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PMCOL 371 EXAM LATEST UPDATE
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PMCOL 371 EXAM LATESTUPDATE
Fibronectin - Answer Neuronal Glycoprotein that is often glycosylated forming
glycocalyx. Important in development
N-CAM - Answer Neuronal Glycoprotein that is often glycosylated forming glycocalyx.
Important in neural cell adhesion molecule
Proteoglycans - Answer Neuronal Glycoprotein that is often glycosylated forming
glycocalyx. 95% carbohydrate.
Actin - Answer Cyptoplasmis protein that forms nodal points under the membrane
Ankyrin - Answer Cytoplasmic protein that binds to intrinsic proteins.
Increasing Capacitor Capacitance - Answer -Increase surface area of insulator,
connecting more capacitors in parallel (store more charge)
-Decrrease thickness of insulator, increase force of attraction b/w each side of insulator
Capactiance - Answer How much charge can be stored at a capacitor per certain
voltage applied across that capacitor. The charge accumulation across a capacitor
increases proportionally with the applied votlage.
Electrical Circuit of the Cell - Answer lipid membrane=thin insualtor, capacitor
closed ion channel=open circuit, infinite resistance
open ion channel with no voltage dependence=resistor,no variability
open ion change, voltage dependence=variable resistor
Typical Cell Constants - Answer >>Gohms per channel. ~1 uF/cm2 or ~5x10^3
nonovalent ion per um2 at -80 mV.
Isopotential - Answer - a small cell that is esentially round and has no thin processes
- long axon cannulated with an axial electrode.
Resistance vs Capacitance - Answer - cell capacitcane proportional to cell surface
membrane area
- cell conductance proportional to cell surface area
- cell resisatnce inversely proportional to cell surface area
,R//C Circuit - Answer Rise and fall of V and iR have exponenetial shape. Initally all
charge to capacitor, as time increase less current go to capacitor. V and iR the same
shape b/c V=iRxR. Without impulse, the currrents are flipped following the discharge of
the capacitor.
Time constant - Answer Charging V=iR(1-e^(-t/tau)). Dicsharge V=iR(e^(-t/tau)).
tau=rmxcm. rm measured by long enough current impulse stopping cm. r=\m=rinput or
V/ijected.
Changes in Tau - Answer Increases if membrane surface area white number of opened
channels remains unchanged (c increase, tau increase). Deacread if increase number
of opened channels, while membrane surface area remains unchanged (decrease
resistant, decrease tau)/ If cell increase its surface area while density of open channel
remains unchaged tau unchange (increase in cm proportional to decrease in rm.
Axial/Cytoplasmic Resistance - Answer open cirsuit, both ends of axon are sealed.
Current split 3 ways, rm and 2 ri's. If infinitely long, a fixed fraction of current flowing
along axoplasm will be lost after each segment. Fixed fractional loss of current at each
segment, dictates steady-state membrane potential will decay exponentially with
distance.
Length Constant - Answer SQRT(rm/ri).V=Ve^(-x/lambda). If less than 1, faster rise. If 1,
exponential. If greater than 1, slower than exponential. Most rapid channel immediate
after injurt.
Cell Attached - Answer Form Gigaohm seal, only record from patch.
Inside-Out Patch - Answer Cell attach, then pull with low Ca. Only record from patch.
Indise facing bath.
Whole Cell - Answer Cell attatched and break into cell, record from whole cell.
Outside-Out Cell - Answer Whole cell then pull, outside of cell fae bath. Only record from
patch.
Setting Bath and Pipette Conc to the Same - Answer Increase magnitude of current. Set
Ek to 0. Prevent rectification assoicated with normal gradient.
I-v Plot - Answer Slope of I-v plot is unitary conductance.
Permeability - Answer how easily a permeant ion can pass through the channel when it
opens.
Conductance - Answer dependent on the concentration of the permeant ion as charged
carriers.
Outwardly Rectifying - Answer Prefer to pass current out of the cell than into the cell.
Steeper slope than non-rectifyign straight line. Due to ion gradeint or properites of
channel.
, Nernst Equation - Answer E=(RT/ZF) ln ([Ko]/[Ki]) or 2.3 fold multiplication to E=58
log([Ko]/[Ki]). Conc. of fully idssociated ions. For divalent divide by 2.
Chord Conductance - Answer Average slope between 2 membrane potentials
Slope Conductance - Answer Instantaneous slope at a certain membrane potential
GHK Equation - Answer For multiple ions each with own passive channel, or all pass
indepently through same channel. V=58
log((pK[Ko]+pNa[Nao]+pCl[Cli])/(pK[Ki]+pNa[Nai]+pCl[Clo]))
Advantages of Ca - Answer Sensitivity: Signal>>>>noise, low noise, high signal
Speed: big gradient, rapid local increase in Ca
Selectivity: activates only local processes, domain rapidly collapses.
Safety: low sensitivity prevent spurious activation by ambient Ca.
L-Type - Answer Primarily skeletal and cardiac muscle.
Large unitary conductacne ~25pS
Long Lasting, slow inativation
High Voltage-Activated (~ -40mV)
Prefer to pass Ba
Long open time, inactivate slowly, prefer to be open.
Alpha1C, adn D are pore-forming subunits.
L-Type Pharmacology - Answer Blocked by dihydropyridines (nifedipine, nimodipine)
Dihydropyridine agonist, BAYK-8644 open channel
Verapamil block.
Blocked by inorganic blockers (Cd>Co>Ni)
Insensitive to toxins.
L-Type Modulation - Answer b-Adrenergics increase open probability via cAMP
N-Type - Answer Neuronal, Neither L nor T
Intermediate conductance (12-20pS) between L and T
Prefers to pass Ba, not as much as L-Type
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