# Course

Course Summary
Credit Type:
Course
ACE ID:
CSRA-0004
Organization:
Location:
Online
Length:
8 weeks (60 hours)
Dates Offered:
Credit Recommendation & Competencies
Level Credits (SH) Subject
Upper-Division Baccalaureate 2 Biology or Biomedical Engineering
Description

## Objective:

The course objective is to provide a knowledge; of the rules of electricity in solutions the sources of energy across membrane, the generation of electrical pulses (action potentials) by bioelectric membranes, and the propagation of these action potentials along fibers; discuss the origins of extracellular signals, the ones normally observed in measurements such as the ECG, EEG, and EMG; and introduce some core ideas about electrical stimulation from within and outside the active cells.

## Learning Outcomes:

• Interpret the polarity of Vm in terms of voltages inside as compared to outside cells
• Describe the function of the sodium-potassium pump
• State from memory an approximate value for RT/F
• Explain the mechanism by which membranes use salt water to create negative or positive trans-membrane voltages
• Describe the opening and closing of a channel in terms of probabilities
• Given the rate constants alpha and beta at a fixed Vm, determine the channel probabilities
• Compute how the channel probabilities change when voltage Vm changes
• Describe the purpose of each of the 4 model levels (1) alpha/beta (2) probabilities (3) ionic currents (4) trans-membrane voltage
• Estimate the change in trans-membrane potential over a short interval
• Select the characteristics that distinguish core-conductor from other models
• Given a list of trans-membrane potentials, decide where axial and trans-membrane currents can be found
• Compute axial currents in multiple fiber segments from trans-membrane potentials and fiber parameters
• Quantify the interval after propagation following one stimulus to the time when there will be another excitation wave following a 2nd stimulus
• Explain what the 'activation function' is
• Draw a strength-duration curve, and explain what it is
• Explain the concept of 'threshold' and give examples of threshold values
• Explain the conflict between Galvani and Volta
• Interpret the polarity of Im in terms of current flow into or out of a cell
• Determine the energy in Joules of an ordinary battery, given its specifications
• State the 'big 5' electrical field variables (potentials, field, force, current, sources) and be able to compute potentials from sources (the basis of extracellular bioelectric measurements such as the electrocardiogram) or find sources from potentials
• Find the equilibrium potential from ionic concentrations and relative permeability
• Describe the passive as compared to active responses to stimulation
• Estimate changes in each probability over a small interval
• Compute the ionic current of potassium, sodium, and chloride from the state variables
• State which ionic current is dominant during different phases of the action potential -- excitation, plateau, recovery
• Identify the differences between axial and trans-membrane currents
• Compute membrane currents at multiple sites from trans-membrane potentials
• Identify the differences between the propagation pattern following sub-threshold versus threshold stimuli
• Compute the changes in trans-membrane potentials and currents from one time to a short time later
• Identify the outcome of stimulating a fiber at both ends
• Explain why 'propagation' is different from 'movement'
• Identify and the quantify the sources of extracellular potentials in terms of membrane currents
• Recognize which side of an excitation wave is positive, and which is negative
• Describe the sources and characteristics of no fewer than 3 kinds of extracellular bioelectric measurements, including the important features used in interpreting them
• In equation form, show the dependence with distance of a unipolar extracellular stimulus electrode
• Draw a strength-interval curve, and explain what it is

## General Topics:

• Electricity in solutions
• Energy- pumps and channels
• Channels - how membrane walls allow ions to pass through
• Hodgkin-Huxley model - how membranes generate action potentials by sequentially allowing ions of sodium and potassium to flow
• Axial and trans-membrane currents within and around the tissue structure
• Propagation - sequences of action potentials
• Extracellular observations - time-varying voltages between electrodes
• Trans-membrane and field stimulation to initiate or control excitation
• Evolutionary applications and misapplications
• Adaptive behaviors and species formation
Instruction & Assessment

## Instructional Strategies:

• Audio Visual Materials
• Case Studies
• Computer Based Training
• Discussion
• Lectures
• Practical Exercises
Supplemental Materials