Exploring Action Potentials: Lab Guide for BIOL 3040U
School
University of the Fraser Valley**We aren't endorsed by this school
Course
SOC 190
Subject
Biology
Date
Dec 12, 2024
Pages
2
Uploaded by DrScienceMongoose18
BIOL 3040U Lab 221 Flow chart Effect of Changing Ionic (Na+ and K+) Concentrations:Run the HHsim program.click on Stim1 to generate an AP.Click on the Membrane parameters window, use the text box or arrows to increase and decrease con.•Ans the questions.Design an experiment to determine the threshold potential•Use SigmaPlot or Excel to plot combinations of current strength (intensity) and•duration on a graph.•Strength-duration curve, relating intensity of an electrical stimulus to the length of time it must be applied to be effective. •Place the duration in milliseconds on the X axis and intensity in nanoAmps (nA) on the Y axis. •Create smooth excitability curve.•The smallest current that is adequate to trigger the AP is known as the rheobasic current or rheobase and occurs at the plateau.•The time needed to excite the cell with twice the rheobase current is a measure of the cell’s excitability and is known as chronaxy. This value is the time obtained from the intersection of the curve by a line twice the rheobase•Reduce the current until the AP is no longer elicited from 10nA •clicking on the Stimuli tab and modify the intensity of the stimulus •Find strength of a stimulus that does not elicit an AP, •Than increase the current by 1 nA•Determine the membrane potential by clicking on the red plot.
BIOL 3040U Lab 221 Flow chart Design an experiment to determine the relative refractory period.Effect of Pharmacological Agents•In the bottom plot change the parameters in the dropdown boxes to: gNa+ (pS), gK+ (pS), and h.•These values represent the conductance•. Nowthese parameters will be plotted on the plot directly below the simulation plot.•modify the concentrations of the pharmacological agents, click on the Drugs parameters window and use the text box or arrows to increase or decrease the concentrations.•Describe how TTX, TEA and pronase affects the AP?•Does lidocaine function in a similar manner to any of the three pharmacological agents•Add a second impulse, open the Stimulus parameters window and add a second impulse of the same intensity as the first by clicking on the scroll bar to modify the second impulse intensity (5 nA for both impulses) .•Use the scroll bar to modify the interstimulus interval.