Signal Transduction Flashcards
relationship b/w cytoplasms resistance and flow of current down the dendrite
more resistive cytoplasms will force more current to flow out across cell membrane rather than down axis of dendrite
length constant
distance where a graded potential has decreased to 37% of its original amplitude
length constant is dependent upon what 2 factors?
membrane resistance and axial resistance
large, myelinated axons will have longer length constants which means that??
graded potentials can travel over longer distances in large, myelinated axons before dying out
loss of signal strength
attenuation
relationship b/w length constant and attenuation
inversely proportional
increased length constant, decreased attenuation
relationship b/w diameter and length constant
directly proportional
increased diameter = increased length constant = decreased attenuation
what conditions decrease attenuation?
sharp termination of dendrite
increased diameter
branching ____ attenuation. why?
increases
b/c current has more paths to follow
most common autoimmune, demyelinating disease of PNS? CNS
Guillain-Barre Syndrome
Multiple Sclerosis
serves to increase membrane resistance, reduce capacitance of pathways b/w axoplasm & extracellular fluid
myelin
5 consequence of demyelination
- decreased conduction velocity
- frequency-related block
- total conduction block
- ectopic impulse generation
- increase in mechanosensitivity
glutamate & aspartate: inhibit? excite?
EXCITE
glycine and GABA: inhibit? excite?
inhibit
bouton terminal
presynaptic terminal
contain neuropeptides or small proteins that act as NTs and do not release their contents in active zone
dense-core secretory granules
attachment sites of synaptic vesicles are called
active zones
spatially focused networks
detailed neural mapping that allows one to read a sentence or play piano with precise timing
do not form ion channel pores BUT use signal transduction mechanisms to activate intracellular events using second messenger chemicals
metabotropic transmitter receptors (ex. GPCR)
neurons containing norepinephrine (locus coeruleus)
involved in regulation of:
attention arousal sleep-wake cycle learning memory pain anxiety mood brain metabolism
neurons containing serotonin (2 groups of raphe nuclei)
- involved in clinical depression
- fire most rapidly during wakefulness or when an animal is aroused/active
generation of dopamine containing cells in substantia nigra produces the progressively worsening motor dysfunction of what disease?
parkinson’s disease
location of neurons containing dopamine
substantia nigra
ventral tegmental area of midbrain
neurons containing Ach
general brain excitability during arousal, sleep wake cycles, learning, & memory formation
2 major diffuse modulatory cholinergic systems
basal forebrain complex
pontomesencephalotegmental complex
most EPSPs in brain are mediated by what types of channels?
glutamate-gated channels
what 2 types of receptors can glutamate act on?
ionotropic
metabotropic
mediates bulk of fast synaptic inhibition in CNS
GABA
ionotropic receptors that are chloride-selective channels
GABA (A receptor) and glycine
GABA-B receptor
a GPCR/metabotropic receptor linked to either opening of K+ channels or suppression of Ca++ channels.
in the presence of GABA, what are the effects of benzos and barbiturates?
benzos INCREASE FREQUENCY of channel opening
barbiturates INCREASE DURATION of channel opening
