Neuron and introduction flashcards

From Iusmphysiology

Revision as of 23:49, 8 January 2011

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