Twitch response in the canine vocalis muscle.
The twitch response of the canine vocalis muscle was investigated through a series of experiments conducted in vitro. Samples of vocalis muscle were dissected and prepared from canine larynges a few minutes before death and kept in Krebs solution at a temperature of 37 +/- 1 degrees C and pH of 7.4 +/- 0.05. Field stimulation with parallel-plate silver electrodes was applied to study the twitch response of muscle samples. The peak tension and time course of isometric contraction of isolated muscle samples were measured electronically with a Cambridge Technology Dual Servo System (ergometer). Contraction time and 50% relaxation time of this muscle were measured for seven samples at various levels of strain. It was found that contraction time ranged between 22 and 32 ms and 50% relaxation time ranged between 17 and 37 ms. Results indicate that the vocalis muscle is a fast muscle capable of performing rapid maneuvers in support of changes in fundamental frequency.
Alipour-Haghighi
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Department of Speech Pathology and Audiology, Wendell Johnson Speech and Hearing Center, University of Iowa, Iowa City 52242.
Titze
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Durham
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D000818:Animals; D004285:Dogs; D004558:Electric Stimulation; D066298:In Vitro Techniques; D007821:Laryngeal Muscles / Q000502:physiology*; D009119:Muscle Contraction; D009132:Muscles / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014828:Vocalization, Animal / Q000502:physiology*