ARTICLE

OBLIQUELY STRIATED MUSCLE

Jack Rosenbluth ¹

¹ From the Department of Anatomy, Albert Einstein College of Medicine, New York, and the Departments of Physiology and Rehabilitation Medicine, New York University Medical Center, New York 10016

Segments of the obliquely striated body muscle of Ascaris were fixed at minimum body length after treatment with acetylcholine and at maximum body length after treatment with piperazine citrate and then studied by light and electron microscopy. Evidence was found for two mechanisms of length change: sliding of thin filaments with respect to thick filaments such as occurs in cross-striated muscle, and shearing of thick filaments with respect to each other such that the degree of their stagger increases with extension and decreases with shortening. The shearing mechanism could account for great extensibility in this muscle and in nonstriated muscles in general and could underlie other manifestations of "plasticity" as well. In addition, it is suggested that the contractile apparatus is attached to the endomysium in such a way that the sarcomeres can act either in series, as in cross-striated muscle, or individually. Since the sarcomeres are virtually longitudinal in orientation and are almost coextensive with the muscle fiber, it would, therefore, be possible for a single sarcomere contracting independently to develop tension effectively between widely separated points on the fiber surface, thus permitting very efficient maintenance of isometric tension.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

• Herrel, A., Meyers, J. J., Timmermans, J.-P., Nishikawa, K. C. (2002). Supercontracting muscle: producing tension over extreme muscle lengths. J. Exp. Biol. 205: 2167-2173 [Abstract] [Full Text]  

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents