white matter
Term
Areas of the CNS with mostly cell bodies and dendrites are termed "__"
Definition
gray matter
Term
What does multiple sclerosis do?
Definition
destroys myelination in the CNS
Term
What is the structure of an astrocyte?
Definition
star shaped!
Term
Where do you find end feet and what do they do?
Definition
Astrocytes, they surround microvessels and synapses.
Term
Endfeet are rich in what?
Definition
glucose transporters
Term
What are the 4 functions of astrocytes?
Definition
a) communication between neurons and the vasculature
b) Supplies energy (lactic acid)
c) K+spacial buffering
d) removal of neurotransmitters
Term
What is vasculature
Definition
regulation of blood supply
Term
How do astrocytes remove neurotransmitters?
Definition
They take up glutamate, convert it to glutamine. Glutamine is released to neurons for synthesis of glutamate.
Term
What is glutamate
Definition
a neurotransmitter (an agonist for signal receptors)
Term
What is glutamine
Definition
a precursor for glutamate
Term
astrocytes _____ glutamate and ____ glutamine
Definition
take in, release
Term
astrocytes signal to other glia through what?
Definition
gap junctions
Term
Astrocytes signal support from what 3 things?
Definition
cells, microvessels and neurons
Term
What is the best way to treat CNS trauma? What does this mean regarding astrocytes?
Definition
Improve the support cell function--you want to trigger astrocytes
Term
What are the 4 neural support cells?
Definition
microglia, oligodendrocytes, astrocytes, ependymal cells
Term
Microglia: why is the brain immune privileged?
Definition
BBB, brain remodeling, and the fact that the brian is 'protected' to prevent inflammation because brain isnt equipped to remodel
Term
What does the BBB need?
Definition
astrocytes and endothelial cells
Term
What should you think of when you see microglia?
Definition
macrophages/phagocyte
Term
Where do you find ependymal cells?
Definition
CNS
Term
What do ependymal cells do and where are they in the CNS?
Definition
lining ventricles in the brain, and they priduce/regulate cerebral spinal fluid
Term
What are ependymal cells associated with?
Definition
hydrocephalus
Term
Where do you find satellite cells?
Definition
CNS
Term
What do satellite cells do?
Definition
regulate chemical environment
Term
How do astrocytes regulate chemical environment?
Definition
See functions, just questioned differently
Term
Do CNS neurons regenerate spontaneously?
Definition
not typically
Term
What are the factors limiting spontaneous regeneration in the CNS? 3
Definition
1) inhibitory factors present in the CNS myelin
2) accumulation of proteoglycans associated with astroglial scarring
3) Difficulty in reforming numerous connections
Term
Can peripheral nerves regenerate?
Definition
yes
Term
If a PNS neuron is severed, how is it fixed?
Definition
the distal portion of the axon is phagocytized by schwann cells and macrophages
Term
What do schwann cells form to guide the regenerating axon to its target?
Definition
regeneration tube
Term
What factors help in PNS regeneration? what cells are they secreted by?
Definition
trophic factors: schwann cells and microglia
Term
Large peripheral nerves can be reconnected ____
Definition
surgically
Term
Neurotrophin defined
Definition
molecules that promote growth and development
Term
Where do you find neurotrophins?
Definition
fetal brain
Term
What are examples of neurotrophins
Definition
Nerve growth factor, brain derived neurotrophic factor, neurotrophins 1-5
Term
What is required in adults for nerve maintenance?
Definition
neurotrophins
Term
What is important in nerve regeneration?
Definition
neurotrophins
Term
What pathway do neurotrophins work though?
Definition
tyrosine kinase linked receptors: autophosphorilation
Term
What proteins help nerve development and function?
Definition
neurotrophins
Term
How are neurotrophins available in children and adults?
Definition
as agonists
Term
What is related to reduced plasticity in adults?
Definition
number of neurotrophins
Term
Define plasticity
Definition
The ability to correct damage
Term
What is the structure of the BBB
Definition
The brain capillaries do not have pores between endothelial cells
Term
What are brain endothelial cells joined together by?
Definition
tight junctions
Term
What may regulate permeability of endothelial cells?
Definition
astrocytes
Term
What type of molecules will cross the BBB
Definition
lipophilic
Term
Water soluble molecules require what to enter the CNS?
Definition
active/facilitated transport
Term
Parkinsons: What neurotransmitter is related to it?
Definition
lacks dopamine-->less signal transduction
Use LDopa because it is a precursor for dopamine
Term
Neurons have an RMP of: which side is more negative?
Definition
-70: inside is more negative
Term
Neurons can alter their membrane potential in response to _____
Definition
stimulation
Term
Define excitability
Definition
altering the plasma membrane permeability to ions, through activation of channels
Term
What is associated with depolarization?
Definition
becomes more positive, Na+ enters the cell
Term
What is associated with hyperpolarization?
Definition
cell becomes more negative, with a leaving of K+
Term
After a hyperpolarization/depolarization, a return to RMP is termed a
Definition
repolarization
Term
What will the channel do with a depolarization?
Definition
Open
Term
Changes in RMP are monitored by ___ and ____
Definition
ROC/VOC
Term
After the cell is at resting potential, they will reach ____, which is threshold. At that point, ___ channels open until the cell reaches _____. Then the ____ channels close and ____ open and RMP returns to normal
Definition
-50, Na, +35, Na, K
Term
At what point to Na channels close and K channels open?
Definition
action potential **?
Term
How does the cell repolarize?
Definition
K+ leaving the cell
Term
Define cable properties
Definition
the ability of a neuron to transmit an electrical signal
Term
Stimuli below threshold are transmitted for ____ mm of an axon
Definition
1-2
Term
Do axons have good cable properties?
Definition
no
Term
Why can't neurotransmission rely only on cable properties?
Definition
No neuron could be longer than 2 mm.
Term
How do we improve cable properties?
Definition
myelination
Term
Do axons regenerate charge as they move along?
Definition
no
Term
What do depolarizations above threshhold create?
Definition
an electrical signal strong enough to propagate as an action potential
Term
How are action potentials transmitted?
Definition
from one small segment of an axon to another
Term
Threshold depolarization is strong enough in one segment to do what to the next segment?
Definition
open voltage gated channels in the next one
Term
Small changes in action potentials are/are not propagated
Definition
are not
Term
complete membrane depolarization is/is not propagated
Definition
is!
Term
How will local/weak depolarizations react?
Definition
are small and don't reach threshold: so wont send at all
Term
What is a threshold depolarization?
Definition
cell has gone to +35 and causes adjacent membrane to depolarize and generate action potential
Term
What are the two major differences between local responses and action potentials?
Definition
- action potential is a larger response and totally reverses the entire membrane potential
- action potential is propagated down the length of an action
Term
Are small changes in polarizations propagated down the length of an axon?
Definition
no
Term
What is the range of a localized response?
Definition
-35 to -40
Term
What is the value of the amplitude once an action potential is generate?
Definition
it is always the same: the membrane is completely depolarized
Term
Strength of depolarization ___ change the amplitude of depolarization
Definition
does not change
Term
What happens when there is a stronger depolarization?
Definition
the number of action potentials increases
Term
action potentials are ____, not ______ modulated
Definition
frequency, amplitude
Term
Why is the amplitude of depolarization all or none?
Definition
it either has the depolarization or it does not!
Term
How is stimulus intensity coded?
Definition
the frequency of action potentials. the number of action potentials is what matters.
Term
What are required in order for neurons to release neurotransmitters?
Definition
action potentials
Term
Neurotransmitters will trigger the release of what?
Definition
bioactive molecules such as hormones and contraction of muscle
Term
What are non-threshold changes?
Definition
changed in RMP that don't in and of themselves reach threshold
Term
T/F the cell experiences stimulatory and inhibitory signals at the same time which are integrated at the axon hillock of neurons
Definition
True
Term
If the stimulatory signals exceed the inhibitory signals, what occurs?
Definition
an action potential can result, so the cell can effect a change by releasing bioactive molecules that can change RMP in effector organs
Term
What is an action potential?
Definition
complete membrane depolarization (switching charges)
Term
Once threshold is reached and an action potential is fired...what happens?
Definition
the cell will respond ( releasing neurotransmitter ) if the stimulus is sufficiently strong, more action potentials will be generated and the cell will release more neurotransmitter
Term
What is a nerve?
Definition
a bundle of axons
Term
what is the ganglia?
Definition
cell bodies
Term
for a given impulse, ____ of the axons may be stimulated
Definition
some
Term
as stimulus intensity increased, what happens to axon stimulation?
Definition
more axons are stimulated, each at an increased frequency.
Term
what is another way to increase response when the stimulus is "strong?"
Definition
recruitment
Term
What is the idea behind 'recruitment'?
Definition
More neurons are stimulated (each with the same amplitude of action potential) but they can stimulate more muscle fibers so the ability to do work increases.
Term
If action potential frequency increases, the time between them _____
Definition
decreases
Term
What is the absolute refractory period?
Definition
During an action potential spike, a neuron cannot respons to another stimulus
Term
What is the relative refractory period?
Definition
After the Na+ gates have closed and the K+ gates are open, a strong depolarization can produce a second action potential
Term
What is the principle ion movement during relative refractory periods?
Definition
K
Term
What is the principle ion movement during absolute refractory period?
Definition
Na moving in as well as K moving out
Term
What blocks voltage gated Na channels?
Definition
TTX
Term
What blocks Na+ channels?
Definition
Saxitoxin
Term
What is the principle ion movement during absolute refractory period?
Definition
Na moving in as well as K moving out
Term
What blocks voltage gated Na channels?
Definition
TTX
Term
What blocks Na+ channels?
Definition
Saxitoxin
Term
Where does the first action potential begin? (unmyelinated axon)
Definition
Axon hillock - Na enters the first segment of the axon, stimulating the cell
Term
What happens after Na enters the first segment of the unmyelinated axon?
Definition
Influx of Na and cable properties depolarize an adjacent 1-2 mm section of axonal membrane, that is still at the RMP of -70
Term
What happens in unmyelinated axon after the adjacent segment gets depolarized?
Definition
The Na flows in and another action potential is fired.
Term
What happens in unmyelinated axon after the second action potential is fired?
Definition
Adjacent regions continue to fire action potentials down the length of the axon. Each axon potential is a stimulus for the next segment in the sequence
Term
Are action potentials conducted?
Definition
Not really, they are regenerated along the length of the axon.
Term
When will some 'conductance' occur in axons?
Definition
when they are myelinated
Term
What happens to the amplitude of an action potential as it moves down an axon?
Definition
It remains constant (threshold is reached and the cell gets to +30)
Term
What three things are true of action potentials?
Definition
they are all or none, they move, and they occur without decrement
Term
Saltitory conduction refers to
Definition
myelinated neurons
Term
Where does depolarization occur in saltitory conduction?
Definition
the 1-2 mm myelinated segment
Term
What is the Node in saltitory conduction?
Definition
it is depolarized to threshold. Na Channels open and action potential is generated, this leads to second depolarization
Term
In myelinated axons, where is the action potential generated?
Definition
The Nodes
Term
The fewer action potentials you have, the ___ it will move
Definition
faster
Term
What 5 points are there about unmyelinated axons?
Definition
1) Conducted without decrement
2) Action potentials occur over entire length of axon
3) rate is slow
4) short distance conduction
5) Increasing axon diameter increases rate of conduction
Term
What 4 points are there about myelinated axons?
Definition
1) conducted without decrement
2) action potentials occur only at Nodes of Ranvier (saltitory conduction)
3) Long distance conduction
4) Insulating myelin makes conduction substantially faster - they can also have increased axon diameter
Term
Synapse
Definition
a functional connection between a neuron and another cell
Term
What is the synapse in CNS?
Definition
Neuron to neuron interaction
Term
What is the synapse in PNS?
Definition
neuron to neuron/effector cell such as a muscle or gland
Term
neuromuscular junction
Definition
synapse between a neuron and muscle
Term
What are the three examples of synapses occuring between different portions of neurons?
Definition
axodendritic, dendrodendritic, axosomatic
Term
What are the two types of synapses?
Definition
electrical and chemical
Term
electrical synapses defined
Definition
impulses flow uninterrupted from one cell to the next
Term
In electrical synapses, how are cells joined together?
Definition
gap junctions
Term
How far apart are membranes in electrical synapses?
Definition
2 mm
Term
Are electrical synapses one/two way conduction of impulses?
Definition
two way (based on concentration gradients)
Term
What are two examples of electrical synapses?
Definition
cardiac muscle and astrocytes
Term
How do electrical impulses communicate?
Definition
gap junctions
Term
What is the primary thing passing in electrical synapses
Definition
ions
Term
What are connexins?
Definition
in electrical synapses, they help pass information along
Term
Electrical synapses do not use ____ or ____
Definition
ligands or receptors
Term
Movement in an electrical synapse is limited by ___ and __________
Definition
size and concentration gradients
Term
Chemical synapses
Definition
transmission across the majority of CNS synapses is one way through a release of chemical neurotransmitters
Term
Does the CNS have gap junctions?
Definition
yes, but not too many of them, & since they release neurotransmitters, they primarily act through chemical synapses.
Term
What are some chemical neurotransmitters?
Definition
GABA, glutamate, ACh, epinephrine, serotonin, dopamine
Term
Chemical synapse image
Definition
[image]
Term
Post synaptic membranes contain ______ types of receptors
Definition
many
Term
Composition of neurons varies with
Definition
the type of neuron and neurotransmitter
Term
Activation of EPSPs causes
Definition
a depolarization
Term
Exitatory post synaptic potential changes the __
Definition
RMP
Term
What ions are involved in EPSPs?
Definition
Na, K, Ca
Term
EPSPs are _____ depolarizations that are ____
Definition
small, local
Term
IPSPs
Definition
Inhibit action potentials
Term
T/F Some receptors on the post-synaptic membrane may be inhibitory
Definition
True
Term
What does activation of inhibitory post synaptic receptors causes a ____ or ___
Definition
hyperpolarization or IPSP!
Term
IPSPs involve a decrease in _____, and increase in ____ or a decrease in _____
Definition
cAMP, Cl-, K+
Term
Signals (depolarizations) flow down the ____
Definition
dendrites
Term
Where are dendritic signals summed?
Definition
axon hillock- the decision to fire an action potential is made here
Term
What is a stimulus for an action potential?
Definition
depolarization
Term
What is the stimulus for EPSP/IPSP?
Definition
chemical
Term
What is the initial effect of EPSP/IPSP?
Definition
Receptor-operated effects
Term
What is the conduction distance for EPSP/IPSP?
Definition
localized, summed
Term
What is the max depolarization for EPSP/IPSP?
Definition
-70 to approx 0
Term
Are EPSP/IPSPs an all or none event?
Definition
No- EPSPs are summed, producing graded depolarization
Term
Is there a refractory period for EPSP/IPSPs?
Definition
no
Term
What are drug effects on EPSP/IPSP?
Definition
not inhibited by TTX, but by other receptor agonists
Term
Is there a threshold for EPSP/IPSPs?
Definition
No
Term
What is the location of EPSP/IPSPs?
Definition
Dendrites: processes information
Term
What is the initial effect of an action potential?
Definition
Na+ channels opening
Term
What is the conduction distance of an action potential?
Definition
the length of an axon
Term
What is the max depolarization of an action potential?
Definition
+40 mV
Term
is an action potential an all or none event?
Definition
yes
Term
does an action potential have a refractory period?
Definition
Yes
Term
What drugs affect an action potential?
Definition
TTX; it is inhibited
Term
is there a threshold for an action potential?
Definition
yes
Term
What is the location of an action potential?
Definition
axon: it conducts information
Term
What are the types of chemical neurotransmitters?
Definition
acetylcholine, monoamines (norepinephrine, dopamine, serotonin) and glutamate/glycine/GABA
Term
How does acetylcholine affect CNS neurons?
Definition
excitatory
Term
How does acetylcholine affect PNS?
Definition
excitatory in PNS somatic motor neurons
Term
Where can ACh be excitatory or inhibitory?
Definition
in the autonomic nervous system of the PNS: it depends on the organ involved
Term
Cholinergic
Definition
anything that binds ACh
Term
What are the two types of Ach Receptors?
Definition
Nicotinic and muscarinic
Term
Nicotinic ACh receptors work through what signal transduction pathway? Where do they predominate/where within that?
Definition
Receptor operated Channels. They predominate in the PNS at neuromuscular junction and in some areas of the CNS
Term
Muscarinic ACh receptors
Definition
G protein linked receptor of the Gq or Gi.
Predominates in CNS
Term
where do muscarinic receptors predominate?
Definition
CNS
Term
Where do nicotinic receptors predominate?
Definition
PNS
Term
Where are nicotinic receptors found (neuron)?
Definition
Post synaptic membrane
Term
Where are nicotinic receptors found (muscle)?
Definition
neuromuscular junction - motor endplate
Term
What blocks teh interaction of ACh with its receptor?
Definition
Curare
Term
How do you turn off a nicotinic ACh receptor?
Definition
Acetylcholinesterase: it degrades ACh bound to receptors (proteolytic degradation)
Term
Activation of the Nicotinic ACh receptor produces what?
Definition
an EPSP or IPSP at synapses between 2 cholinergic receptors (in nuronal and neuromuscular synapses
Term
What are produced at the neuromuscular junction?
Definition
EPSPs (at the postsynaptic membrane of the muscle fiber or motor end plate)
Term
What is the neuromuscular EPSP called?
Definition
endplate potential
Term
EPSP can cause (3)
Definition
depolarization open VOC in the muscle cell, causes action potential in muscle, contraction
Term
Nicotinic ACh receptor activation: Neuronal synapse (4)
Definition
1) produces an EPSP
2) Acts at the post synaptic neuronal membrane
3) Elicits depolarization
4) signal is summed at the axon hillock, to determine if threshold for actoin potential is reached
Term
Nicotinic ACh receptor activation: Neuromuscular Synapse (4)
Definition
1) Produces an EPSP (skeletal, not cardiac)
2) Acts at the motor end plate of skeletal muscle
3) Elicits an endplate potential
4) Signal produces depolarization of muscle membrane and contraction
Term
Will muscarinic Ach receptors directly affect the ion channel?
Definition
no
Term
What signal transduction pathway do muscarinic ACh receptors use?
Definition
G protein coupled (Gq and Gi)
Term
Effects of the muscarinic ACh receptors are tissue and organ ____
Definition
specific
Term
M1 Muscarinic Receptor
Definition
Bgamma subunits activate K+ channel - important in neuronal inhibition of the heart
Term
How do the Gamma cells affect the cardiac muscle in M1 muscarinic receptors?
Definition
gamma binds to K+ channels in pacemaker cells, K+ moves out, cells are hyperpolarized, producing an IPSP which slows heart rate
Term
Chemical neurotransmitters: monoamines
Definition
norepinephrine, dopamine, serotonin
Term
What are the catecholamines and what are they derived from?
Definition
norepinephrine and dopamine - they are derived from tyrosine
Term
What is serotonin derived from?
Definition
tryptophan
Term
Why is epinephrine not a neurotransmitter?
Definition
it is a hormone that is released into the blood.
Term
Do monoamines directly control ion channels?
Definition
No.
Term
How do monoamines affect the membrane?
Definition
through G proteins: primarily coupled to activation or inhibition of adenylate cyclase: Gi or Gq or Gs
Term
Monoamine neurotransmitters influence ___ and ____
Definition
mood, behavior
Term
Norepinephrine neurotransmission picture
Definition
[image]
Term
How are monoamine neurotransmitters terminated? (3)
Definition
1) reuptake of monoamines into presynaptic nerve terminals
2) Enzymatic degradation by monoamine oxidase
3) Enzymatic degradation of catecholamines by catechol-O-methyltransferase
Term
Will serotonin be affected by catechol-O-methyltransferase?
Definition
No, it is not a catecholamine
Term
What are monoamine oxidase inhibitors?
Definition
drugs that block the enzyme monoamine oxidase
Term
What do MAOs do?
Definition
block degradation of catecholamines and serotonin --> increase signal transduction
Term
What are MAOs used in treating?
Definition
clinical depression (suggests that a decrease in monoamine activity may contribute to this disorder) and Parkinsons
Term
There are many serotonergic neurons in areas of the _____
Definition
brain stem
Term
What foods increase serotonergic neurotransmission?
Definition
tryptophan-rich food: milk, turkey
Term
physiological functions of serotonin
Definition
regulation of mood, behavior, appetite, and cerebral circulation; depression
Term
All monoamines bind to
Definition
G protein receptors
Term
What do serotonin re-uptake inhibitors block?
Definition
the termination of serotonin action (by reuptake) at the presynaptic nerve terminals
Term
What is the effect of serotonin re-uptake inhibitors?
Definition
increase the amount of time serotonin is present
Term
Dopaminergic neurons are concentrated in the _____
Definition
midbrain
Term
What are the two divisions of dopanime
Definition
nigrostriatal and mesolimbic
Term
Where are nigrostriatal nerve pathways located?
Definition
(dopaminergic neuron subtype) the cerebrum: they are involved in skeletal muscle movement and coordination
Term
Where are mesolimbic nerve pathways located?
Definition
(dopaminergic neuron subtype) the midbrain and forebrain (part of the limbic system). dopamine signal released by these is associated with behavior/reward/effects.
- addictive drugs activate the mesolimbic dopaminergic system
Term
What is parkinson's characterized by?
Definition
muscle tremors/rigidity, impairment of movement, speech difficulities
Term
What is Parkinson's caused by?
Definition
degeneration of dopaminergic neurons of the nigrostiatal system ( though free radical generation from overactive microglia)
Term
How do you treat parkinson's?
Definition
L-Dopa (increases the amount of dopamine available) and MAO inhibitors (increase the amount of time dopamine is available)
Term
What is the potential benefit of microglia?
Definition
regeneration
Term
What are excitatory neurotransmitters?
Definition
Stimulatory in CNS: glutamate and Aspartic acid. Produce EPSPs in the brain
Term
Inhibitory neurotransmitters
Definition
Inhibitory in CNS: Glycine and Gamma-aminobutyric acid (GABA). Produced IPSPs in the brain.
Term
What is the major excitatory neurotransmitter in the brain?
Definition
Glutamate
Term
What are the two subdivisions of glutamate receptors?
Definition
ionotripic and metabotropic
Term
What do ionotropic receptors do?
Definition
(glutamate receptors) regulate post-synaptic ion channels: primarily in neurons, some in astrocytes
Term
What do metabotropic receptors do?
Definition
(glutamate receptors) regulate G protein linked signaling pathways. Neurons and astrocytes
Term
What are bound by glutamate?
Definition
ionotropic and metabotropic receptors
Term
Ionotropic glutamate receptors
Definition
-NMDA
-AMPA
Term
What is NMDA?
Definition
an ionotropic receptor: Abundant in the brain, regulates postsynaptic Ca2+ channels
Term
What is an AMPA receptor?
Definition
ionotropic glutamate receptor: abudant in the spinal cord: regulates a post synaptic Na+ channel
Term
What is a neurotransmitter that binds to VOC or ACh?
Definition
nicotinic
Term
NMDA receptor activation picture
Definition
[image]
Term
What are the three steps in NMDA receptor activation?
Definition
1) glycine or D-serine binding
2) Mg Leaving
3) binding of glutamate
Term
Metabotropic glutamate receptors link to what G proteins?
Definition
s q i
Term
What to metabotropic glutamate receptors regulate?
Definition
NMDA and AMPA receptors: maybe through kinase activation and phosphorylation of ion channels
Term
Where is calcium stored when metabotropic glutamate receptors?
Definition
dendritic postsynaptic spines
Term
What are metabotropic glutamate receptors critical to?
Definition
learning and memory
Term
What do inhibitory neurotransmitters produce?
Definition
an IPSP in postsynaptic dendrites
Term
What are two examples of inhibitory neurotransmitters?
Definition
glycine, GABA
Term
What is glycine important in controlling?
Definition
skeletal muscle movements
Term
How does glycine fit in the idea of flexing a muscle?
Definition
Motor neurons that counter the flexing are inhibited by IPSPs GENERATED BY glycine.
Term
Where is glycine found?
Definition
the spinal cord
Term
Glycine is the ____ muscle for muscle relaxation
Definition
antagonist
Term
What causes the antagonist muscle to relax when one muscle contracts?
Definition
glycine binding (spinal cord) through Cl coming into the cell, it becomes hyperpolarized, and inhibited
Term
What is the most prevalent neurotransmitter in the brain?
Definition
GABA
Term
___% of all brain neurons use GABA as _____
Definition
30, neurotransmitter
Term
What does GABA do to neurons in the brain?
Definition
hyperpolarize by opening postsynaptic Cl- channels
Term
Where is GABA important? (specifically)
Definition
in the cerebellum, it works with mediation of motor functions
Term
What is Huntington's Chorea
Definition
uncontrolled movements due to deficiency of GABA secreting neurons (muscles contracting when you shouldn't by preventing it from NOT contracting)
Term
What is long term potentiation?
Definition
Synapses stimulated with high frequencies exhibit increased post synaptic excitability
(BOOK: the improved efficacy of synaptic transmission
Term
How does LTP develop? (3)
Definition
1) change in phosphorylation state
2) change in neuronal lipid membrane structure (dendritic spines, alterations in receptor expression, NMDA, AMPA)
3) Alterations in intracellular calcium stores in the ER, particularly in the dendrites
4) Alteration in the level of gene transcription.
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