Buccal oscillation and lung ventilation in a semi-aquatic turtle, Platysternon megacephalum
Buccal oscillation and lung ventilation in a semi-aquatic turtle, Platysternon megacephalum
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DOI：
10.1078/0944-2006-00015
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发表时间：
2001-01-01
期刊：
影响因子：
--
通讯作者：
Brainerd, EL
中科院分区：
文献类型：
--
作者：
Druzisky, KA;Brainerd, EL
爬行动物和两栖动物下支气管器的运动有助于许多行为，包括摄食、肺呼吸、口咽呼吸、体温调节、嗅觉、防御和展示。在一只半水栖海龟中，大头扁龟的X光视频和气孔肺图上的气流测量表明，没有证据表明水面以上的低支气管处的运动会导致肺膨胀，就像两栖动物和一些蜥蜴的口腔或舌状泵一样。相反，下支气管部的运动会产生进入和流出口腔的空气的对称摆动。这些口腔振荡的平均潮气量比肺通气量的平均潮气量(四个人的总和平均值)小7.8倍。与口腔摆动相关的气流按吸气和呼气的顺序发生，这与肺通风不同，后者发生在呼气和吸气之后。没有观察到口腔振荡和肺通气量之间固定的时间关系。呼吸期通常没有颊振荡，有时出现颊振荡而没有肺通气。当这两种行为同时发生时，肺通气的开始往往会中断口腔振荡。发现在口腔振荡周期的所有阶段都有肺呼吸的启动，这表明这两种行为的神经控制机制不是耦合的。口腔振荡和肺换气的发生模式随着时间的推移而变化，活动水平没有明显影响。
Movements of the hyobranchial apparatus in reptiles and amphibians contribute to many behaviors including feeding, lung ventilation, buccopharyngeal respiration, thermoregulation, olfaction, defense and display. In a semi-aquatic turtle, Platysternon megacephalum, x-ray video and airflow measurements from blowhole pneumotachogaphy show no evidence that above water hyobranchial movements contribute to lung inflation, as in the buccal or gular pump of amphibians and some lizards. Instead, hyobranchial movements produce symmetrical oscillations of air into and out of the buccal cavity. The mean tidal volume of these buccal oscillations is 7.8 times smaller than the mean tidal volume of lung ventilation (combined mean for four individuals). Airflow associated with buccal oscillation occurs in the sequence of inhalation followed by exhalation, distinguishing it from lung ventilation which occurs as exhalation followed by inhalation. No fixed temporal relationship between buccal oscillation and lung ventilation was observed. Periods of ventilation often occur without buccal oscillation and buccal oscillation sometimes occurs without lung ventilation. When the two behaviors occur together, the onset of lung ventilation often interrupts buccal oscillation. The initiation of lung ventilation was found to occur in all phases of the buccal oscillation cycle, suggesting that the neural control mechanisms of the two behaviors are not coupled. The pattern of occurrence of both buccal oscillation and lung ventilation was found to vary over time with no obvious effect of activity levels.