Cell M2: Module 2 Flashcards
junctions between neurons permitting direct passive flow of electrical current
electrical synapsis
junctions between nuerons that communicaate via the secretion of NT
chemical synapses
gap juntion channel is made of ________ which is made of __________
2 hemichannels made of 6 connexins each and a channel pore
are electrical synapses selectuve?
no nonselective and channel pore is very large
why electrical transmission over chemical in some instances
veyr fast
usually bidirectional
- good for flight responses or synchronation of neuron activity - interneurons
are electrical synapse - gap junctions- usually closed of open?
clsoed and only few open at one time for easy regulation
what can happen to gap junctino channels
they can be phosphporylate
what percent of synapses in brain are chemical
99%
common structural features of a chemcial synapse
presynaptic bouton synaptic vesicles active xone synaptic cleft postsynaptic specialization
zone at presynaptic membrane where eocytosis of NT through vesicles occue
active zone
post synaptic specialization
contains |NT receptos and signalling/ scaffolding protiesn
assymmertrical synapses are mostly
excitatory
ssymetrical synapses are mostly
inhibitory
symmetrical synapses –.
presynaptic active zone thickness ______ postysnaptive specialzation thickness
equals
asymmertrical synapses
presynaptic active zone thickness ______ postysnaptive specialzation thickness
presynaptic active zone thickness < postysnaptive specialzation thickness
____ vesicles contain amino acid NT and acetlycholine
small synaptic vesicales with little electron density
___ vesicles containe monoamines
small electron dense SV
_____ vesicles contain peptide neurotransmitters, large
large dense-core vesicles
excitatory synapses on dendritic spines
axospinous synapses
excitatory or inhibitory synapses on dendritic shafters
axodendritic synapses
mostly inhibitory synsapses onto cell bodies
axosomatoc synapses
inhibitory synapses on other axons and presynaptic boutons
axo-axonic synapsis
inhibitory, bidirection, synapses between dendrites
dendro-dendritic synapses
excitatory sunapses between a neuron and a muscle cell
neuromuscular junctions
reverse potention = ____ when there is no net chagre transfer across membrane
membrane potential
if Vm < Erev the flux of cations, or current is
inward flux of cations; inward currents; outward flux of anions
if Vm> Erev the flux of cations or current is
outward; outward curret; influx of anions
when a synapse is acticates and ligand ion channels open membrane potenitl __________________________
ALWays becomes more similar to reverse potential of an ion channel
post synaptic currents and potentials are _____ if reversal potential is more positive than the action potential threshold
excitatory
post synaptic currents and potentials are _____ if reverse potential is more negative than the action potential threshold
inhibitory
spatial summation:
when multiples single synapses are a tivated at the same time to electicit an eaction potential
if post synaptic potentials derived from sungle synapses are inhibitory it contribues to _____
the prevention of action potential initiation
mechanism to amplify excitator input at distance synapses?
voltage gated conductances in denrites can amplify local Excitaoty post synapsetuc potentials with denritie spikes
