Neurobiology Assignment 2: Membrane & Action Potentials with NERVE Simulation, Assignments of Neurobiology

Download Neurobiology Assignment 2: Membrane & Action Potentials with NERVE Simulation and more Assignments Neurobiology in PDF only on Docsity! Assignment 2 Biol 6102 Neurobiology Due in class Tues Sept 2nd This exercise uses an online simulation program called NERVE. http://nerve.bsd.uchicago.edu/nerve1.html You are going to examine the properties of the membrane potential and the action potential. Follow the directions below and answer the questions on a separate page with your name on it. Click on the Membrane AP button. This will open a new window and you should see the Membrane Action Potential Window (right). Hit the F6 button or click Axon. This will open the Axon Parameters window. Click Ideal Channels. Click on the Membrane Action Potential Screen to the left of the red current pulse. Question 1) What is the resting membrane potential? p. 1 Hit the F7 button or click Pulses. This will open the Pulse Protocol window. Select the Amplitude box for Pulse 1. Enter new values for the pulse amplitude. Hit enter on the keyboard after changing the value and observe the Membrane Action Potential window. Question 2) What is the amplitude of a 0.25 ms current pulse needed to trigger an action potential? Question 3) What is the value of the membrane potential at threshold? Return the amplitude of PULSE 1 to 10μA. Now incrementally increase the amplitude of PULSE 3. Question 4) A. What is the threshold amplitude of the current needed to fire an action potential 6.5ms after the first stimulus? B. What is the amplitude of the membrane potential at the threshold? Hit the F8 button or click CONC. This will open the CONCENTRATIONS window Change [K]o to 50 mM as shown. Hit Enter. Question 5) A. What is the resting membrane potential now? B. Why did it change? Question 6) What happened to the action potential when you changed the potassium concentration? Hit the F9 button or click Var Plot. This will open the Variables to Plot window. Click on m and h. These are the sodium channel activation and inactivation variables. Question 7) Under which of the conditions of [K]o (10mM or 50mM) is h larger? Why? How does this relate to action potential? Explain your answer. p. 2