Control of jaw movements in two species of macropodines (Macropus eugenii and Macropus rufus)
| Autor: | Daniel E. Lieberman, Jayne Skinner, Tomasz Owerkowicz, Russell V. Baudinette, Alfred W. Crompton, J. Barnet |
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| Rok vydání: | 2007 |
| Předmět: |
Macropodidae
Male Physiology Electromyography Masseter Muscle Movement Digital video Anatomy Mandible Biology biology.organism_classification Biochemistry Masticatory force stomatognathic system Jaw Species Specificity Neural control Animals Female Adductor muscles Molecular Biology Mastication Macropus Power stroke |
| Zdroj: | Comparative biochemistry and physiology. Part A, Molecularintegrative physiology. 150(2) |
| ISSN: | 1531-4332 |
| Popis: | The masticatory motor patterns of three tammar wallabies and two red kangaroos were determined by analyzing the pattern of electromyographic (EMG) activity of the jaw adductors and correlating it with lower jaw movements, as recorded by digital video and videoradiography. Transverse jaw movements were limited by the width of the upper incisal arcade. Molars engaged in food breakdown during two distinct occlusal phases characterized by abrupt changes in the direction of working-side hemimandible movement. Separate orthal (Phase I) and transverse (Phase II) trajectories were observed. The working-side lower jaw initially was drawn laterally by the balancing-side medial pterygoid and then orthally by overlapping activity in the balancing- and working-side temporalis and the balancing-side superficial masseter and medial pterygoid. Transverse movement occurred principally via the working-side medial pterygoid and superficial masseter. This pattern contrasted to that of placental herbivores, which are known to break down food when they move the working-side lower jaw transversely along a relatively longer linear path without changing direction during the power stroke. The placental trajectory results from overlapping activity in the working- and balancing-side adductor muscles, suggesting that macropods and placental herbivores have modified the primitive masticatory motor pattern in different ways. |
| Databáze: | OpenAIRE |
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