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
olfactory neuron replacement schedule; 4-8 weeks
generate new olfactory neurons; basal cells
smelled chemicals must be; water soluble
olfactory neurons are pretty normal neurons (T/F); T
olfactory receptor is what type of protein; g-protein
olfactory g-protein receptor proteins use this second messenger; cAMP
these cells inhibit olfactory neurons; granular and perigranular cells
what happens at the olfactory glomerulus; <1000 afferent neurons converge to stimulate a single olfactory neuron
rod cone distribution at fovea; rod << cone
type of neuron in vision; bipolar neuron
location of dendrite confluence in retinal neuron; ganglion cells
these glial cells support bipolar vision cells; mueller cells
contents of pigment epithelium; supporting cells that are the source of nutrients
provide color vision; cones
provide black and white vision; rods
two distinct sections of rods and cones; inner and outer segments
site of nucleus and mt in rods and cones; inner segment
reason rods and cones are depolarized even when asleep; inner segment secretes cGMP which activates cation channels
reason for hyperpolarization when sleeping; K+ channels are on to counteract secretion of cGMP from inner segment which opens cation channels
activated retinal found in what protein; meta-rhodopsin
rhodopsin activates transducin which; activates phosphodiesterase which cleaves cGMP to GMP
three types of what allow us to see three colors; opsins
tastebuds made of two types of cells; taste receptors, supporting cells
origin of taste receptors; epithelial tissue
synapses between taste receptors (type); electrical and chemical
type of synapse between taste receptor and neuron; chemical
four tastes; sweet, salty, bitter, umahni
salty taste mechanims; Na channels are always open allowing depolarization
bitter taste mechanims; acid detected, protein sensitive Na channels opened, depolarization
DAG's membrane receptor; TRMP5
IP3's ER receptor; IP3R
sweet taste receptor proteins; T1 / T2
umahni taste receptor protein; T1 / R3
bitter taste receptor protiens; T2
T1 / T2 / T3 / R3 receptor mechanism; g-protein coupled, phospholipase C activated, IP cut into DAG / IP3, Ca+ rushes in, depolarization
low and high frequency for humans; 20 khz, 200 hz
what is place coding; the specific area of the cochlear membrane that vibrates depending on the frequency
two types of hair cells; inner and outer
fxn of outer hair cells; fine tuning of inner hair cell sensitivity
prestin protein (found in which cells, useful for what); outer hair cells, contraction
rate coding; amplitude of sound corresponds to frequency of AP in hair cells
NT of hair cells to neurons; glutamate
hair cells use disks or ribbons?; disks
hair cell resting membrane potential (value, reason); -40 mV because outer hair cells are pressing on them causing opening of some channels
touch receptor; meissner receptor
pressure receptor; merkel's disks
vibration receptor; pacinian receptor
stretch / vibration receptor; ruffini ending
free nerve ending detects; cold, hot / dull pain
pleasure receptor; Krause's end bulb
meissner adaptation rate; rapid
merkel's disk adaptation rate; slow
pacinina adaptation rate; very rapid
ruffinian ending adaptation rate; slow
cold nerve ending receptor adaptation rate; fast
hot nerve ending receptor adaptation rate; slow
krause's end bulb adaptation rate; rapid
bundle of nerve fibers surrounded by onion of schwann cells; pacinina bulb
these sensory receptors have ENac and DEG; pacinian bulb
receptive field (definition); area of epithelium where stimuli triggers AP in a certain sensory nerve
receptors with small receptive fields (2); Meissner corpuscles, Merkel's disks
receptors with large receptive fields (2); pacinian bulbs, ruffinian endings
two types of pain fibers (myelinated?); a-fibers (yes), c-fibers (no)
three mechanisms of pain reception; P2x, ASIC, K+
p2x pain reception mechanism; ATP released from damage cells binds p2x anatropic receptors on nerve causing opening of cation channels, depolarization, and an AP
ASIC pain reception mechanism; organelles release protons, proton-sensitive cation channels open, depolarize, ap
K+ pain reception mechanism; K+ released by damaged cells, K+ ECF [] increases, neuron depolarizes
TRP channels important for detecting; temperature
these proteins detect falling temperatures; TRPA1, TRPM8
TRP protein structure; 4 subunits, 6 transmembrane domains, d loop
TRP allow what to pass; cations
cold versus hot, which one is a fast sensation; cold, via a-delta fibers
mechanism of the muscle spindle; when stretched, non-specific cation channels open, depolarize, ap
muscle spindle fast or slow adaptation; slow
intrafusals get sensory innervation or motor or both; both (so as to help the intrafusal muscle fibers shorten with the extrafusal)
location of golgi-tendon organ; in series with tendon and extrafusal muscles
this is detected by the golgi-tendon organ; tension
neuron will depolarize when ECF [K+] goes (up or down); up
