The role of the fusimotor system with respect to the contribution of the diaphragm and the intercostal muscles to the respiratory tidal volume

1976 ◽  
Vol 366 (2-3) ◽  
pp. 107-114 ◽  
Author(s):  
H. Th. Folgering ◽  
F. D. J. Smolders ◽  
J. A. Bernards
Keyword(s):  
Tidal Volume ◽  
Intercostal Muscles ◽  
Fusimotor System

Inspiratory elevation of the ribs in the dog: primary role of the parasternals [published errata appear in J Appl Physiol 1991 Aug;71(2):following Table of Contents and 1991 Dec;71(6):following Author Index]

1991 ◽  
Vol 70 (4) ◽  
pp. 1447-1455 ◽  
Author(s):  
A. De Troyer
Keyword(s):  
Quantitative Analysis ◽  
Axial Displacement ◽  
The Other ◽  
Primary Role ◽  
Intercostal Muscles ◽  
The Third ◽  
Inspiratory Activity ◽  
Fourth Rib

To assess the relative contributions of the different groups of inspiratory intercostal muscles to the cranial motion of the ribs in the dog, we have measured the axial displacement of the fourth rib and recorded the electromyograms of the parasternal intercostal, external intercostal, and levator costae in the third interspace in 15 anesthetized animals breathing at rest. In eight animals, the parasternal intercostals were denervated in interspaces 1-5. This procedure caused a marked increase in the amount of external intercostal and levator costae inspiratory activity, and yet the inspiratory cranial motion of the rib was reduced by 55%. On the other hand, the external intercostals in interspaces 1-5 were sectioned in seven animals, and the reduction in the cranial rib motion was only 22%; the amount of parasternal and levator costae activity, however, was unchanged. When the parasternals in these animals were subsequently denervated, the levator costae inspiratory activity increased markedly, but the inspiratory cranial motion of the rib was abolished or reversed into an inspiratory caudal motion. These studies thus confirm that, in the dog breathing at rest, the parasternal intercostals have a larger role than the external intercostals and levator costae in causing the cranial motion of the ribs during inspiration. A quantitative analysis suggests that the parasternal contribution is approximately 80%.

Coordination between rib cage muscles and diaphragm during quiet breathing in humans

1984 ◽  
Vol 57 (3) ◽  
pp. 899-906 ◽  
Author(s):  
A. De Troyer ◽  
M. Estenne
Keyword(s):  
Tidal Volume ◽  
Marked Reduction ◽  
Emg Activity ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Inspiratory Activity ◽  
Normal Humans ◽  
Volume Range

The pattern of activation of the scalenes and the parasternal intercostal muscles was studied in relation to the pattern of rib cage and abdominal motion during various respiratory maneuvers in the tidal volume range in five normal humans. Electromyograms (EMG) of the scalenes and parasternal intercostals were recorded with bipolar needle electrodes, and changes in abdominal and rib cage displacement were measured using linearized magnetometers. The scalenes and parasternal intercostals were always active during quiet breathing, and their pattern of activation was identical; in both muscles the EMG activity usually started together with the beginning of inspiration, increased in intensity as inspiration proceeded, and persisted into the early part of expiration. In addition, like the parasternal activity the scalene inspiratory activity persisted until the tidal volume was trivial, increased during tidal inspirations performed with the rib cage alone, and was nearly abolished during diaphragmatic isovolume maneuvers. However, attempts to perform tidal inspiration with the diaphragm alone, while causing an increase in parasternal EMG activity, were associated with a marked reduction or a suppression of scalene EMG activity and a reduced substantially distorted rib cage expansion. In particular, the upper rib cage was then moving paradoxically.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the Fusimotor System in Locomotion

2002 ◽  
pp. 335-342 ◽  
Author(s):  
Peter Ellaway ◽  
Anthony Taylor ◽  
Rade Durbaba ◽  
Stephen Rawlinson
Keyword(s):  
Fusimotor System

scholarly journals Effects of tidal volume and respiratory frequency on lung lymph flow

2005 ◽  
Vol 99 (2) ◽  
pp. 556-563 ◽  
Author(s):  
David B. Pearse ◽  
Robert M. Searcy ◽  
Wayne Mitzner ◽  
Solbert Permutt ◽  
J. T. Sylvester
Keyword(s):  
Tidal Volume ◽  
Lymphatic Vessels ◽  
Lymph Flow ◽  
Edema Formation ◽  
Fluid Filtration ◽  
Induced Changes ◽  
Lung Lymph ◽  
Lung Lymph Flow

Ventilation (V̇) increases lung lymph flow (Q̇l), but the separate effects of tidal volume (Vt) and frequency (f) and the role of V̇-induced changes in edema formation are poorly understood. An isolated, in situ sheep lung preparation was used to examine these effects. In eight sheep with f = 10 min−1, results obtained during 30-min periods with Vt = 5 or 20 ml/kg were compared with values obtained during bracketed 30-min control periods (Vt = 12.5 ml/kg). Eight other sheep with constant Vt (12.5 ml/kg) were studied at f = 5 or 20 min−1 and compared with f = 10 min−1. Three additional groups of six sheep were perfused for 100 min with control V̇ (10 ml/kg, 10 min−1). Vt was then kept constant or changed to 20 or 3 ml/kg during a second 100-min period. Increases in Vt or f increased Q̇l and vice versa, without corresponding effects on the rate of edema formation. For the same change in V̇, changing Vt had a greater effect on Q̇l than changing f. The change in Q̇l caused by an increase in Vt was significantly greater after the accumulation of interstitial edema. The change in Q̇l caused by a sustained increase in Vt was transient and did not correlate with the rate of edema formation, suggesting that V̇ altered Q̇l through direct mechanical effects on edema-filled compartments and lymphatic vessels rather than through V̇-induced changes in fluid filtration.

Mechanical role of expiratory muscles during breathing in upright dogs

1988 ◽  
Vol 64 (3) ◽  
pp. 1060-1067 ◽  
Author(s):  
G. A. Farkas ◽  
R. E. Baer ◽  
M. Estenne ◽  
A. De Troyer
Keyword(s):  
Tidal Volume ◽  
Progressive Increase ◽  
Substantial Contribution ◽  
Postural Changes ◽  
Before And After ◽  
Cervical Vagotomy ◽  
Anesthetized Dogs ◽  
Expiratory Muscles ◽  
Spontaneously Breathing

To examine the mechanical effects of the abdominal and triangularis sterni expiratory recruitment that occurs when anesthetized dogs are tilted head up, we measured both before and after cervical vagotomy the end-expiratory length of the costal and crural diaphragmatic segments and the end-expiratory lung volume (FRC) in eight spontaneously breathing animals during postural changes from supine (0 degree) to 80 degrees head up. Tilting the animals from 0 degree to 80 degrees head up in both conditions was associated with a gradual decrease in end-expiratory costal and crural diaphragmatic length and with a progressive increase in FRC. All these changes, however, were considerably larger (P less than 0.005 or less) postvagotomy when the expiratory muscles were no longer recruited with tilting. Alterations in the elastic properties of the lung could not account for the effects of vagotomy on the postural changes. We conclude therefore that 1) by contracting during expiration, the canine expiratory muscles minimize the shortening of the diaphragm and the increase in FRC that the action of gravity would otherwise introduce, and 2) the end-expiratory diaphragmatic length and FRC in upright dogs are thus actively determined. The present data also indicate that by relaxing at end expiration, the expiratory muscles make a substantial contribution to tidal volume in upright dogs; in the 80 degrees head-up posture, this contribution would amount to approximately 60% of tidal volume.

Failure of tracheal distension to inhibit breathing in anesthetized dogs

1980 ◽  
Vol 48 (5) ◽  
pp. 794-798 ◽  
Author(s):  
T. C. Lloyd ◽  
J. A. Cooper
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Potential Role ◽  
Minute Volume ◽  
Abdominal Compression ◽  
Frequency Increase ◽  
Before And After ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing

Using anesthetized spontaneously breathing dogs, we compared the respiratory effects of tracheal distension with the effects of changes in lung volume before and after vagotomy. We used an endotracheal tube with a long cuff to distend the trachea to pressures of 10, 20, and 40 cmH2O. Lung volume increases were imposed by expiratory threshold loading, and volume was decreased by abdominal compression, both of which caused outward rib cage displacement. During expiratory loading, the tidal volume was unchanged but respiratory frequency and minute volume fell and an active expiratory effort appeared; whereas frequency and minute volume rose, but tidal volume fell during abdominal compression. Tracheal distension evoked no discernible change in breathing. Following vagotomy, tidal volume and minute volume fell, and frequency rose slightly, during expiratory loading but abdominal compression was without effect. After vagotomy, 40 cmH2O tracheal distension caused a slight frequency increase. We concluded that the potential role of tracheal deformation in the reflex control of breathing is insignificant in comparison with the other airways.

scholarly journals Manipulating plasma thyroid hormone levels at hatching alters development of endothermy and ventilation in Pekin duck (Anas platyrhynchos domestica)

2020 ◽  
Vol 223 (22) ◽  
pp. jeb237701
Author(s):  
Tushar S. Sirsat ◽  
Edward M. Dzialowski
Keyword(s):  
Thyroid Hormone ◽  
Tidal Volume ◽  
Developmental Trajectory ◽  
Pekin Duck ◽  
Thyroid Peroxidase ◽  
Hormone Levels ◽  
Ventilation Frequency ◽  
Thyroid Hormone Levels ◽  
And Control

ABSTRACTAt hatching in precocial birds, there are rapid physiological and metabolic phenotypic changes associated with attaining endothermy. During the transition to ex ovo life, thyroid hormone levels naturally increase, peaking at hatching, and then decline. To better understand the role of the natural increase in thyroid hormone at hatching in regulating the developmental trajectory of the Pekin duck's endothermic phenotype, we examined development of O2 consumption (V̇O2) and ventilation (frequency, tidal volume and minute ventilation) while inhibiting the developmental increase in thyroid hormones that occurs at hatching via administration of the thyroid-peroxidase inhibitor methimazole (MMI) or accelerating the developmental increase via triiodothyronine (T3) supplementation. Animals were dosed only on day 24 of a 28-day incubation period and studied on incubation day 25, during external pipping (EP) and 1 day post-hatching (dph). On day 25, there was an increase in V̇O2 in the hyperthyroid treatment compared with the other two treatments. During the EP stage, there was a significant effect of thyroid status on V̇O2, with hyperthyroid V̇O2 being highest and hypothyroid V̇O2 the lowest. By 1 dph, the supplemented T3 and control animals had similar V̇O2 responses to cooling with comparable thermal neutral zones followed by increased V̇O2. Hypothyroid 1 dph hatchlings had a lower resting V̇O2 that did not increase to the same extent as the supplemented T3 and control animals during cooling. During EP, inhibiting the rise in T3 resulted in embryos with lower ventilation frequency and tidal volume than control and supplemented T3 embryos. At 1 dph, ventilation frequency of all animals increased during cooling, but tidal volume only increased in supplemented T3 and control hatchlings. Our data support the role of the late incubation increase in T3 in regulating the systemic development of endothermic metabolic capacity and associated control of ventilation occurring at hatching of the Pekin duck.

Sign in / Sign up

Export Citation Format

Share Document