Exam 1 Flashcards
What is the Nernst equation?
Ex = (RT/zF)ln([Xoutside]/[Xinside])
What is the GHK equation?
Em = 61 x log((PNa[Na,out] + Pk[K,out] + PCl[Cl,in])/(PNa[Na,in] + Pk[K,in] + PCl[Cl,in])
High conductance is ___ resistance
Low
Low conductance is __ resistance
high
A capacitor consists of what 3 parts?
an insulator with two conductors on either side
Capacitance is
the ability of a system to store charge
Capacitance is proportional to…?
area of the conductors; more area = higher capacitance
distance between the conductors; more distance = less capacitance
In neurons, distance between conductors in a capacitor is…?
Myelin; more myelin = decreased capacitance = higher conduction velocity
What is the time constant?
Time it takes for voltage to decay within 37% of final value (in a capacitor)
What are 4 limitations of extracellular recordings?
Lower signal to noise ratio; recording in vicinity of axon; recording cell with substantial ionic leakage; less intracellular environmental control
What are two reasons that using patch clamp (and its variations) is useful?
More control over intracellular environment and can be coupled with molecular techniques (i.e., toxin binding)
What does increasing seal resistance do?
Reduce noise level and increase temporal resolution
What are the 4 kinds of patch clamp technique variations?
Inside out, outside out, whole cell, cell attached
What is inside out recording?
the inside leaflet of the membrane is facing out of the pipette, therefore can record (with wire on inside of pipette) what happens to the outside of the membrane based on changing the environment of the inside of the membrane (i.e., salt bath solutions)
What is outside out recording?
Outside of the membrane is facing out; inside of the membrane is facing the inside of the pipette. Can record what happens to the inside of the membrane (Wire inside the pipette) based on what you manipulate about the outside of the membrane (i.e., again, bath solution)
