Twitch Contractions

The mechanical response of a single muscle fiber to a single action potential is known as a twitch. Figure 11-20a shows the main features of an isometric twitch. Following the action potential, there is an interval of a few milliseconds, known as the latent period, before the tension in the muscle fiber begins to increase. During this latent period, the processes associated with excitation-contraction coupling are occurring. The time interval from the beginning of tension development at the end of the latent period to the peak tension is the contraction time. Not all skeletal-muscle fibers have the same twitch contraction time. Some fast fibers have contraction times as short as 10 ms, whereas slower fibers may take 100 ms or longer. The duration of the

Vander et al.: Human Physiology: The Mechanism of Body Function, Eighth Edition

Muscle CHAPTER ELEVEN

Muscle CHAPTER ELEVEN

(a) Isometric contraction

■ Latent period

H Contraction time

(a) Isometric contraction

■ Latent period

H Contraction time

Twitch Contractions

[Single action I potential

[Single action I potential

(b) Isotonic contraction

[Single action I potential

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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Responses

  • william
    Which part of the body has a twitch contraction?
    6 years ago

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