EPSPs increase the probability for an action potential to be generated because they let _____ into the cell body depolarizing the cell.
IPSPs decrease the probability for AP by
letting K out or chlorine in
direction of electrical synapses
electrical synapses are connected via
gap junctions (made of connexins)
what kind of pores do electrical synapses have? what do they let in
very large pores for unselective ion diffusion
what triggers vesicle fusion?
influx of ca through voltage gated ca channels
what happens if you have no Ca voltage gated channels
no NT release
what happens if you ↓ external [Ca]
↓ # of vesicles = ↓ postsynaptic potential
Ionotropic receptors - ligand-gated ion channels respond in ____
Metabotropic receptors - G-protein-linked receptors that respond in ___
sec/min (growth factor recpeotrs take even longer)
how does inactivation of chemical nt take place
via reuptake, glial uptake, diffusion, or enzymatic breakdown
what are the advantages of chemical synapses
directionality, amplification, plasticity, summation
what is facilitation
short-term synaptic plasticity
what does facilitation involve? what does it result in?
multiple action potentials in a short time (<50 msec) = ↑↑ in synaptic strength
describe the 2nd epsp after facilitation
2nd EPSP larger than the 1st because Ca clearance is slower than Ca entry into cell
how large are small molecule nt
50 nm diameter
how are small molecule NT stored?
in clear vesicles
some ___ are docked at active zones
small molecule nt
docked small molecule nt are released by
local ca influx
how are neuropeptides stored?
dense core vesicles
what is required for neuropeptide release?
high frequency stimulation
Vesicle release is quantal/discrete: each vesicle =
1 mini end plate potential
how do miniend plate potentials cause depolarization?
Many MEPPs make up the endplate potential, EPP, causing depolarization
how can you get larger mini end plate potentials?
more ach or more veiscles
neuron changes in synapse potential decrease with time and space
___ and ___ determine probability of an action potential due to leakage
Temporal and spatial summation
EPSP & IPSP amplitude & direction depend on
ion permeability and membrane voltage
NMDA is slower, Mg-blocked, but allows ___
GABA__ receptors are ligand-gated channels
GABA A receptors make __ with CL- ions