Muscle Contraction
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Characterization of Cecal Smooth Muscle Contraction in Laying Hens
veterinary sciences Communication Characterization of Cecal Smooth Muscle Contraction in Laying Hens Katrin Röhm 1, Martin Diener 2 , Korinna Huber 1 and Jana Seifert 1,* 1 Institute of Animal Science, University of Hohenheim, 70593 Stuttgart, Germany; [email protected] (K.R.); [email protected] (K.H.) 2 Institute of Veterinary Physiology and Biochemistry, Justus-Liebig University, 35392 Gießen, Germany; [email protected] * Correspondence: [email protected] Abstract: The ceca play an important role in the physiology of the gastrointestinal tract in chickens. Nevertheless, there is a gap of knowledge regarding the functionality of the ceca in poultry, especially with respect to physiological cecal smooth muscle contraction. The aim of the current study is the ex vivo characterization of cecal smooth muscle contraction in laying hens. Muscle strips of circular cecal smooth muscle from eleven hens are prepared to investigate their contraction ex vivo. Contraction is detected using an isometric force transducer, determining its frequency, height and intensity. Spontaneous contraction of the chicken cecal smooth muscle and the influence of buffers (calcium-free buffer and potassium-enriched buffer) and drugs (carbachol, nitroprusside, isoprenaline and Verapamil) affecting smooth muscle contraction at different levels are characterized. A decrease in smooth muscle contraction is observed when a calcium-free buffer is used. Carbachol causes an increase in smooth muscle contraction, whereas atropine inhibits contraction. Nitroprusside, isoprenaline and Verapamil result in a depression of smooth muscle contraction. In conclusion, the present results confirm a similar contraction behavior of cecal smooth muscles in laying hens as Citation: Röhm, K.; Diener, M.; shown previously in other species. -
Skeletal Muscle Physiology
This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Skeletal Muscle Physiology First of all, which muscle is which - Skeletal muscle: o Well-developed cross-striations o Does not contract in absence of a nerve stimulus o The individual muscle fibers DO NOT connect functionally or anatomically (i.e. they don’t form a single sheet of cells, and one fiber’s action potential wont get transmitted to the next) o Generally, skeletal muscle is under voluntary control - Cardiac muscle: o Also has cross-striations o Is functionally syncytial: cells are connected well enough to conduct action potentials to one another o Can contract on its own, without stimulus (but this is under some control via the autonomic nervous system, which modulates its activity) - Smooth muscle: o Has no cross-striations o Two broad types: . VISCERAL or “unitary” smooth muscle: Functionally syncytial, action potentials propagate from cell to cell Contains pacemakers which discharge irregularly, but remains under control of the autonomic nervous system Found in most hollow viscera . MULTI-UNIT SMOOTH MUSCLE Found in the eye and some other locations Does NOT activate spontaneously SKELETAL MUSCLE ORGANIZATION - Each muscle is a bundle of fibers - Each fiber is a long, multinucleated single cell - Each fiber is surrounded by a SARCOLEMMA- the cell membrane - There are NO SYNCYTIAL BRIDGES between the cells. When one cell goes off, the others don’t follow. TRANSVERSE TUBULES: T-tubules, invaginations of SARCOLEMMA: the muscle cell membrane the sarcolemma, they form part of the T-system; the space inside is an extension of the extracellular space. -
Back-To-Basics: the Intricacies of Muscle Contraction
Back-to- MIOTA Basics: The CONFERENCE OCTOBER 11, Intricacies 2019 CHERI RAMIREZ, MS, of Muscle OTRL Contraction OBJECTIVES: 1.Review the anatomical structure of a skeletal muscle. 2.Review and understand the process and relationship between skeletal muscle contraction with the vital components of the nervous system, endocrine system, and skeletal system. 3.Review the basic similarities and differences between skeletal muscle tissue, smooth muscle tissue, and cardiac muscle tissue. 4.Review the names, locations, origins, and insertions of the skeletal muscles found in the human body. 5.Apply the information learned to enhance clinical practice and understanding of the intricacies and complexity of the skeletal muscle system. 6.Apply the information learned to further educate clients on the importance of skeletal muscle movement, posture, and coordination in the process of rehabilitation, healing, and functional return. 1. Epithelial Four Basic Tissue Categories 2. Muscle 3. Nervous 4. Connective A. Loose Connective B. Bone C. Cartilage D. Blood Introduction There are 3 types of muscle tissue in the muscular system: . Skeletal muscle: Attached to bones of skeleton. Voluntary. Striated. Tubular shape. Cardiac muscle: Makes up most of the wall of the heart. Involuntary. Striated with intercalated discs. Branched shape. Smooth muscle: Found in walls of internal organs and walls of vascular system. Involuntary. Non-striated. Spindle shape. 4 Structure of a Skeletal Muscle Skeletal Muscles: Skeletal muscles are composed of: • Skeletal muscle tissue • Nervous tissue • Blood • Connective tissues 5 Connective Tissue Coverings Connective tissue coverings over skeletal muscles: .Fascia .Tendons .Aponeuroses 6 Fascia: Definition: Layers of dense connective tissue that separates muscle from adjacent muscles, by surrounding each muscle belly. -
Structure of a Skeletal Muscle
STRUCTURE OF A SKELETAL MUSCLE Skeletal muscles are not made of muscle cells alone • Skeletal muscle contains blood vessels that supply muscle cells with oxygen and glucose, and remove wastes, and nerves that coordinate muscle contraction • 1 § Each individual muscle cell (fiber) is surrounded by the _____________ § Several muscle cells are bundled together into a _________ by the _____________ § All fascicles that make up a muscle are, in turn, enclosed by the _____________ § Interconnected connective tissues taper down and connect to tendons or other connective tissues; attach muscle to bone or other structure to be moved Figure 9.1 Position and structure of a skeletal muscle. 2 FUNCTIONS OF SKELETAL MUSCLES • Muscle contractions are involved in more than just movement of bones at a joint: § § Contraction of diaphragm muscle is a vital function associated with respiratory system § _________________ – sitting, standing, holding head upright § Skeletal muscles attached to facial skin allow for facial expression; muscles in throat assist with swallowing § Sphincters composed of skeletal muscle allow conscious control over opening and closing of body openings § Support of soft tissue – abdominal walls, pelvic floor 3 • Functional groups of muscles: generally takes cooperation of several individual muscles working as a group to perform a movement or action § __________________ provide most force for a given muscle action § _____________have opposite action of agonist; allows for modulation and control of agonist movement § _____________aid agonists by supplying supplemental force, minimizing unwanted movement, and by helping to stabilize joints § _____________also provide stabilizing force that anchors a bone; protection from injury due to unnecessary movements Figure 9.3 Functional groups of muscles. -
Muscle Physiology Dr
Muscle Physiology Dr. Ebneshahidi Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle Figure 9.2 (a) Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the muscular system . 1. Locomotion . 2. Vasoconstriction and vasodilatation- constriction and dilation of blood vessel Walls are the results of smooth muscle contraction. 3. Peristalsis – wavelike motion along the digestive tract is produced by the Smooth muscle. 4. Cardiac motion . 5. Posture maintenance- contraction of skeletal muscles maintains body posture and muscle tone. 6. Heat generation – about 75% of ATP energy used in muscle contraction is released as heat. Copyright. © 2004 Pearson Education, Inc., publishing as Benjamin Cummings . Striation: only present in skeletal and cardiac muscles. Absent in smooth muscle. Nucleus: smooth and cardiac muscles are uninculcated (one nucleus per cell), skeletal muscle is multinucleated (several nuclei per cell ). Transverse tubule ( T tubule ): well developed in skeletal and cardiac muscles to transport calcium. Absent in smooth muscle. Intercalated disk: specialized intercellular junction that only occurs in cardiac muscle. Control: skeletal muscle is always under voluntary control‚ with some exceptions ( the tongue and pili arrector muscles in the dermis). smooth and cardiac muscles are under involuntary control. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Innervation: motor unit . a) a motor nerve and a myofibril from a neuromuscular junction where gap (called synapse) occurs between the two structures. at the end of motor nerve‚ neurotransmitter (i.e. acetylcholine) is stored in synaptic vesicles which will release the neurotransmitter using exocytosis upon the stimulation of a nerve impulse. Across the synapse the surface the of myofibril contains receptors that can bind with the neurotransmitter. -
The Ubiquitin Proteasome System in Neuromuscular Disorders: Moving Beyond Movement
International Journal of Molecular Sciences Review The Ubiquitin Proteasome System in Neuromuscular Disorders: Moving Beyond Movement 1, , 2, 3,4 Sara Bachiller * y , Isabel M. Alonso-Bellido y , Luis Miguel Real , Eva María Pérez-Villegas 5 , José Luis Venero 2 , Tomas Deierborg 1 , José Ángel Armengol 5 and Rocío Ruiz 2 1 Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, Lund University, Sölvegatan 19, 221 84 Lund, Sweden; [email protected] 2 Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla/Instituto de Biomedicina de Sevilla-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Sevilla, Spain; [email protected] (I.M.A.-B.); [email protected] (J.L.V.); [email protected] (R.R.) 3 Unidad Clínica de Enfermedades Infecciosas, Hospital Universitario de Valme, 41014 Sevilla, Spain; [email protected] 4 Departamento de Especialidades Quirúrgicas, Bioquímica e Inmunología, Facultad de Medicina, 29071 Universidad de Málaga, Spain 5 Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, 41013 Sevilla, Spain; [email protected] (E.M.P.-V.); [email protected] (J.Á.A.) * Correspondence: [email protected] These authors contributed equally to the work. y Received: 14 July 2020; Accepted: 31 August 2020; Published: 3 September 2020 Abstract: Neuromuscular disorders (NMDs) affect 1 in 3000 people worldwide. There are more than 150 different types of NMDs, where the common feature is the loss of muscle strength. These disorders are classified according to their neuroanatomical location, as motor neuron diseases, peripheral nerve diseases, neuromuscular junction diseases, and muscle diseases. Over the years, numerous studies have pointed to protein homeostasis as a crucial factor in the development of these fatal diseases. -
Regional Heterogeneity in Muscle Fiber Strain: the Role of Fiber Architecture
UC Irvine UC Irvine Previously Published Works Title Regional heterogeneity in muscle fiber strain: the role of fiber architecture. Permalink https://escholarship.org/uc/item/125212ss Authors Azizi, E Deslauriers, Amber R Publication Date 2014 DOI 10.3389/fphys.2014.00303 Peer reviewed eScholarship.org Powered by the California Digital Library University of California PERSPECTIVE ARTICLE published: 12 August 2014 doi: 10.3389/fphys.2014.00303 Regional heterogeneity in muscle fiber strain: the role of fiber architecture E. Azizi* and Amber R. Deslauriers Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, USA Edited by: The force, mechanical work and power produced by muscle fibers are profoundly affected Emma F.Hodson-Tole, Manchester by the length changes they undergo during a contraction. These length changes are in turn Metropolitan University, UK affected by the spatial orientation of muscle fibers within a muscle (fiber architecture). Reviewed by: Therefore any heterogeneity in fiber architecture within a single muscle has the potential Boris Prilutsky, Georgia Institute of Technology, USA to cause spatial variation in fiber strain. Here we examine how the architectural variation Glen Lichtwark, The University of within a pennate muscle and within a fusiform muscle can result in regional fiber strain Queensland, Australia heterogeneity. We combine simple geometric models with empirical measures of fiber *Correspondence: strain to better understand the effect of architecture on fiber strain heterogeneity. We E. Azizi, Department of Ecology and show that variation in pennation angle throughout a muscle can result in differences in Evolutionary Biology, 321 Steinhaus Hall, University of California Irvine, fiber strain with higher strains being observed at lower angles of pennation. -
Ryanodine Receptor Cluster Size Sets the Tone in Cerebral Smooth Muscle
COMMENTARY Ryanodine receptor cluster size sets the tone in cerebral smooth muscle COMMENTARY Christian Soellera,1 + Ryanodine receptors (RyRs) are large intracellular Ca2 WT mdx channels that provide the molecular basis of the pro- K+ K+ higher BK + + + cess termed Ca2 -induced Ca2 release (1). Ca2 sig- activity naling through RyRs has been shown to be critical for CaC BK BK skeletal, cardiac, and smooth muscle physiology (2) as well as for neurons (3) and secretory cells like pancre- larger RyR atic beta cells. RyRs were first seen in the electron RyRs RyRs clusters microscope as ∼30-nm-size particles (4), and it had SMCs been known from EM studies that they form clusters, SR SR typically in the narrow “junctional” space between sar- colemma and sarcoplasmic reticulum (SR) membranes. + Due to the inherent positive feedback of Ca2 -induced + Ca2 release, the size and shape of RyR clusters are expected to affect their functional activity. Indeed, de- SMCs SMCs tailed mathematical modeling suggests that RyR cluster- cerebral artery ing is important for determining the excitability of RyR- + mediated Ca2 release (5, 6) and could, in principle, also + affect the amount of Ca2 released in microscopic re- 2+ lease events termed Ca sparks (7). The experimental myogenic tone study of RyR clustering has received a boost with the reduced advent of optical superresolution microscopy, which myogenic has made the assessment of RyR cluster size more acces- sible by using essentially standard immunolabeling pro- tone tocols. When first applied in cardiac muscle cells, this myogenic tone (%) tone myogenic approach revealed a broad, approximately exponential vessel pressure (%) tone myogenic vessel pressure RyR cluster size distribution (8), which had previously not Fig. -
Summation of Motor Unit Force in Passive and Active Muscle Thomas G
ARTICLE Summation of Motor Unit Force in Passive and Active Muscle Thomas G. Sandercock Department of Physiology, Northwestern University Medical School, Chicago, IL SANDERCOCK, T.G. Summation of motor unit force in passive and active muscle. Exerc. Sport Sci. Rev., Vol. 33, No. 2, pp. 76–83, 2005. Nonlinear summation of force has been observed between motor units. The complex structure of muscle suggests many reasons why this could happen. When large portions of the muscle are active, however, the nonlinearities are small, and generally explained by stretch of the common elasticity. This suggests that the type of nonlinearity observed between motor units may not be physiologically significant. Key Words: motor unit, summation, model, architecture, nonlinear INTRODUCTION the width of the length–tension curve will remain the same. This simple example suggests that the force from separate Because of the complex structure of muscle, the transmission motor units might sum linearly in a muscle with parallel of force from a single fiber to the action of the whole muscle fibers. is poorly understood. The force produced by the activation of two motor units, for example, can be more (superadditive) or less (subadditive) than the force exerted by the sum of the Force Transmission Within a Muscle two motor units when they are activated alone. There are many reasons why the force of motor units may not sum The actual structure of even the simplest muscle is more linearly. This review examines the theoretical expectations complex than the serial or parallel arrangements described and the experimental literature on the summation of motor above. -
Motor Unit Number Estimation: a Technology and Literature Review Clifton L
AANEM TECHNOLOGY REVIEW MOTOR UNIT NUMBER ESTIMATION: A TECHNOLOGY AND LITERATURE REVIEW CLIFTON L. GOOCH, MD,1 TIMOTHY J. DOHERTY, MD, PhD,2,3,4 K. MING CHAN, MD,5 MARK B. BROMBERG, MD, PhD,6 RICHARD A. LEWIS, MD,7 DAN W. STASHUK, PhD,8 MICHAEL J. BERGER, MD, PhD,9,10 MICHAEL T. ANDARY, MD,11 and JASPER R. DAUBE, MD12 1 Department of Neurology, University of South Florida, Tampa, Florida, USA 2 Department of Physical Medicine and Rehabilitation, University of Western Ontario, London, Ontario, Canada 3 Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada 4 Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada 5 Division of Physical Medicine and Rehabilitation/Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada 6 Department of Neurology, University of Utah, Salt Lake City, Utah, USA 7 Department of Neurology, Cedars-Sinai, Los Angeles, California USA 8 Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada 9 School of Kinesiology, University of Western Ontario, London, Ontario, Canada 10 Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada 11 College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA 12 Department of Neurology, Mayo Clinic, Rochester Minnesota, USA Accepted 27 August 2014 ABSTRACT: Introduction: Numerous methods for motor unit inception of modern neuromuscular physiology. number estimation (MUNE) have been developed. The objective of this article is to summarize and compare the major methods The first motor unit number estimation (MUNE) and the available data regarding their reproducibility, validity, appli- method evolved from routine motor nerve conduc- cation, refinement, and utility. -
Spinal Reflexes
Spinal Reflexes Lu Chen, Ph.D. MCB, UC Berkeley 1 Simple reflexes such as stretch reflex require coordinated contraction and relaxation of different muscle groups Categories of Muscle Based on Direction of Motion Flexors Æ reduce the angle of joints Extensors Æ increase the angle of joints Categories of Muscle Based on Movement Agonist Æmuscle that serves to move the joint in the same direction as the studied muscle Antagonist Æ muscle that moves the joint in the opposite direction 2 1 Muscle Spindles •Small encapsulated sensory receptors that have a Intrafusal muscle spindle-like shape and are located within the fibers fleshy part of the muscle •In parallel with the muscle fibers capsule •Does not contribute to the overall contractile Sensory force endings •Mechanoreceptors are activated by stretch of the central region Afferent axons •Due to stretch of the whole muscle Efferent axons (including intrafusal f.) •Due to contraction of the polar regions of Gamma motor the intrafusal fibers endings 3 Muscle Spindles Organization 2 kinds of intrafusal muscle fibers •Nuclear bag fibers (2-3) •Dynamic •Static •Nuclear chain fibers (~5) •Static 2 types of sensory fibers •Ia (primary) - central region of all intrafusal fibers •II (secondary) - adjacent to the central region of static nuclear bag fibers and nuclear chain fibers Intrafusal fibers stretched Sensory ending stretched, (loading the spindle) increase firing Muscle fibers lengthens Sensory ending stretched, (stretched) increase firing Spindle unloaded, Muscle fiber shortens decrease firing 4 2 Muscle Spindles Organization Gamma motor neurons innervate the intrafusal muscle fibers. Activation of Shortening of the polar regions gamma neurons of the intrafusal fibers Stretches the noncontractile Increase firing of the center regions sensory endings Therefore, the gamma motor neurons provide a mechanism for adjusting the sensitivity of the muscle spindles. -
Titin N2A Domain and Its Interactions at the Sarcomere
International Journal of Molecular Sciences Review Titin N2A Domain and Its Interactions at the Sarcomere Adeleye O. Adewale and Young-Hoon Ahn * Department of Chemistry, Wayne State University, Detroit, MI 48202, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-(313)-577-1384 Abstract: Titin is a giant protein in the sarcomere that plays an essential role in muscle contraction with actin and myosin filaments. However, its utility goes beyond mechanical functions, extending to versatile and complex roles in sarcomere organization and maintenance, passive force, mechanosens- ing, and signaling. Titin’s multiple functions are in part attributed to its large size and modular structures that interact with a myriad of protein partners. Among titin’s domains, the N2A element is one of titin’s unique segments that contributes to titin’s functions in compliance, contraction, structural stability, and signaling via protein–protein interactions with actin filament, chaperones, stress-sensing proteins, and proteases. Considering the significance of N2A, this review highlights structural conformations of N2A, its predisposition for protein–protein interactions, and its multiple interacting protein partners that allow the modulation of titin’s biological effects. Lastly, the nature of N2A for interactions with chaperones and proteases is included, presenting it as an important node that impacts titin’s structural and functional integrity. Keywords: titin; N2A domain; protein–protein interaction 1. Introduction Citation: Adewale, A.O.; Ahn, Y.-H. The complexity of striated muscle is defined by the intricate organization of its com- Titin N2A Domain and Its ponents [1]. The involuntary cardiac and voluntary skeletal muscles are the primary types Interactions at the Sarcomere.