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
