Morphological observations of motor units connected in-series to Golgi tendon organs

1986 ◽  
Vol 55 (1) ◽  
pp. 147-162 ◽  
Author(s):  
J. M. Spielmann ◽  
E. K. Stauffer
Keyword(s):  
Discharge Rate ◽  
Muscle Fibers ◽  
Motor Units ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Golgi Tendon Organs ◽  
In Series ◽  
The Cross ◽  
Tendon Organs

The glycogen-depletion technique (17, 32) has been used to examine the functional and morphological relationships between single isolated motor units (MUs) and single isolated Golgi tendon organs (GTOs) that were excited by the MUs in the soleus muscle of the cat. All MUs whose twitch contraction generated a brisk discharge from the GTOs during the rising and plateau phase of force development had a muscle fiber attached specifically to the proximal end of the GTOs. A significant (P less than 0.05) linear relationship was found between GTO discharge rate and the cross-sectional area of the muscle fibers that connected to a receptor. This was true when the correlation was calculated between firing rate and 1) the cross-sectional area of the entire collection of muscle fibers that connected in series to the GTOs; and 2) for the cross-sectional areas of the individually depleted muscle fibers that inserted on the GTO sample. These findings support the notion that the most physiologically relevant input for GTOs arises from the MUs that are attached directly in-series with the receptor.

Maximal force as a function of anatomical features of motor units in the cat tibialis anterior

1987 ◽  
Vol 57 (6) ◽  
pp. 1730-1745 ◽  
Author(s):  
S. C. Bodine ◽  
R. R. Roy ◽  
E. Eldred ◽  
V. R. Edgerton
Keyword(s):  
Motor Unit ◽  
Tibialis Anterior ◽  
Periodic Acid ◽  
Muscle Fibers ◽  
Motor Units ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Periodic Acid Schiff ◽  
Cross Sectional ◽  
Single Motor Unit

In 11 tibialis anterior muscles of the cat, a single motor unit was characterized physiologically and subsequently depleted of its glycogen through repetitive stimulation of an isolated ventral root filament. Muscle cross sections were stained for glycogen using a periodic acid-Schiff reaction, and single-fiber optical densities were determined to identify those fibers belonging to the stimulated motor unit. Innervation ratios were determined by counting the total number of muscle fibers in a motor unit in sections taken through several levels of the muscle. The average innervation ratios for the fast, fatigueable (FF) and fast, fatigue-resistant (FR) units were similar. However, the slow units (S) contained 61% fewer fibers than the fast units (FF and FR). Muscle fibers belonging to S and FR units were similar in cross-sectional area, whereas fibers belonging to FF units were significantly larger than fibers belonging to either S or FR units. Additionally, muscle fibers innervated by a single motoneuron varied by two- to eightfold in cross-sectional area. Specific tensions, based on total cross-sectional area determined by summing the areas of all muscle fibers of each unit, showed a modest difference between fast and slow units, the means being 23.5 and 17.2 N X cm-2, respectively. Variations in maximum tension among units could be explained principally by innervation ratio, although fiber cross-sectional area and specific tension did contribute to differences between unit types.

Analysis of the Cross-Sectional Area of the Adductor Longus Tendon

2007 ◽  
Vol 35 (6) ◽  
pp. 996-999 ◽  
Author(s):  
Eric J. Strauss ◽  
Kirk Campbell ◽  
Joseph A. Bosco
Keyword(s):  
Cross Section ◽  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Sectional Anatomy ◽  
Longus Muscle ◽  
The Cross ◽  
Adductor Longus ◽  
Muscle Origin

Background Strain injury to the adductor longus muscle is a common cause of groin pain in athletes and generally occurs in the proximal portion of the muscle, near its origin from the anterior aspect of the pubis. The composition and cross-sectional anatomy of this muscle's origin has not been previously described. Hypothesis We hypothesize that the adductor longus muscle origin is composed mainly of muscle fibers and that the tendon composes only a small part of the cross section at the origin of the muscle. Study Design Descriptive laboratory study. Methods We harvested 42 adductor longus muscles from 28 cadavers and measured the cross-sectional dimensions of the tendon with microcalipers. Next, we determined the relative contributions of the tendon and muscle fibers to the cross-sectional anatomy of the muscle using optical scanning. These 2 sets of measurements were obtained at 3 locations: at the muscle origin and 1.0 and 2.0 cm distal to the origin. Results The average length and width of the tendon was 11.6 and 3.7 mm, respectively, at the origin. The average cross-sectional areas of the tendon were 49.3, 27.9, and 25.7 mm2 at points 0.0, 1.0, and 2.0 cm from its origin, respectively. The origin of the adductor longus muscle was composed of 37.9% tendon and 62.1% muscle tissue. At 1.0 cm from the origin, the percentage of tendon decreased to 34%. At 2.0 cm from the origin, the tendon composed 26.7% of the cross section. Conclusion The cross-sectional area of the tendon of the adductor longus muscle is relatively small. The muscle origin is composed predominantly of direct attachment of muscle fibers. Clinical Relevance Knowledge of the cross-sectional anatomy of the adductor longus muscle at its origin may help clinicians better understand the complex nature of injuries in this area.

Essential role of satellite cells in the growth of rat soleus muscle fibers

2008 ◽  
Vol 295 (2) ◽  
pp. C458-C467 ◽  
Author(s):  
Fuminori Kawano ◽  
Yoshiaki Takeno ◽  
Naoya Nakai ◽  
Yoko Higo ◽  
Masahiro Terada ◽  
...  
Keyword(s):  
Soleus Muscle ◽  
Satellite Cells ◽  
Essential Role ◽  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Morphological Properties ◽  
Sectional Area ◽  
Cross Sectional ◽  
Gravitational Loading ◽  
The Cross

Effects of gravitational loading or unloading on the growth-associated increase in the cross-sectional area and length of fibers, as well as the total fiber number, in soleus muscle were studied in rats. Furthermore, the roles of satellite cells and myonuclei in growth of these properties were also investigated. The hindlimb unloading by tail suspension was performed in newborn rats from postnatal day 4 to month 3 with or without 3-mo reloading. The morphological properties were measured in whole muscle and/or single fibers sampled from tendon to tendon. Growth-associated increases of soleus weight and fiber cross-sectional area in the unloaded group were ∼68% and 69% less than the age-matched controls. However, the increases of number and length of fibers were not influenced by unloading. Growth-related increases of the number of quiescent satellite cells and myonuclei were inhibited by unloading. And the growth-related decrease of mitotically active satellite cells, seen even in controls (20%, P > 0.05), was also stimulated (80%). The increase of myonuclei during 3-mo unloading was only 40 times vs. 92 times in controls. Inhibited increase of myonuclear number was not related to apoptosis. The size of myonuclear domain in the unloaded group was less and that of single nuclei, which was decreased by growth, was larger than controls. However, all of these parameters, inhibited by unloading, were increased toward the control levels generally by reloading. It is suggested that the satellite cell-related stimulation in response to gravitational loading plays an essential role in the cross-sectional growth of soleus muscle fibers.

scholarly journals Effect of Gonadal Hormones on the Cross-Sectional Area of Pubococcygeus Muscle Fibers in Male Rat

2008 ◽  
Vol 291 (5) ◽  
pp. 586-592 ◽  
Author(s):  
Mayvi Alvarado ◽  
Estela Cuevas ◽  
Miguel Lara-García ◽  
Miguel Camacho ◽  
Porfirio Carrillo ◽  
...  
Keyword(s):  
Muscle Fibers ◽  
Gonadal Hormones ◽  
Cross Sectional Area ◽  
Male Rat ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross

scholarly journals Hormonal Treatment Effects on the Cross-sectional Area of Pubococcygeus Muscle Fibers After Denervation and Castration in Male Rats

2017 ◽  
Vol 300 (7) ◽  
pp. 1327-1335
Author(s):  
Miguel Lara-García ◽  
Mayvi Alvarado ◽  
Estela Cuevas ◽  
Omar Lara-García ◽  
Dale R. Sengelaub ◽  
...  
Keyword(s):  
Treatment Effects ◽  
Muscle Fibers ◽  
Hormonal Treatment ◽  
Cross Sectional Area ◽  
Male Rats ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross

scholarly journals Denervation and Castration Effects on the Cross-Sectional Area of Pubococcygeus Muscle Fibers in Male Rats

2013 ◽  
Vol 296 (10) ◽  
pp. 1634-1639 ◽  
Author(s):  
Mayvi Alvarado ◽  
Miguel Lara-García ◽  
Estela Cuevas ◽  
Pere Berbel ◽  
Pablo Pacheco
Keyword(s):  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Male Rats ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross

scholarly journals Use of Immunofluorescence Technique to Perform a Quantitative Analysis of Masseter Muscle Fibers in Unilateral Posterior Crossbite: A Pilot Study

2021 ◽  
Vol 11 (12) ◽  
pp. 5350
Author(s):  
Giovanna Vermiglio ◽  
Mariagrazia Piancino ◽  
Michele Runci Anastasi ◽  
Giacomo Picciolo ◽  
Antonio Centofanti ◽  
...  
Keyword(s):  
Masseter Muscle ◽  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Posterior Crossbite ◽  
Affected Side ◽  
The Cross ◽  
And Control ◽  
Contralateral Muscle

Unilateral posterior crossbite is a type of malocclusion that involves morpho-functional characteristics of masticatory muscle, such as the masseter: electrophysiological data have shown that the affected side works less than the contralateral muscle, which shows a normal or increased activity, probably in order to compensate for the affected side. The aim of present work was to measure the diameter and the cross-sectional area of ipsilateral and contralateral muscle fibers to verify if hypertrophy and/or hypotrophy take place in this malocclusion. We used immunofluorescence pictures to measure, using ImageJ software, the diameter and the cross-sectional area of fibers from control and crossbite groups; after that, the data were processed to perform statistical analyses. Results show that the fiber diameters of contralateral muscle are larger than the diameters of ipsilateral and control fibers, and that this difference is statistically significant. No statistically significant difference was found between the fiber diameters of the ipsilateral and control muscles. All these data suggest that, during unilateral posterior crossbite, morphological changes take place in the contralateral masseter muscle, which undergoes hypertrophy, probably to compensate for the low activity of the affected muscle.

The Effects of Castration and Hormone Replacement on the Cross-Sectional Area of Pubococcygeus Muscle Fibers in the Female Rat

2011 ◽  
Vol 294 (7) ◽  
pp. 1242-1248 ◽  
Author(s):  
Miguel Lara-García ◽  
Mayvi Alvarado ◽  
Estela Cuevas ◽  
Albertina Cortés-sol ◽  
Andrés Domínguez ◽  
...  
Keyword(s):  
Hormone Replacement ◽  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Female Rat ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross

Coordination of electromechanical and metabolic properties of cat soleus motor units

1988 ◽  
Vol 255 (5) ◽  
pp. C684-C693 ◽  
Author(s):  
T. P. Martin ◽  
S. Bodine-Fowler ◽  
V. R. Edgerton
Keyword(s):  
Spinal Cord ◽  
Muscle Fibers ◽  
Motor Units ◽  
Cross Sectional Area ◽  
Spinal Cord Transection ◽  
Sectional Area ◽  
Cross Sectional ◽  
Physiological Properties ◽  
Metabolic Properties ◽  
Adult Cats

Motor units were studied in the soleus muscle of normal adult cats and adult cats that had undergone complete spinal cord transection approximately 4 mo earlier. Intracellular recording and stimulation techniques were used to study selected electrical properties of the motoneuron and isometric contractile properties of the muscle unit. Motor unit fibers were depleted of their glycogen through repetitive stimulation of the motoneuron and identified by a quantitative histochemical determination of glycogen. A sample of muscle fibers from the glycogen-depleted unit and from fibers not depleted of glycogen were analyzed for cross-sectional area, succinate dehydrogenase (SDH), alpha-glycerolphosphate dehydrogenase (GPD), and alkaline myofibrillar adenosine triphosphatase. It was observed that the fiber-to-fiber variability in cross-sectional area and SDH and GPD activity within units of normal and transected cats was significantly larger than that measured in repeated samples from a single fiber. Additionally, for each of these properties, the range found among fibers within a unit was similar to that found among nondepleted fibers of the same myosin type. The influence of spinal cord transection on some muscle fibers seemed to result in a metabolic shift from the generalized category of slow-oxidative toward fast-oxidative glycolytic. This shift in metabolic properties appeared to be coupled with a similar shift in the physiological properties of the muscle unit and motoneuron from slow to fast.

Sign in / Sign up

Export Citation Format

Share Document