QUESTION 4 What is the name of the change in Vm labeled B? +40 +20 Membrane potential difference (Vm) at rest - -20 Vm -40 Vm -60 В -80 A -100 -120 Time (msec) Membrane potential (mV)

Answer questions 1-5 about a cell that has: [ECF) of Na" = 142 mM, and K* = 4.6 mM (ICF] af Na* = 9 mM and K* = 155 mM The membrane has eight (8) times more K leak channels than Na*leak channels. 1. What is the resting membrane potential for this cell? 2. What would the resting membrane potential be if a drug was administered that blacked Na" leak channels? 3. To what would the membrane potential change if a stimulus apened an amount of Na* gated channels that was 500 times greater than the number af Na* leak channels? 4. What would be the direction of the Na* electrochemical gradient if the membrane potential were 80 mV? Into cell Out of cell 5. How much mare permeable would the above cell be to patassium than sodium if the measured resting membrane potential was -68 mv?

QUESTION 6 In a voltage clamp: O A. A constant current across the membrane is maintained in order to counter balance changes in membrane potential. O B. A variable voltage is applied across the membrane in order to maintain a constant membrane potential O C.Avariable current is applied across the cell membrane in response to changes in the ion concentration outside the cell. O D.Changes in current applied to a membrane in order to maintain a constant voltage represent the flow of ions through channels in the membrane O E. both A. and C. O F. Both B. and D.

Nervous Tissue electrical and chemical disequilibrium across cell membranes equilibrium potential calculating the equilibrium potential using the Nernst Equation The parameters of the Goldman Equation the reason for a -70mV resting'potential in most excitable cells gated channels particulars Defining depolarization, repolarization and hyperpolarization defining the role for the common ions, (K+, Na+ )special ions Cl, Ca+ have Define Current and ohm's law l=V/R Defining graded potentials and particulars about graded potentials such as subthreshold GP o suprathreshold GP temporal summation spatial summation e1 of 2 418 words English (United States) O Focus B I @ #3 24 & * 3 4 7 8