Abstract
Breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs. The valves at the two outlets of the buccal cavity (nares and glottis) need to be finely controlled throughout the bout for the expression of these complex respiratory behaviors. In this study, we use a technique based on the calculation of the coherence spectra between respiratory variables (buccal pressure; narial airflow; and lung pressure). Coherence was also used to quantify the effects of chemoreceptor and pulmonary mechanoreceptor input on narial and glottal valve behavior on normoxic, hypoxic, and hypercapnic toads with both intact and bilaterally sectioned pulmonary vagi. We found a significant reduction in narial coherence in hypoxic vagotomized toads indicating that pulmonary mechanoreceptor feedback modulates narial opening duration. An unexpectedly high coherence between Pl and Pb during non-respiratory buccal oscillations in hypercapnic toads indicated more forceful use of the buccal pump. We concluded that the coherence function reveals behaviors that are not apparent through visual inspection of ventilatory time series.
Highlights
Breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs
Visual b l inspection revealed that the flanks and lungs of the animals moved synchronously with non-respiratory buccal oscillations (NRBO), which could be significant to animals that breath hold on lung inflation
Respiratory coherence was significantly greater than NRBO coherence for the glottal valve, as expected since the valve opens during pulmonary ventilation
Summary
Breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs. Nonrespiratory buccal movements are commonly observed as a long series of low amplitude buccal movements that tidally ventilate the buccal cavity, while the glottal valve is kept closed. These buccal oscillations can be interspersed by periods of inactivity or pulmonary ventilation. A typical single breath begins with the opening of the glottal valve, which causes an initial passive expansion of the buccal cavity. This partially empties the lung and is followed by an active expansion phase in which fresh air is drawn in through the narial valves. During longer bouts of breathing, animals can combine inflation, deflation and balanced (no net change in lung volume) breaths to better wash out or exchange gases
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Brazilian journal of biology = Revista brasleira de biologia
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.