Observations on the amphibian “diaphragm”

A gastrointestinal role for the amphibian ‘diaphragm’ of Xenopus laevis

“…This arrangement in relation to the lung was noted by Keith (1905), who also doubted that the amphibian 'diaphragm' had an inspiratory function. According to Snapper et al (1974), this muscle does display a respiratory related activation pattern and it may be that the muscle serves to prevent aerophagy. In a positive-pressure ventilating aquatic animal, there is a risk of forcing air into the stomach and further down the gastrointestinal tract.…”

A gastrointestinal role for the amphibian ‘diaphragm’ of Xenopus laevis

“…This arrangement in relation to the lung was noted by Keith (1905), who also doubted that the amphibian 'diaphragm' had an inspiratory function. According to Snapper et al (1974), this muscle does display a respiratory related activation pattern and it may be that the muscle serves to prevent aerophagy. In a positive-pressure ventilating aquatic animal, there is a risk of forcing air into the stomach and further down the gastrointestinal tract.…”

The diaphragm: two physiological muscles in one

“…However, electrical stimulation of the muscle between breaths was found to produce a very slight increase in pulmonary pressure in comparison to the pressure rises seen during buccal pump inflation. In fact the pressure rises are hardly larger than the pressure ripples generated by heartbeats (see figure 7 in Snapper et al. 1974).…”

On the anuran muscle pulmonum proprius

“…Two main functions have been suggested for the m. pulmonum proprius: respiratory (Snapper et al, 1974) and gastrointestinal (Pickering et al, 2004). Although the latter authors have demonstrated that m. pulmonum proprius acts as a lower oesophageal sphincter, they did not rule out other physiological roles such as preventing aerophagy or retracting the stomach after vomiting.…”

“…These observations raise the following question: is the lung-inserted muscle of Bombina, Pelophylax and Rana homologous to the m. pulmonum proprius described by Beddard for Pipa and Xenopus? Few works dealing with the axial musculature in anurans were published and only some of them had studied the m pulmonum proprius with either Xenopus or Pipa as model organism (Dunlap, 1960;de Jongh, 1972;Snapper, Tenney and McCann, 1974;De Troyer et al, 1981;Pickering, Campion and Jones, 2004;Uriona and Farmer, 2006;Kimura, 2010). Most of them have referenced the work of Keith (1905) although without mentioning where the presence of m. pulmonum proprius is demonstrated for non pipid anurans.…”

“…With respect to the function of the m. pulmonum proprius, most studies dealing with this aspect used Xenopus as the model organism (Snapper et al, 1974;Pickering et al, 2004). Two main functions have been suggested for the m. pulmonum proprius: respiratory (Snapper et al, 1974) and gastrointestinal (Pickering et al, 2004).…”

A gastrointestinal role for the amphibian ‘diaphragm’ of Xenopus laevis

“…This arrangement in relation to the lung was noted by Keith (1905), who also doubted that the amphibian 'diaphragm' had an inspiratory function. According to Snapper et al (1974), this muscle does display a respiratory related activation pattern and it may be that the muscle serves to prevent aerophagy. In a positive-pressure ventilating aquatic animal, there is a risk of forcing air into the stomach and further down the gastrointestinal tract.…”

The diaphragm: two physiological muscles in one

“…However, electrical stimulation of the muscle between breaths was found to produce a very slight increase in pulmonary pressure in comparison to the pressure rises seen during buccal pump inflation. In fact the pressure rises are hardly larger than the pressure ripples generated by heartbeats (see figure 7 in Snapper et al. 1974).…”

On the anuran muscle pulmonum proprius

“…Two main functions have been suggested for the m. pulmonum proprius: respiratory (Snapper et al, 1974) and gastrointestinal (Pickering et al, 2004). Although the latter authors have demonstrated that m. pulmonum proprius acts as a lower oesophageal sphincter, they did not rule out other physiological roles such as preventing aerophagy or retracting the stomach after vomiting.…”

“…These observations raise the following question: is the lung-inserted muscle of Bombina, Pelophylax and Rana homologous to the m. pulmonum proprius described by Beddard for Pipa and Xenopus? Few works dealing with the axial musculature in anurans were published and only some of them had studied the m pulmonum proprius with either Xenopus or Pipa as model organism (Dunlap, 1960;de Jongh, 1972;Snapper, Tenney and McCann, 1974;De Troyer et al, 1981;Pickering, Campion and Jones, 2004;Uriona and Farmer, 2006;Kimura, 2010). Most of them have referenced the work of Keith (1905) although without mentioning where the presence of m. pulmonum proprius is demonstrated for non pipid anurans.…”

“…With respect to the function of the m. pulmonum proprius, most studies dealing with this aspect used Xenopus as the model organism (Snapper et al, 1974;Pickering et al, 2004). Two main functions have been suggested for the m. pulmonum proprius: respiratory (Snapper et al, 1974) and gastrointestinal (Pickering et al, 2004).…”

A gastrointestinal role for the amphibian ‘diaphragm’ of Xenopus laevis

“…This arrangement in relation to the lung was noted by Keith (1905), who also doubted that the amphibian 'diaphragm' had an inspiratory function. According to Snapper et al (1974), this muscle does display a respiratory related activation pattern and it may be that the muscle serves to prevent aerophagy. In a positive-pressure ventilating aquatic animal, there is a risk of forcing air into the stomach and further down the gastrointestinal tract.…”

The diaphragm: two physiological muscles in one

“…However, electrical stimulation of the muscle between breaths was found to produce a very slight increase in pulmonary pressure in comparison to the pressure rises seen during buccal pump inflation. In fact the pressure rises are hardly larger than the pressure ripples generated by heartbeats (see figure 7 in Snapper et al. 1974).…”

On the anuran muscle pulmonum proprius

“…Two main functions have been suggested for the m. pulmonum proprius: respiratory (Snapper et al, 1974) and gastrointestinal (Pickering et al, 2004). Although the latter authors have demonstrated that m. pulmonum proprius acts as a lower oesophageal sphincter, they did not rule out other physiological roles such as preventing aerophagy or retracting the stomach after vomiting.…”

“…These observations raise the following question: is the lung-inserted muscle of Bombina, Pelophylax and Rana homologous to the m. pulmonum proprius described by Beddard for Pipa and Xenopus? Few works dealing with the axial musculature in anurans were published and only some of them had studied the m pulmonum proprius with either Xenopus or Pipa as model organism (Dunlap, 1960;de Jongh, 1972;Snapper, Tenney and McCann, 1974;De Troyer et al, 1981;Pickering, Campion and Jones, 2004;Uriona and Farmer, 2006;Kimura, 2010). Most of them have referenced the work of Keith (1905) although without mentioning where the presence of m. pulmonum proprius is demonstrated for non pipid anurans.…”

“…With respect to the function of the m. pulmonum proprius, most studies dealing with this aspect used Xenopus as the model organism (Snapper et al, 1974;Pickering et al, 2004). Two main functions have been suggested for the m. pulmonum proprius: respiratory (Snapper et al, 1974) and gastrointestinal (Pickering et al, 2004).…”