Tetanic Contraction in Vocal Fold Muscle Active properties of canine vocalis muscle tissue were investigated through a series of experiments conducted in vitro. Samples of the vocalis muscle were dissected from dog larynges excised a few minutes before death and kept in Krebs solution at a temperature of 37 ± 1°C and a pH of 7.4 ... Research Article
Research Article  |   June 01, 1989
Tetanic Contraction in Vocal Fold Muscle
 
Author Affiliations & Notes
  • Fariborz Alipour-Haghighi
    The University of Iowa
  • Ingo R. Titze
    The University of Iowa
  • Adrienne L. Perlman
    VA Medical Center, Iowa City
Article Information
Research Articles
Research Article   |   June 01, 1989
Tetanic Contraction in Vocal Fold Muscle
Journal of Speech, Language, and Hearing Research, June 1989, Vol. 32, 226-231. doi:10.1044/jshr.3202.226
History: Received December 30, 1987 , Accepted June 28, 1988
 
Journal of Speech, Language, and Hearing Research, June 1989, Vol. 32, 226-231. doi:10.1044/jshr.3202.226
History: Received December 30, 1987; Accepted June 28, 1988

Active properties of canine vocalis muscle tissue were investigated through a series of experiments conducted in vitro. Samples of the vocalis muscle were dissected from dog larynges excised a few minutes before death and kept in Krebs solution at a temperature of 37 ± 1°C and a pH of 7.4 ± 0.05. Isometric and isotonic tetanic responses of the vocalis muscle were obtained electronically with a Dual Servo System (ergometer). Isometric tension was recorded at various levels of elongation and stimulation rate. Isotonic shortening was recorded at various levels of force, and shortening velocity was obtained by numerical analysis of recorded data. It was found that fused tetanus occurred at stimulation rates of about 90 Hz, where the isometric titanic force saturates. Repeated stimulation of the muscle in vitro not only caused nonrecoverable fatigue in the tissue, but also decreased its passive tension. The combined active and passive isometric tension increased with elongation of the muscle. Results of isometric active responses were normalized with respect to average passive response. This normalization allowed for better comparison between tetanic contraction and twitch contraction. It was found that maximum tetanic contraction was 6.4 times greater than maximum twitch contraction obtained in a previous study. A tetanic contraction period was defined and investigated for eight samples of vocalis muscle tissue from different dogs. The tetanic contraction period showed a linear increasing trend with strain.

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