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Lee Family Problems: The Yin and Yang of Membrane Physiology


Author(s)

Nickolas E. Millas
Department of Biology
Villanova University
Nathalie Musey
Department of Biology
Villanova University
Emily Duwan
Department of Biology
Villanova University
Philip J. Stephens
Department of Biology
Villanova University
phil.stephens@villanova.edu

Abstract

This interrupted case study follows "Elaina Lee" and her family through a series of medical mishaps. Elaina suffers a reaction to an overdose of an herbal remedy prescribed to her while studying abroad in Africa. Upon returning home, she feels unwell and has a mild seizure. Her brother, who stays with her overnight in the hospital, awakens to find that he cannot move his legs. The common thread between these two patients is an abnormal level of potassium in the extracellular fluid (hypokalemia and hyperkalemia). Students are given signs, symptoms, and medical data. The goal is to construct links between extracellular potassium concentration, resting membrane potential, and action potential activity while also considering the effect of various hormones on Na/K-ATPase pump activity. Originally developed for a one-semester animal physiology course taken by sophomore and junior science majors, this case study could also be used in general biology if the Nernst equation, used to calculate the equilibrium potential for potassium, is covered in this course.


Objectives

  • Calculate the equilibrium potential for potassium using the Nernst equation.
  • Describe how different levels of extracellular potassium affect the resting membrane potential.
  • Analyze the difference between the membrane potential and the threshold potential for action potential production.
  • Predict the effects of different levels of extracellular potassium on the excitability of nerves and muscles.
  • Explain how the activity of the Na/K ATPase pump can alter the resting membrane potential.
  • Describe the influence of thyroid hormones, adrenaline, and insulin on Na/K-ATPase pump activity.

Keywords

Hypokalemia; hyperkalemia; Nernst equation; membrane potential; action potential; thyroid gland; Na/K-ATPase pump; digoxin; thyrotoxic periodic paralysis; TPP

Topical Areas

N/A

Educational Level

Undergraduate lower division, Undergraduate upper division

Format

PDF

Type / Methods

Discussion, Interrupted

Language

English

Subject Headings

Cell Biology  |   Physiology  |   Neuroscience  |  


Date Posted

12/12/2014

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