Neuron and introduction flashcards
From Iusmphysiology
def. of homeostasis resistance to change
came up with "homeostasis" Claude Bernard
recognized internal temperature control Claude Bernard
Walter Canon developed the concept of homeostasis
showed internal mechanisms controlled resistance to change Walter Canon
opposing forces are balanced equilibrium
no net transfer between compartments equilibrium
equilibrium movement is equal and opposite
equilibrium doesn't require energy to be maintained
steady state nothing is changing
requires energy to maintain steady state
interstitial fluid is the same as the plasma without... proteins (found in plasma but not...)
three components of feedback system sensor, effector, regulated variable
negative feedback is to stabilizing as positive feedback is to destabilizing (is to positive feedback as negative stabilizing is to...)
amount of body water in cells 2/3
aldosterone effect at the kidney release of potassium
aldosterone released by adrenal cortex
triggers adrenal cortex release of aldosterone high plasma K+
The ____ has higher K+ concentrations (cytoplasm, ECF) cytoplasm
In Nernst equation, chemical term is RT ln ([Xi] / [Xo])
In Nernst equation, electrical term is zxFVm
electrochemical force over a membrane (Ex) defined as Ex = 61.54 / Zx * Log [x0] / [xi]
normal resting cellular potential -70 mV
number of Na and K pumped by Na/K ATPase 3 Na out, 2 K in
two Na/K ATPase inhibitors (poisons) ouabain, digoxin
significance of D loop in ion channels sits in channel and determines specificity
simple spread (bumping of ions) along axon is called passive depolarization
approximate neuron voltage threshold for depolarization -55 mV
E sub-K represents what? the voltage at most negative hyperpolarized state
Tetrodotoxin inhibits what? voltage-gated Na channels
this type of AP conduction spreads in all directions passive conduction
the s4 domain is important to voltage-gated channels because it... senses the voltage
primary location of Na channels in neurons axon hillock and axon
absolute refractory period is responsible for what unique feature of APs? unidirectional travel
unidirectional travel of APs is enforced by the absolute refractory period provided by non-fxnal time of sodium channels
schwann cells wrap up to how many times around an axon 200
width of a node of ranvier 2 micrometers
channels found in nodes of ranvier lots of Na channels, no K channels
saltatory conduction is due to presence of myelin
why is saltatory conduction faster faster to have ions bump along in cytoplasm than to have to open every Na channel along the membrane
decay of AP caused by Resistance of cytoplasm, resistance of membrane (loos of ions / signal), non-fxn of Na channels
reason there is no hyperpolarization in nodes of ranvier because there are no K+ channels
orthodromic (synonym for) forward (unidirectional) conduction of AP
increased length constant, faster or slower faster
saltatory conduction length constant lower than passive conduction length constant? no, higher, faster
MS (mechanism, NS distribution) autoimmune rxn against myelin; CNS
CMT (mechanism, NS distribution) genetic, non-fxnal myelin; PNS
Guillian-Barre (mechanism, NS distribution) autoimmune after infection (molecular mimicry); PNS
Krabbe disease (mechanism, NS distribution) genetic, non-fxnal lysosomal protein, poor degradation of ga lactosylcera m ide beta-galactosidase; CNS and PNS
demyelination symptoms (4) slower conduction, total blockage, ectopic spike generation, cross-talk
expression of what determines shape of AP Na and K channels
main determinant of AP velocity diameter of axon
two connexon hemichannels make one gap jxn
gap jxns open in the presence of Ca++
connexins (of gap jxns) have how many domains 4
gap jxns have how many connexin subdomains 6
influx of what ion causes vesicle release in a neuron Ca++
three types of NT vesicles clear (40-50 nm), dense (100 nm), large dense (200)
clear NT vesicles hold ach, glycine, GABA, glutamate
glutamine or glutamate an NT? glutamate
large dense NT vesicles contain signaling peptides
Ca2+BS, Synaptobrevin, Syntaxin1, Snap25, NSF, Munc18 (fxn in vesicle release) detecting Ca++, Docking, Zipper formation, zipper formation, regulated, regulator
difference between short and long vesicle fusion: short fusion, vesicle can be reused
interface of neuron and muscle motor plate
these types of neuron fibers innervate more than one muscle fiber A-alpha neurons
EPP end plate potential (the influx of Na and Ca through Ach-ligated channels)
D loop on nicotinic channel selects for positively charged ions
GABAr has positively charged aa on it's D loop and lets in Cl, a negative ion
cardiac muscarinic receptors (one specific mechanism, result) increase polarization, decrease heart rate
rate the delay of the three synapse types (ionotropic, muscarinic, electrical) electrical < ionotropic < muscarinic
AP splitting performed with which type of synapse (electrical or chemical) electrical
this type of synapse holds pre and post cells together electrical
which is faster: chemical or electrical synapses electrical
easier to regulate: chemical or electrical synapses chemical (think kinases and phosphatases affecting ion channels)
memory fxns via chemical or electrical synapses chemical
constant use synapses use this type of vesicle release ribbon
ribbon vesicle release is also known as disk vesicle release
ribbon vesicle release uses this molecular motor kinesine
this protein tethers ribbon to presynaptic membrane bassoon
NO pathway (from production to activation) Ca+ rises, NO synthase activated, NO diffuses, activates adenylyl cyclase, PKG activated
NO signaling between neurons one-way or two-way? two-way
rate of anterograde axonal transport 0.5 meters / day
motor for anterograde axonal transport kinesin
motor for retrograde axonal transport dynein
cytoskeletal structure as rails for axonal transport microtubules
this type of synapse is good for syncronizing electrical
amplifying signal : chemical synapse :: decreasing signal : electrical synapse
astrocyte processing of glutamate takes up NT glutamate from cleft, processes to glutamine, releases for EAAT xport into presynaptic
mechanisms of AP modulation (2) spacial summation, temporal summation, activation of K+ influx channels
characteristic that distinguishes between two simultaneous AP input dendrite diameter
facilitaiton (definition) transient increase of the EPP / PSP during high frequency nerve stimulation
potentiation (definition) long-lived increase in release of NT at synapse because of high frequency nerve stimulation
synaptic depression (define) temporary decrease in synaptic transmission because of high stimulation and lack of NT / vesicles
habituation (define) slow loss of synaptic transmission because of low stimulation
myasthenia gravis (mechanism) autoimmune: antibodies against nicotinic receptor
Lambert-Eaton syndrome (mechanism) autoimmune: antibodies against the presynaptic Ca2+ channel
acetocholine esterase inhibitors (2) pyridostigmine, DFP
pyridostigmine, DFP (mechanism, effect) inhibit ache, increase signaling at synapse
botox (mechanism, therapy for (3)) inhibits NT vesicle fusion; cervical dystonia, strabismus, and spacticity
