scholarly journals Mechanics of lung ventilation in a larval salamander Ambystoma tigrinum.

1998 ◽  
Vol 201 (20) ◽  
pp. 2891-2901 ◽  
Author(s):  
EL Brainerd

The larval stage of the tiger salamander Ambystoma tigrinum is entirely aquatic, but the larvae rely on their lungs for a large proportion of their oxygen uptake. X-ray video and pressure measurements from the buccal and body cavities demonstrate that the larvae inspire using a two-stroke buccal pump and exhale actively by contracting the hypaxial musculature to increase body pressure. Larvae begin a breath by expanding the buccal cavity to draw in air through the mouth, while simultaneously exhaling air from the lungs to mix with the fresh air in the buccal cavity. The mouth then closes, and the buccal cavity compresses to pump a portion of the mixture into the lungs. The remaining air in the buccal cavity is then released as bubbles from the mouth and gill slits. Ventilatory volumes estimated from X-ray video records indicate that approximately 80 % of the air pumped into the lungs is fresh air and 20 % is previously expired air. Exhalation in larval tiger salamanders is active, powered by contraction of all four layers of lateral hypaxial musculature. Electromyography indicates that the transverse abdominis (TA) muscle is active for the longest duration and shows the highest-amplitude activity, but the external oblique superficialis, the external oblique profundus and the internal oblique also show consistent, low-level activity. The finding that the TA muscle is active during exhalation in larval tiger salamanders contributes to a growing body of evidence that the use of the TA for exhalation is a primitive character for tetrapods.

2000 ◽  
Vol 203 (6) ◽  
pp. 1081-1092 ◽  
Author(s):  
R.S. Simons ◽  
W.O. Bennett ◽  
E.L. Brainerd

The mechanics of lung ventilation in frogs and aquatic salamanders has been well characterized, whereas lung ventilation in terrestrial-phase (post-metamorphic) salamanders has received little attention. We used electromyography (EMG), X-ray videography, standard videography and buccal and body cavity pressure measurements to characterize the ventilation mechanics of adult (post-metamorphic) tiger salamanders (Ambystoma tigrinum). Three results emerged: (i) under terrestrial conditions or when floating at the surface of the water, adult A. tigrinum breathed through their nares using a two-stroke buccal pump; (ii) in addition to this narial two-stroke pump, adult tiger salamanders also gulped air in through their mouths using a modified two-stroke buccal pump when in an aquatic environment; and (iii) exhalation in adult tiger salamanders is active during aquatic gulping breaths, whereas exhalation appears to be passive during terrestrial breathing at rest. Active exhalation in aquatic breaths is indicated by an increase in body cavity pressure during exhalation and associated EMG activity in the lateral hypaxial musculature, particularly the M. transversus abdominis. In terrestrial breathing, no EMG activity in the lateral hypaxial muscles is generally present, and body cavity pressure decreases during exhalation. In aquatic breaths, tidal volume is larger than in terrestrial breaths, and breathing frequency is much lower (approximately 1 breath 10 min(−)(1)versus 4–6 breaths min(−)(1)). The use of hypaxial muscles to power active exhalation in the aquatic environment may result from the need for more complete exhalation and larger tidal volumes when breathing infrequently. This hypothesis is supported by previous findings that terrestrial frogs ventilate their lungs with small tidal volumes and exhale passively, whereas aquatic frogs and salamanders use large tidal volumes and and exhale actively.


2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Xiaofeng Chen ◽  
Zhuohui Gan ◽  
Wuchao Tian ◽  
Yongkai Lv

Objective: To evaluate the effects of rehabilitation training of core muscle stability on stroke patients with hemiplegia. Methods: A total of 180 stroke patients who were hospitalized from December 2017 to December 2018 were enrolled. They were randomly divided into an observation group and a control group (n=90) that both received conventional hemiplegia rehabilitation therapy. On this basis, the observation group was subjected to training for core muscle stability, five times a week for a total of eight weeks. The balance functions before and after training were assessed using the Berg Balance Scale (BBS). The functions of hemiplegic lower limbs were evaluated by Brunnstrom staging and the Fugl-Meyer motor assessment (FMA) scale. The walking speed was estimated using the 10 m walking test. Musculoskeletal ultrasonography was performed to measure the thicknesses of three abdominal muscles of the paralytic side, i.e. transverse abdominis, internal oblique and external oblique muscles. Results: After treatment, the BBS scores of the two groups were significantly higher than those before treatment, with significant differences (P<0.05). The BBS score of the observation group was significantly higher than that of the control group (P<0.05). After treatment, the Brunnstrom stage and FMA scale score, and standing and stepping scores were significantly higher than those before treatment (P<0.05). The Brunnstrom stage, FMA scale score, stepping score and walking speed of the observation group significantly exceeded those of the control group (P<0.05). After treatment, the thicknesses all increased compared with those before treatment, but the thicknesses of internal oblique and external oblique muscles were not significantly different (P>0.05). The thickness of transverse abdominis muscle of the observation group significantly surpassed that before treatment (P<0.05), whereas the thicknesses of the control group were similar (P>0.05). The thickness of transverse abdominis muscle of the observation group was significantly higher than that of the control group (P<0.05). Conclusion: Rehabilitation training of core muscle stability can effectively improve the balance function and walking speed of stroke patients, probably by increasing the thickness of transverse abdominis muscle. doi: https://doi.org/10.12669/pjms.36.3.1466 How to cite this:Chen X, Gan Z, Tian W, Lv Y. Effects of rehabilitation training of core muscle stability on stroke patients with hemiplegia. Pak J Med Sci. 2020;36(3):---------. doi: https://doi.org/10.12669/pjms.36.3.1466 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Medicina ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 129
Author(s):  
Jung Won Kwon ◽  
Seo Yoon Park ◽  
Ki Hyun Baek ◽  
Kyoungsoo Youk ◽  
Seunghue Oh

Background and objectives: The maximal abdominal contraction maneuver (MACM) was designed as an effective and efficient breathing exercise to increase the stability of the spinal joint. However, it has not been determined whether MACM is more effective and efficient than the maximal expiration method. Thus, the present study was undertaken to investigate whole abdominal muscle thickness changes after MACM. Materials and Methods: Thirty healthy subjects (17 males and 13 females) participated in this study. An experimental comparison between MACM and the maximal expiration task was conducted by measuring the change of abdominal muscle thickness such as the transverse abdominis (TrA), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) using ultrasound images. Results: The results indicated that MACM resulted in significantly greater muscle thickness increases of the TrA and RA than the maximal expiration exercise (p < 0.05). Conclusion: MACM provided better exercise than the maximal expiration exercise in terms of increasing spine stability, at least from a co-contraction perspective.


2021 ◽  
Vol 21 (87) ◽  
pp. 286-293
Author(s):  
Hamid Zamani ◽  
Mahdi Dadgoo ◽  
Mohammad Akbari ◽  
Javier Fernández-Jara ◽  
Mohammadreza Pourahmadi

Aim: To examine the reliability of rehabilitative ultrasound imaging performed to measure the thickness of the transverse abdominis, internal oblique, external oblique, and lumbar multifidus muscles in females with recurrent low back pain. Material and methods: A sample of 15 women was recruited. Two independent examiners recorded the thickness of their deep abdominal and spinal muscles by rehabilitative ultrasound imaging. Imaging scans of the transverse abdominis, internal oblique, and external oblique muscles were performed in the supine position and in the midaxillary line, between the lower edge of the ribcage and the iliac crest. Imaging of the lumbar multifidus was done in the prone position and at the level of the L5/S1 zygapophyseal joints. Imaging scans were performed bilaterally in rest and contraction, three times by the first examiner (at baseline, after two hours, and one week later) and once by the second examiner. Results: Good to excellent within-session intra-rater (ICC = 0.76, 0.97), good to excellent between-session intra-rater reliability (ICC = 0.73, 0.93), and good to excellent inter-rater reliability (ICC = 0.73, 0.98) were obtained. Conclusions: The results showed that rehabilitative ultrasound imaging can be used as an excellent reliable instrument by one or two examiners to measure the thickness of the transverse abdominis, internal oblique, external oblique and lumbar multifidus muscles in females with recurrent low back pain.


1976 ◽  
Vol 54 (8) ◽  
pp. 1364-1374 ◽  
Author(s):  
D. H. Macintyre ◽  
D. P. Toews

Respiratory and circulatory changes associated with exposure to elevated ambient carbon dioxide (CO2) levels were studied in free-moving Bufo marinus. The buccal cavity, lungs, and systemic arch were cannulated singly or in various combinations. Simultaneous recordings from the lungs and buccal cavity permitted analysis of respiratory rate and pattern, while systemic cannulae provided constant blood-pressure measurements. All experiments were conducted at 22 °C.Normal breathing patterns consisted of continuous buccal 'oscillations' with irregularly occurring lung 'ventilations' and occasional high pressure 'inflations.' On exposure to increased ambient CO2 levels, oscillations decreased, ventilations increased, and inflations predominated, resulting in an overall increase in lung minute-volume. Systemic pressure decreased as ambient CO2 approached 3%, but returned to normal, with an associated increase in heart rate, at the 5% level. It is postulated that the ventilatory and concomitant circulatory responses are mediated by receptors functioning in both the chemoreceptive and baroreceptive modes.


Genome ◽  
2013 ◽  
Vol 56 (7) ◽  
pp. 407-414 ◽  
Author(s):  
Jacqueline M. Doyle ◽  
Gregor Siegmund ◽  
Joseph D. Ruhl ◽  
Soo Hyung Eo ◽  
Matthew C. Hale ◽  
...  

Historically, many population genetics studies have utilized microsatellite markers sampled at random from the genome and presumed to be selectively neutral. Recent studies, however, have shown that microsatellites can occur in transcribed regions, where they are more likely to be under selection. In this study, we mined microsatellites from transcriptomes generated by 454-pyrosequencing for three vertebrate species: lake sturgeon (Acipenser fulvescens), tiger salamander (Ambystoma tigrinum), and kangaroo rat (Dipodomys spectabilis). We evaluated (i) the occurrence of microsatellites across species; (ii) whether particular gene ontology terms were over-represented in genes that contained microsatellites; (iii) whether repeat motifs were located in untranslated regions or coding sequences of genes; and (iv) in silico polymorphism. Microsatellites were less common in tiger salamanders than in either lake sturgeon or kangaroo rats. Across libraries, trinucleotides were found more frequently than any other motif type, presumably because they do not cause frameshift mutations. By evaluating variation across reads assembled to a given contig, we were able to identify repeat motifs likely to be polymorphic. Our study represents one of the first comparative data sets on the distribution of vertebrate microsatellites within expressed genes. Our results reinforce the idea that microsatellites do not always occur in noncoding DNA, but commonly occur in expressed genes.


1987 ◽  
Vol 62 (6) ◽  
pp. 2314-2319 ◽  
Author(s):  
J. S. Arnold ◽  
A. J. Thomas ◽  
S. G. Kelsen

The present study examined the intrinsic contractile properties and endurance of the transverse abdominis and external oblique abdominal expiratory muscles in adult hamsters and compared their performance with the diaphragm. Experiments were performed in vitro on isolated bundles of muscle stimulated electrically. In control animals peak twitch tension was similar in the two muscles. In contrast, the twitch contraction time and one-half relaxation time of the transverse abdominis were significantly greater than that of the external oblique. The isometric tension generated over a range of stimulus frequencies (i.e., the force-frequency relationship) was a greater percent of the maximum value in response to subtetanizing frequencies (10–40 Hz) in the transverse abdominis than in the external oblique. For both abdominal muscles, however, the tension generated over this range of stimulus frequencies was less than that of the diaphragm. The endurance of the transverse abdominis during repeated contractions was significantly greater than that of the external oblique but similar to the diaphragm. The effect of chronic hyperinflation produced by elastase-induced emphysema on the contractile function of the two muscles was assessed in a second group of adult hamsters. In emphysematous animals peak twitch tension, contraction time, and one-half relaxation time of the twitch and force-frequency curves of muscles from emphysematous animals were similar to values obtained in control animals for both the external oblique and transverse abdominis. However, the endurance of both the transverse abdominis and external oblique muscles was greater in emphysematous than control animals.(ABSTRACT TRUNCATED AT 250 WORDS)


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