Comparative Physiology of the Nervous Control of Muscular Contraction

Go to book overview

CHAPTER 2 The Electrical Properties of Muscle Cells at Rest

IT was discovered more than a century ago by Matteucci and by du Bois-Reymond ( 1843) that electric currents can be obtained from isolated, living (striated) muscle and also that contraction of a muscle is associated with a brief electric potential change. The electric currents were eventually shown to be not merely incidental phenomena in muscle activity, but the means by which activation of the contractile substance is normally initiated in the animal body. The arrival of a nerve impulse at a muscle leads to the production of electric changes there, thus providing a means by which the nerves can initiate muscular contraction. The basis of this phenomenon will now be considered in some detail.


THE RESTING POTENTIAL OF A MUSCLE FIBRE

Historical. If a long strip is cut out of a muscle which has a regular structure and parallel fibres (e.g. frog's sartorius or semimembranosus), a cylinder of muscle is obtained with an undamaged central portion (if the dissection has been done carefully) and neat cuts at both ends. The undamaged portion may be regarded as normal living muscle at the time of excision, dying only slowly under good conditions. The terminal portions are already dead, and death will gradually extend inwards from the dead zones. There is a rough line of demarcation between living and dead parts of the muscle, so when a potential difference was observed between a cut end and the centre it was at first referred to as the demarcation potential. A similar potential can be recorded from an excised muscle or one in situ between an uninjured region and a region damaged chemically or by crushing. It was not unreasonable to suppose that the damage was itself responsible for the development of the potential difference and so it was also referred to as an injury potential.

-27-

Notes for this page

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this book

This book has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this book

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this page

Cited page

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited page

Bookmark this page
Comparative Physiology of the Nervous Control of Muscular Contraction
Table of contents

Table of contents

Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this book

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
/ 147

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

    Already a member? Log in now.