synaptic transmission
clatherin
The membrane is removed by the use of ____ coted endocytosuis
synaptic cleft
The narrow gap that separates the presynaptic neuron from the postsynaptic cell.
Synapsin
The protein located on the outside of neurotransmitter vesicles in synaptic knobs which, when activated, causes them to fuse with the cell membrane and undergo exocytosis is:
executive and binding proteins
These are proteins involved in the SNARE complex to allow fusion
electrical synapses
(A) at ____ synapses, gap junctions occur between ore and post synaptic membrane. gap junction contain the channels passive current flow
chemical synapses
(C) at ____ synapses, there is no intracellular continuity, and no direct flow of current from pre to post synaptic cell. synaptic current flows across the membrane only in response to the secretion of neurotransmitters which open or close postsynaptic ion channels after binding to receptors
co-localization of neurotransmitters
-2 or more NTS within the same neuron -often neuropeptide co-localized with a small molecule NT
GTP
At the active zone, RAB is bound to ____ which does not allow the vessicle to dock
EPSPs
Excitatory postsynaptic potentials generated by depolarization , mostly mediated by glutamate (or aspartate) acting on AMPA or kainate receptors, occur in channels in which both Na+ and K+ can diffuse.
MEPPS
Fatt and Katz experiment: even when motor neurons were not stimulated, there were small changes in _____
Type I and Type II
In the central nervous system, there are two types of synapses.
recycling of the membrane
This occurs after fusion has occurred. Because the membrane gets bigger because of the vesicles plasma membrane fusion with the postsynaptic membrane.
readily releasable pool
Vesicles ready to be released are found in a region near the presynaptic terminal membrane called the ___
neurotransmitters
___ are synthesized by neurons. some are produced as byproduct of metabolism.
hydrolysis
_____of GTP is needed to break apart this complex which will allow the vesicle protein to interact with the docking complex
axon, neurotransmitters
action potential comes down to the end of the _____. stimulates the release of ______. this causes exocytosis and neurotransmitters are dumbed into the cleft and diffuse across the synaptic cleft. They bind to receptors on postsynaptic cell to activate it the neurotransmitters are removed from the synapse to prevent over stimulation
exocytosis
action potential in the terminus is a stimulus. opens voltage sensitive Ca channels opens with depolarization remains open as long as depolarization lasts. increase in Ca causes _____ of neurotransmitters into the synaptic cleft
axon terminus, transport proteins
amino acids and amines are synthesized in the _____. taken up into synaptic vesicle by way of _______ ______ because the they are charged and unable to diffuse through the bilayer
depolarization
amount of Neurotransmitters released increases as the membrane _____ increases. so action potential will cause release of a fixed amount of chemicals, but cells that don't create action potentials can also release NTs
protein mediated fusion pore
another mechanism of how vesciles are released
MEPPS
are about .5mV and occur randomly in the absence of no stimulus. This will occur when one vesicle released neurotransmitters.
presynaptic to postsynaptic
at electrical synapses, current flows directly from the _____ to the ___ cell.
dendrodendritic synapse
dendrite to dendrite. frequently reciprocal synapses. dendrites of one neuron can make synapses with dendrite on another neuron
Ca+
depolarization of the presynaptic terminal causes a increase in ___ permeability. The voltage gated Ca+ channel will open and cause calcium to flow down its concentration gradient from the outside to the inside of the synaptic terminal. Ca will interact with proteins associated with synaptic vesicles leads to the release of the chemical transmitter substance.
speeds
different transmitters are released with different ___. allows cells with co-localized transmitters to release them differentially based on cellular activity
motor end plate
generalized structure of chemical synapse. shows all structures. easy to get to as compared to chemical synapses within the CNS used as model chemical synapse
SNAP
helps to bind synaptobrevin to syntaxins to make the vesicles get closer and bind
remains
in chemical synapses, the current in the presynaptic cell ___ there. to get response in the postsynaptic, we must generate a new current
phosphorylated
influx of Ca+ ions activate kinases. synapsins release the vesicles when they are _____. vesicles are moved to the plasma membrane
synaptic cleft
mechanism of chemical transmission: it all relies on neurotransmitters they are relapsed by exocytosis from the presynaptic cell they diffuse across the ____ chemicals bind to receptors on postsynaptic cells. chemicals are removed from synapse. membrane is recycled
high frequency stimulation
more Ca coming in diffuses to the back part of the synaptic terminal. now we have neuropeptides released which can be released anywhere on the presynaptic membrane, doesn't have to be the bottom
chemical an chemical synapses
more common, found between neurons as well as between neurons and non neuronal cells. indirect current flow between cells. more adaptable/controllable
enzymes
neurons contain specific ____, used as a way of identifying subcategories of neurons.
Ca
neurotransmitter release is directly dependent on membrane depolarization. Not Sodium or potassium ion movement. It is dependent on ____ influx
SNARE complex
once the vesicle is able to bind, the _____ is created which is responsible for bringing the vesicle membrane closer to the plasma membrane
membrane
once vesicles are phosphorylates, they move to the active zone of the post-synaptic _____
soma, axonal
peptides are synthesized in the ___ in the ER. packaged into secretory vesicles in the Golgi. They are moved by _____ transport to axon terminus
synapse
point of transmission
junctional folds, postsynaptic densities, receptors
postsynaptic membrane structures
syntaxins
receptor protein found in the plasma membrane
type II synapses
smaller cleft, smaller active zones, decreased presynaptic densities, flattened or oval vesicles, little basement membrane
somasomatic synapse
soma of two neurons come together to make synapses. may see reciprocal synapses
synaptic knob
some vesicles are attached to sides of active zones. others are within the cytoplasm. Ca+ channels in close proximity to active zones
active zone, membrane, fusion pore
steps of exocytosis: 1. vesicles are restrained in pre-synaptic terminal 2. movement of vesicle to the _____ 3. docking of vesicles with protein on surface of vessicle with the _____ 4. priming 5. formation of _____ 6. release of neurotransmitters in postsynaptic vesicle 7. recycling of vessicle
axodendritic synapse
synapses between the axon endings of one neuron and the dendrites of other neurons. most common. most excitatory, some inhibitory. (a) in the picture
low frequency stimulation
synaptic vesicles are located near the presynaptic membrane. only these are exposed to Ca hence going under exocytosis.
function of electrical synapse
synchronization of the electrical activity of large populations of neurons. Hypothalamus, thalamus, neuronal development.
amplitude
the EPSPS are multiples of the unit synaptic potentials and the ____ depends on the number of vesicles released
gap junctions
the electrical synapses use ____, which are They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells.
phosphorylated
the influx of Ca+ ions will activate these kinases and cause the synapsis to be ______. This will cause the vesicles to be released from the actin
depolarization, Ca, into
the reason we get exocytosis of neurotransmitters in presynaptic cells, is because _______ opens voltage gated ___ channels causing Ca to come ___ the cell. Depolarization determines how long the channels are open for.
fusion pore
the release of neurotransmitters is a result of a _____.
lipid lined fusion pore
theory both membranes curve toward each other to form the early fusion pore. When the two membranes are brought to a "critical" distance, the lipid head-groups from one membrane insert into the other, creating the basis for the fusion pore.
Exocytosis
there are synaptic vesicles that release neurotransmitters that go through _____. from the pre-synaptic membrane they bind with the postsynaptic membrane to release neurotransmitters into postsynaptic to create a response
junctional folds
these are important because it increase the surface areas for where our receptors (neurotransmitters) are located
chaperones and synucleins
these work to prevent nonspecific interaction and misfolding's. They both support the formation of functional SNARE complexes by binding to SNAP or synaptobrevin
synaptotagamin
this binds to Ca+ which will allow for the fusion and is found in the vesicle membrane
glial and astrocytes
to clear neurotransmitters, we can use ____ and ____ to reuptake the neurotransmitters
enzymatic degradation
to remove neurotransmitters, you can use ____ which will use enzymes to chemically break them down
quanta
transmitter is released in small units called ____. one of these is one synaptic vessicle, which is about 5000 molecules of ACh
asymmetrical, excitatory
type I synapses are ___ in structure and _____ in nature
symmetrical, inhibitory
type II synapses are _____ in structure and _____
amino acids, amines, peptides
types of neurotransmitters
cAMP and Ca dependent kinases
types of synapsins
synapsins
vesicles are bound to actin by _____ proteins
synapsins
vesicles are bound to the pre-synaptic vesicle to actin by _______ proteins
exocytosis, capacitance
we have to undergo ____ because we add membrane to the button. we have to do this so the membrane does not get too big. and it changes electrical properties because it increases _____ and effects the function of the synapse
frequent
when depolarization of presynaptic cell occurred, the MEPPS became more _____, and they could block it with antagonists to abolish all spontaneous activity
desensitization
you must clear transmitters from cleft to prevent overstimulation of synaptic cells and _____
postsynaptic cell
cell which will receive information
presynaptic cell
cells which will convey information
axodendritic, axosomatic, axoaxonic
3 types of synapses and locations
active zone, fusion pore
1.restrain vesicles in (pre-synaptic) axon terminus 2.movement of vesicle to _____ where they will then fuse and cause release of NT upon influx of Ca 3.docking of vesicle (protein on surface and intracellular membrane) 4. priming 5. Formation of _____. vesicle and membrane proteins and release of Nts 6. recycling of vessicle via use of clathrin
Synaptotagmin
Ca+ might increase the pore size through the action of _____
Type I synapse
Large cleft, large active zone, dense projections from active zones, round vesicles, large postsynaptic density and basement membrane
MEPPs
Miniature end plate potentials
Ca2+
SNARE proteins bring the membranes together and ___ changes synaptoamin resulting in membrane fusion
axoaxonic synapse
axon terminal ends on another axon (C) picture
axosomatic synapse
axon to soma. primarily inhibitory
active zones
intracellular dense material adjacent to plasma membrane
synaptic bouton
is a structure in the presynaptic part that includes the synaptic vesicles, secretory vesicles, and active zones
EPPs
is due to the summation effects of many vesicles being released at the same time. One vesicle produces a potential of about 0.5 mV. The release of 200 of those vesicles at the same time could produce a potential which is 100 times as great (40 mV). so its due to many MEPPS
vesicles
less calcium means there will be less _____ released and therefore less neurotransmitters released. •levels of intracellular calcium ions in presynaptic cell determines how many vesicles undergo exocytosis at any given time
electrical synapse
less common, found predominantly in CNS, slow direct current spread from presynaptic to postsynaptic cell. allow for coordination of activity
synaptic transmission
mechanism by which neurons transfer information to other cells (communication with other neurons, muscle cells, glandular cells)