Pmcol 371 Midterm Exam Questions With Correct Answers
1 view 0 purchase
Course
PMCOL 371
Institution
PMCOL 371
Pmcol 371 Midterm Exam Questions With
Correct Answers
Formula for time constant of r//c - answerT= rm x cm, can find capacitance from measured T
Charging formula - answerV=iR (1-e^-t/T)
e^-1 is 0.37, so after one T of charging the voltage is 63% of the max value
Discharging formula - answerV=i...
Pmcol 371 Midterm Exam Questions With
Correct Answers
Formula for time constant of r//c - answer✔T= rm x cm, can find capacitance from measured T
Charging formula - answer✔V=iR (1-e^-t/T)
e^-1 is 0.37, so after one T of charging the voltage is 63% of the max value
Discharging formula - answer✔V=iR (e^-t/T)
e^-1 is 0.37, so after one T of discharge the voltage is 37% of the max value
Voltage and length constant formula - answer✔Vx=Vo(e^-x/y) where y is length constant and x
is distance from injection point
Length constant formula - answer✔y=square root of (rm/ri) (membrane resistance/axial
resistance)
Capacitor formula - answer✔C=Q/V
Q=C/V
Nernst equation - answer✔Ek=(RT/ZF) ln (Ko/Ki)
Z is valence
At 20 degrees, Ek= 58mV log (Ko/Ki)
For divalent divide by two, for anions add negative
Goldman-Hodgkin-Katz equation - answer✔Vm = 58log((Pk[k]out+PNa[Na]out +
PCl[Cl]in)/(Pk[k]in+PNa[Na]in)+ PCl[Cl]out )
You can use 58 because all ions are monovalent and you flipped Cl to reverse the charge
Ik (delayed rectifier) - answer✔-Delayed sigmoidal opening with multiple pre open states
-Preferentially conduct out due to only being open at positive voltages and due to K gradient
-Repolarizes AP
-Inactivates with longer current pulses, not on AP timescale
Retigabine - answer✔Im potassium channel opener/activator
-Lowers resting potential to suppress excitation, hyperpolarizing shift in voltage-dependence
(open at lower voltages), helps with epilepsy
Maxi K, Ca channels (BK channels) - answer✔-Depend on depolarization and intracellular
calcium
-High unitary conductance
-Intrinsic Ca-sensing mechanism
Iahp channels (SK channels) - answer✔-Weakly voltage dependent, strongly Ca dependent
-Low conductance
-Influx of Ca with APs activates channel to produce slow afterhyperpolarization (less Ca means
no AHP), relevant for bursts in rhythmic activity
-Extrinsic CA sensing via calmodulin binding site
-Blocked by apamin
Apamin - answer✔Blocks Iahp/SK, prevents slowing of APs after bursts
A-currents (Ia) / transient currents - answer✔-Activated by depolarization
-rapid inactivation by ball and chain (N-type)
-To reactivate, must hyperpolarize
-Example of encoding: higher stimulus causes Na to win over repolarizing, Ia cannot recover,
and APs happen at at a higher frequency
KIR (inward rectifiers) - answer✔-Pass current easier inward, but never do under physiological
conditions
-Allow small outward current near rest to maintain Vrest
-Quickly inhibited during depolarization, allows AP to fire
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Brightstars. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.49. You're not tied to anything after your purchase.
