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Advances in Physiology Education Dec 2003Exercise offers a unique stage from which to study and teach the integration of physiological systems. In this article, the process of matching O(2) transport from air... (Review)
Review
Exercise offers a unique stage from which to study and teach the integration of physiological systems. In this article, the process of matching O(2) transport from air to its ultimate consumption in the contracting cell is utilized to integrate the workings of the cardiac, smooth, and skeletal muscle systems. Specifically, the physiology of exercise and the maximal oxygen consumption (V(.)O(2 max)) achieved through the precise linking of these three muscle systems are utilized to highlight the complexity and importance of this integration. Smooth muscle plays a vital "middleman" role in the distribution of blood-borne O(2) to the appropriate area of demand. Cardiac muscle instigates the convective movement of this O(2), whereas skeletal muscle acts as the recipient and ultimate consumer of O(2) in the synthesis of ATP and performance of work. In combination, these muscle systems facilitate the remarkable 15- to 30-fold increase in metabolic rate from rest to maximal effort in endurance-type exercise.
Topics: Animals; Biological Transport; Exercise; Humans; Muscle, Skeletal; Muscle, Smooth; Muscles; Myocardium; Oxygen; Papillary Muscles; Regional Blood Flow
PubMed: 14627616
DOI: 10.1152/advan.00038.2003 -
Folia Morphologica 2023Knowledge of anatomical variations can be of use to clinicians and surgeons when, for example, viewing images of a patient or performing operations. Such knowledge can... (Review)
Review
Knowledge of anatomical variations can be of use to clinicians and surgeons when, for example, viewing images of a patient or performing operations. Such knowledge can minimise the risk of iatrogenic complications. Herein, we present a case of a variant atlantomastoid muscle. The muscle was identified on the left side in an adult cadaver. The muscle's measurements and anatomical relationships are presented as well as a review of salient literature. We hope that increased knowledge of anatomical variants in the suboccipital region can improve patient care.
Topics: Adult; Humans; Muscle, Skeletal; Cadaver; Anatomic Variation; Surgeons
PubMed: 34826133
DOI: 10.5603/FM.a2021.0126 -
Journal of Biomedicine & Biotechnology 2010
Topics: Animals; Humans; Muscle Contraction; Muscles
PubMed: 20798778
DOI: 10.1155/2010/780417 -
Journal of Visualized Experiments : JoVE Apr 2020Electromyography (EMG) measures the muscle response to electrical stimulation or spontaneous activity of motor units and plays an important role in assessing...
Electromyography (EMG) measures the muscle response to electrical stimulation or spontaneous activity of motor units and plays an important role in assessing neuromuscular function. Chronic recording of EMG activity reflecting a muscle's reinnervation status after nerve injury has been limited, due to the invasive nature of traditional EMG recording techniques. In this regard, an implantable system is designed for long-term, in vivo EMG recording and nerve stimulation. It has been applied and tested in a study on reinnervation of laryngeal muscles. This system consists of 1) two bipolar electrode nerve cuffs and leads for stimulating each of two nerves: the recurrent laryngeal nerve (RLN) and internal branch of the superior laryngeal nerve (SLN); 2) two EMG recording electrodes and leads for each of the two laryngeal muscles: posterior cricoarytenoid (PCA) muscle and thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex; and 3) a skin receptacle interfacing all implanted lead terminals to an external recording preamplifier and stimulator using a connection cable. The wire leads are Teflon-coated, multi-filament, type 316 stainless steel. They are coiled and can stretch during body movement of the awake animal to prevent lead breakage and electrode migration. This system is implanted during an aseptic surgery. Afterwards, baseline EMG recordings are performed before the RLN is transected in the second surgery to study muscle reinnervation. Throughout the study, multiple physiological sessions are conducted in the anesthetized animal to obtain evoked and spontaneous EMG activity that reflects the reinnervation status of laryngeal muscles. The system is compact, free of infection over the course of the study, and highly durable. This implantable system can provide a reliable platform for research in which long-term recording or nerve stimulation is required in an anesthetized or freely moving animal.
Topics: Animals; Electric Stimulation; Electrodes, Implanted; Electromyography; Laryngeal Muscles; Neuromuscular Monitoring; Prostheses and Implants; Recurrent Laryngeal Nerve
PubMed: 32391811
DOI: 10.3791/60345 -
Journal of Biomechanics May 2021This study aimed to identify characteristics of the triceps surae muscles and aponeuroses stiffness in vivo, during graded isometric submaximal plantarflexion efforts. A...
This study aimed to identify characteristics of the triceps surae muscles and aponeuroses stiffness in vivo, during graded isometric submaximal plantarflexion efforts. A total of twelve healthy male subjects (age: 27 ± 4 years) participated and were required to stay at rest (0% MVC) and perform isometric submaximal plantar flexion contractions (20%, 40%, 60% of MVC) on a dynamometer. Young's modulus of triceps surae muscles and the adjoining aponeuroses between gastrocnemii and soleus at the proximal and distal sites were obtained in the longitudinal direction (along muscle's line of action) during at rest and submaximal plantar flexions. Additionally, Young's modulus of adjoining aponeuroses in the transverse direction at the distal sites was also calculated. Young's modulus of LG (lateral gastrocnemius), SOL-lat (lateral part of soleus) and LPS (superficial aponeurosis of LG) at the proximal site showed significant (p < 0.001) graded increase response to the submaximal contraction levels. Besides, in the lateral side, significant differences in the Young's modulus of aponeuroses were observed between longitudinal and transverse directions at rest and during contractions (p < 0.002). Changes of aponeuroses length were significantly correlated with Young's modulus changes of the proximal gastrocnemii muscle bellies (r = 0.43-0.45, p = 0.006-0.008) and superficial aponeuroses (r = 0.49-0.60, p < 0.002). The results further indicate that the triceps surae muscles and aponeuroses showed inhomogeneous and anisotropic mechanical properties during submaximal muscle contractions, and the stiffening effect of muscle belly possibly make influence on the mechanical properties of aponeuroses during muscle contractions, especially for the lateral gastrocnemius.
Topics: Adult; Aponeurosis; Humans; Isometric Contraction; Leg; Male; Muscle Contraction; Muscle, Skeletal; Young Adult
PubMed: 33836425
DOI: 10.1016/j.jbiomech.2021.110396 -
Scientific Reports May 2023We investigated the coordinated activity patterns of muscles based on cosine tuning in the elderly during an isometric force exertion task. We also clarified whether...
We investigated the coordinated activity patterns of muscles based on cosine tuning in the elderly during an isometric force exertion task. We also clarified whether these coordinated activity patterns contribute to the control of hip and knee joint torque and endpoint force as co-activation. Preferred direction (PD) of activity for each muscle in 10 young and 8 older males was calculated from the lower limb muscle activity during isometric force exertion task in various directions. The covariance of endpoint force (η) was calculated from the exerted force data using a force sensor. Relationship between PD and η was used to examine the effect of muscle co-activation on the control of endpoint force. Co-activation between rectus femoris and semitendinosus/biceps femoris increased with changes in muscle PD. Additionally, the η values were significantly low, suggesting that co-activation of multiple muscles may contribute to endpoint force exertion. The mechanism for cooperative muscle activity is determined by the cosine tuning of the PD of each muscle, which affects the generation of hip and knee joint torque and endpoint force exertion. Co-activation of each muscle's PD changes with age, causing increased muscle co-activation to control torque and force. We demonstrated that co-activation in the elderly is a stabilizer of unsteady joints and a muscle control strategy for cooperative muscle activity.
Topics: Male; Humans; Aged; Torque; Knee Joint; Lower Extremity; Quadriceps Muscle; Hamstring Muscles; Muscle, Skeletal; Electromyography; Isometric Contraction; Hip Joint
PubMed: 37130954
DOI: 10.1038/s41598-023-34208-6 -
Journal of Biomechanics Oct 2018In musculoskeletal models of the human temporomandibular joint (TMJ), muscles are typically represented by force vectors that connect approximate muscle origin and...
In musculoskeletal models of the human temporomandibular joint (TMJ), muscles are typically represented by force vectors that connect approximate muscle origin and insertion centroids (centroid-to-centroid force vectors). This simplification assumes equivalent moment arms and muscle lengths for all fibers within a muscle even with complex geometry and may result in inaccurate estimations of muscle force and joint loading. The objectives of this study were to quantify the three-dimensional (3D) human TMJ muscle attachment morphometry and examine its impact on TMJ mechanics. 3D muscle attachment surfaces of temporalis, masseter, lateral pterygoid, and medial pterygoid muscles of human cadaveric heads were generated by co-registering measured attachment boundaries with underlying skull models created from cone-beam computerized tomography (CBCT) images. A bounding box technique was used to quantify 3D muscle attachment size, shape, location, and orientation. Musculoskeletal models of the mandible were then developed and validated to assess the impact of 3D muscle attachment morphometry on joint loading during jaw maximal open-close. The 3D morphometry revealed that muscle lengths and moment arms of temporalis and masseter muscles varied substantially among muscle fibers. The values calculated from the centroid-to-centroid model were significantly different from those calculated using the 'Distributed model', which considered crucial 3D muscle attachment morphometry. Consequently, joint loading was underestimated by more than 50% in the centroid-to-centroid model. Therefore, it is necessary to consider 3D muscle attachment morphometry, especially for muscles with broad attachments, in TMJ musculoskeletal models to precisely quantify the joint mechanical environment critical for understanding TMJ function and mechanobiology.
Topics: Aged; Cone-Beam Computed Tomography; Humans; Imaging, Three-Dimensional; Male; Models, Biological; Muscles; Temporomandibular Joint
PubMed: 30166225
DOI: 10.1016/j.jbiomech.2018.08.010 -
Folia Medica Cracoviensia Apr 2023Temporomandibular disorder (TMD) is a disease of multifactorial etiology and a complex of symptoms, related to disorders of the masticatory muscles, temporomandibular... (Review)
Review
Temporomandibular disorder (TMD) is a disease of multifactorial etiology and a complex of symptoms, related to disorders of the masticatory muscles, temporomandibular joints and the surrounding orofacial structures. One of the main problems in the course of TMD disorders is the systematic increase in the tension of the masticatory muscles (masseter muscles, temporalis and medial and lateral pterygoid muscles), what is the cause of many damages and the development of pathological conditions in the stomatognathic system. The article discusses the differences in the structure of the masticatory and skeletal muscles, as well as the different nature and isoforms of myosin, which determines the much faster generation of contraction in the masticatory muscles and consequently easier generation of excessive, harmful tensions in the masticatory muscles. The article describes the causes of increased tension in the masticatory muscles and methods of their relaxation used in the basic and supportive treatment of temporomandibular disorders. The use of occlusal splints, physiotherapeutic procedures and TMD treatment with botulinum toxin type A were characterized. A role of psychological support and the methods used for patients with TMD were emphasized.
Topics: Humans; Temporomandibular Joint Disorders; Masticatory Muscles; Masseter Muscle; Temporomandibular Joint; Occlusal Splints
PubMed: 37406276
DOI: 10.24425/fmc.2023.145429 -
Integrative and Comparative Biology Dec 2014We review here the use and reliability of Hill-type muscle models to predict muscle performance under varying conditions, ranging from in situ production of isometric... (Review)
Review
We review here the use and reliability of Hill-type muscle models to predict muscle performance under varying conditions, ranging from in situ production of isometric force to in vivo dynamics of muscle length change and force in response to activation. Muscle models are frequently used in musculoskeletal simulations of movement, particularly when applied to studies of human motor performance in which surgically implanted transducers have limited use. Musculoskeletal simulations of different animal species also are being developed to evaluate comparative and evolutionary aspects of locomotor performance. However, such models are rarely validated against direct measures of fascicle strain or recordings of muscle-tendon force. Historically, Hill-type models simplify properties of whole muscle by scaling salient properties of single fibers to whole muscles, typically accounting for a muscle's architecture and series elasticity. Activation of the model's single contractile element (assigned the properties of homogenous fibers) is also simplified and is often based on temporal features of myoelectric (EMG) activation recorded from the muscle. Comparison of standard one-element models with a novel two-element model and with in situ and in vivo measures of EMG, fascicle strain, and force recorded from the gastrocnemius muscles of goats shows that a two-element Hill-type model, which allows independent recruitment of slow and fast units, better predicts temporal patterns of in situ and in vivo force. Recruitment patterns of slow/fast units based on wavelet decomposition of EMG activity in frequency-time space are generally correlated with the intensity spectra of the EMG signals, the strain rates of the fascicles, and the muscle-tendon forces measured in vivo, with faster units linked to greater strain rates and to more rapid forces. Using direct measures of muscle performance to further test Hill-type models, whether traditional or more complex, remains critical for establishing their accuracy and essential for verifying their applicability to scientific and clinical studies of musculoskeletal function.
Topics: Animals; Biomechanical Phenomena; Computer Simulation; Electromyography; Female; Goats; Isometric Contraction; Isotonic Contraction; Locomotion; Male; Models, Biological; Muscle, Skeletal; Principal Component Analysis
PubMed: 24928073
DOI: 10.1093/icb/icu070 -
Clinics (Sao Paulo, Brazil) 2020To verify the pyramidalis muscle's frequency (bilaterality, unilaterality, or absence) and morphometry (length of the medial border and width of its origin/base) in a...
OBJECTIVES
To verify the pyramidalis muscle's frequency (bilaterality, unilaterality, or absence) and morphometry (length of the medial border and width of its origin/base) in a sample of the Brazilian population and the anthropometric influence.
METHODS
Dissection of 30 cadavers, up to 24h post-mortem.
RESULTS
The pyramidalis muscle was present bilaterally and unilaterally in 83.33% and 3.33% of the cadavers, respectively, and absent in 13.33%. The muscles on the right and left sides were symmetrical in length but not in width; the pyramidalis muscles of men were longer, while those of the women were wider. We also found that there was greater variation in the dimensions (length and width) of the men's muscles. Finally, in this sample of the Brazilian population, the pyramidalis muscle's unilaterality was more prevalent than in other populations, and its complete absence was less prevalent.
CONCLUSIONS
There were no cases of muscle duplication in one or both sides, as described in some studies. Despite all of its morphometric variation, the pyramidalis muscle maintained its triangular shape with longitudinal fibers in every case. Furthermore, no statistically significant correlation was noted between the muscles' dimensions and person's age, height, weight, or gender.
Topics: Abdominal Muscles; Adult; Brazil; Cadaver; Female; Humans; Male
PubMed: 32667491
DOI: 10.6061/clinics/2020/e1623