8 Anat 35 Micro Muscle

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Human Anatomy Unit 2 MICROSCOPIC SKELETAL MUSCLE ANATOMY In Anatomy Today Skeletal Muscle Tissue • Characteristics – Striated – Multinucleate – Voluntary (somatic) • Anatomy – Muscle • Myofiber • Myofibril • Myofilament Muscle Microanatomy • Multinucleate – Develop from the fusion of multiple myoblasts – Each myoblast has its own nuclues • Myofiber – Muscle fiber – Muscle cell • Myofibril – Tubes of contractile proteins • Myofilament – Contractile proteins Muscle Fiber • Sarcolemma – Membrane of muscle fiber – Electrically excitable – T-tubules • Sarcoplasm – Muscle cytoplasm • Sarcoplasmic reticulum – Modified smooth ER – Lateral sacs – Stores calcium (Ca2+) • Functional unit of skeletal muscle is the sarcomere Sarcomere Structure • Z line – Defines the sarcomere • A band – Length of thick filament • H band – Space between thin filaments within a sarcomere • I band – Space between thick filaments between sarcomeres • Thick filament • Thin filament • Elastic filament Thin Filament • 2 strands of actin molecules – Has binding sites for myosin • Tropomyosin – Covers binding sites on actin for myosin – Resting fiber • Troponin – Holds tropomyosin in place – Binds to calcium (Ca2+) Thick and Elastic Filament • Thick Filament – Myosin – Tail – Myosin head • Myosin Head – 2 binding sites • ADP + pi • Actin • Elastic filament – Titin – Achors myosin in place within sarcomere Muscle Contraction • Sliding filament theory • Myosin heads bind to actin – 6 thin filaments: 1 thick filament • Heads change conformation and pull the actin filaments across myosin molecule – Discontinuous pulling • Sarcomere shortens – Thick and thin filaments do not shorten! • All or none response Neuromuscular Junction • Somatic motor neuron innervates muscle fiber – Synaptic bulb – Vesicles – Acetylcholine (ACh) • Motor end plate – Invagination of sarcolemma – Receptors for ACh • 1:1 ratio Motor Unit • A single motor neuron and all of the muscle fibers it innervates • A somatic motor neuron has collateral branches that innervate multiple muscle fibers • When a motor neuron sends a signal to contract – All fibers in the motor unit will contract • A muscle will be comprised of multiple motor units – Ratio of motor units:muscle Skeletal Muscle Neuromuscular Junction Cardiac Muscle Smooth Muscle.

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Microanatomy of Muscles
Microanatomy of Muscles Anatomy & Physiology Class Three Main Muscle Types Objectives: By the end of this presentation you will have the information to: 1. Describe the 3 main types of muscles. 2. Detail the functions of the muscle system. 3. Correctly label the parts of a myocyte (muscle cell) 4. Identify the levels of organization in a skeletal muscle from organ to myosin. 5. Explain how a muscle contracts utilizing the correct terminology of the sliding filament theory. 6. Contrast and compare cardiac and smooth muscle with skeletal muscle. Major Functions: Muscle System 1. Moving the skeletal system and posture. 2. Passing food through the digestive system & constriction of other internal organs. 3. Production of body heat. 4. Pumping the blood throughout the body. 5. Communication - writing and verbal Specialized Cells (Myocytes) ~ Contractile Cells Can shorten along one or more planes because of specialized cell membrane (sarcolemma) and specialized cytoskeleton. Specialized Structures found in Myocytes Sarcolemma: The cell membrane of a muscle cell Transverse tubule: a tubular invagination of the sarcolemma of skeletal or cardiac muscle fibers that surrounds myofibrils; involved in transmitting the action potential from the sarcolemma to the interior of the myofibril. Sarcoplasmic Reticulum: The special type of smooth endoplasmic Myofibrils: reticulum found in smooth and a contractile fibril of skeletal muscle, composed striated muscle fibers whose function mainly of actin and myosin is to store and release calcium ions. Multiple Nuclei (skeletal) & many mitochondria Skeletal Muscle - Microscopic Anatomy A whole skeletal muscle (such as the biceps brachii) is considered an organ of the muscular system. Each organ consists of skeletal muscle tissue, connective tissue, nerve tissue, and blood or vascular tissue.
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The Myosin Interacting-Heads Motif Present in Live Tarantula Muscle Explains Tetanic and Posttetanic INAUGURAL ARTICLE Phosphorylation Mechanisms
The myosin interacting-heads motif present in live tarantula muscle explains tetanic and posttetanic INAUGURAL ARTICLE phosphorylation mechanisms Raúl Padróna,1,2, Weikang Mab,1, Sebastian Duno-Mirandac,3, Natalia Koubassovad, Kyoung Hwan Leea,4, Antonio Pintoc, Lorenzo Alamoc, Pura Bolañose, Andrey Tsaturyand, Thomas Irvingb, and Roger Craiga aDivision of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655; bBiophysics Collaborative Access Team, Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616; cCentro de Biología Estructural, Instituto Venezolano de Investigaciones Científicas, Caracas 1020A, Venezuela; dInstitute of Mechanics, Moscow State University, 119992 Moscow, Russia; and eCentro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas 1020A, Venezuela This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected in 2018. Contributed by Raúl Padrón, April 7, 2020 (sent for review December 6, 2019; reviewed by H. Lee Sweeney and Rene Vandenboom) Striated muscle contraction involves sliding of actin thin filaments frozen-hydrated tarantula thick filaments showed that the helices along myosin thick filaments, controlled by calcium through thin of heads on the filaments were formed by a two-headed assem- filament activation. In relaxed muscle, the two heads of myosin blage that we called the myosin interacting-heads motif (IHM) interact with each other on the filament surface to form the (8, 9), formed by the interaction of a blocked head (BH) and a interacting-heads motif (IHM). A key question is how both heads free head (FH) (10) with the subfragment-2 (8) (Fig.
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Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria
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Muscle Histology
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Removal of Abnormal Myofilament O-Glcnacylation Restores Ca
Diabetes Volume 64, October 2015 3573 Genaro A. Ramirez-Correa,1 Junfeng Ma,2 Chad Slawson,3 Quira Zeidan,2 Nahyr S. Lugo-Fagundo,1 Mingguo Xu,1 Xiaoxu Shen,4 Wei Dong Gao,4 Viviane Caceres,5 Khalid Chakir,5 Lauren DeVine,2 Robert N. Cole,2 Luigi Marchionni,6 Nazareno Paolocci,5 Gerald W. Hart,2 and Anne M. Murphy1 Removal of Abnormal Myofilament O-GlcNAcylation Restores Ca2+ Sensitivity in Diabetic Cardiac Muscle Diabetes 2015;64:3573–3587 | DOI: 10.2337/db14-1107 Contractile dysfunction and increased deposition of In diabetic cardiomyopathy, the contractile and electro- O-linked b-N-acetyl-D-glucosamine (O-GlcNAc) in car- physiological properties of the cardiac muscle are altered diac proteins are a hallmark of the diabetic heart. How- (1). Prior studies have mainly focused on alterations in ever, whether and how this posttranslational alteration Ca2+ handling (2–4). However, these perturbations alone contributes to lower cardiac function remains unclear. unlikely account for lower force production and altered COMPLICATIONS fi b Using a re ned -elimination/Michael addition with tan- relaxation typically found in the heart of patients with dem mass tags (TMT)–labeling proteomic technique, we diabetes (5,6). Indeed, the intrinsic properties of cardiac show that CpOGA, a bacterial analog of O-GlcNAcase myofilaments appear to be altered too (7,8). More specif- (OGA) that cleaves O-GlcNAc in vivo, removes site- 2+ 2+ fi specific O-GlcNAcylation from myofilaments, restoring ically, Ca sensitivity (ECa 50), a measure of myo la- 2+ Ca2+ sensitivity in streptozotocin (STZ) diabetic cardiac ment force production at near physiological Ca levels, – muscles.
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Carlson (7e) PowerPoint Lecture Outline Chapter 8: Control of Movement This multimedia product and its contents are protected under copyright law. The following are prohibited by law: •any public performance or display, including transmission of any image over a network; •preparation of any derivative work, including extraction, in whole or in part, of any images; •any rental, lease, or lending of the program. Copyright 2001 by Allyn & Bacon Skeletal Muscle n Movements of our body are accomplished by contraction of the skeletal muscles l Flexion: contraction of a flexor muscle draws in a limb l Extension: contraction of extensor muscle n Skeletal muscle fibers have a striated appearance n Skeletal muscle is composed of two fiber types: l Extrafusal: innervated by alpha-motoneurons from the spinal cord: exert force l Intrafusal: sensory fibers that detect stretch of the muscle u Afferent fibers: report length of intrafusal: when stretched, the fibers stimulate the alpha-neuron that innervates the muscle fiber: maintains muscle tone u Efferent fibers: contraction adjusts sensitivity of afferent fibers. 8.2 Copyright 2001 by Allyn & Bacon Skeletal Muscle Anatomy n Each muscle fiber consists of a bundle of myofibrils l Each myofibril is made up of overlapping strands of actin and myosin l During a muscle twitch, the myosin filaments move relative to the actin filaments, thereby shortening the muscle fiber 8.3 Copyright 2001 by Allyn & Bacon Neuromuscular Junction n The neuromuscular junction is the synapse formed between an alpha motor neuron
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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.
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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.
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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.
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Profiling of the Muscle-Specific Dystroglycan Interactome Reveals the Role of Hippo Signaling in Muscular Dystrophy and Age-Dependent Muscle Atrophy Andriy S
Yatsenko et al. BMC Medicine (2020) 18:8 https://doi.org/10.1186/s12916-019-1478-3 RESEARCH ARTICLE Open Access Profiling of the muscle-specific dystroglycan interactome reveals the role of Hippo signaling in muscular dystrophy and age-dependent muscle atrophy Andriy S. Yatsenko1†, Mariya M. Kucherenko2,3,4†, Yuanbin Xie2,5†, Dina Aweida6, Henning Urlaub7,8, Renate J. Scheibe1, Shenhav Cohen6 and Halyna R. Shcherbata1,2* Abstract Background: Dystroglycanopathies are a group of inherited disorders characterized by vast clinical and genetic heterogeneity and caused by abnormal functioning of the ECM receptor dystroglycan (Dg). Remarkably, among many cases of diagnosed dystroglycanopathies, only a small fraction can be linked directly to mutations in Dg or its regulatory enzymes, implying the involvement of other, not-yet-characterized, Dg-regulating factors. To advance disease diagnostics and develop new treatment strategies, new approaches to find dystroglycanopathy-related factors should be considered. The Dg complex is highly evolutionarily conserved; therefore, model genetic organisms provide excellent systems to address this challenge. In particular, Drosophila is amenable to experiments not feasible in any other system, allowing original insights about the functional interactors of the Dg complex. Methods: To identify new players contributing to dystroglycanopathies, we used Drosophila as a genetic muscular dystrophy model. Using mass spectrometry, we searched for muscle-specific Dg interactors. Next, in silico analyses allowed us to determine their association with diseases and pathological conditions in humans. Using immunohistochemical, biochemical, and genetic interaction approaches followed by the detailed analysis of the muscle tissue architecture, we verified Dg interaction with some of the discovered factors.
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CAP2 Deficiency Delays Myofibril Actin Cytoskeleton Differentiation and Disturbs Skeletal Muscle Architecture and Function
CAP2 deficiency delays myofibril actin cytoskeleton differentiation and disturbs skeletal muscle architecture and function Lara-Jane Kepsera, Fidan Damara, Teresa De Ciccob, Christine Chaponnierc, Tomasz J. Prószynski b, Axel Pagenstecherd, and Marco B. Rusta,e,f,1 aMolecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032 Marburg, Germany; bLaboratory of Synaptogenesis, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland; cDepartment of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland; dInstitute of Neuropathology, University of Marburg, 35032 Marburg, Germany; eCenter for Mind, Brain and Behavior, Research Campus of Central Hessen, 35032 Marburg, Germany; and fDFG Research Training Group “Membrane Plasticity in Tissue Development and Remodeling,” GRK 2213, University of Marburg, 35032 Marburg, Germany Edited by Yale E. Goldman, University of Pennsylvania/PMI, Philadelphia, PA, and approved March 14, 2019 (received for review August 7, 2018) Actin filaments (F-actin) are key components of sarcomeres, the have acquired specific functions. While previous analyses of mu- basic contractile units of skeletal muscle myofibrils. A crucial step tant mice demonstrated a role of CAP2 in neuron morphology and during myofibril differentiation is the sequential exchange of heart physiology (13–15), its function in skeletal muscles has not α-actin isoforms from smooth muscle (α-SMA) and cardiac (α-CAA) been investigated, yet. to skeletal muscle α-actin (α-SKA) that, in mice, occurs during early We here report a function for CAP2 in skeletal muscle de- postnatal life. This “α-actin switch” requires the coordinated activ- velopment. We found that CAP2 controls the exchange of ity of actin regulators because it is vital that sarcomere structure α-actin isoforms during myofibril differentiation.
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CANDIDATE GENES in the FIELD of EXERCISE GENOMICS Abstract
EXERCISE AND QUALITY OF LIFE Review article Volume 3, No. 1, 2011, 23-29 575.113:612.74 UDC CANDIDATE GENES IN THE FIELD OF EXERCISE GENOMICS ã Vladimir Gali Department of Physiology Medical faculty Novi Sad Abstract Skeletal muscle is extremely adaptable to various stresses which can be placed upon it. In spite of importance of skeletal muscles, little is known about genetic factors which demonstrate high influence to muscle size, function, strength and adaptation to various environmental factors. Because endurance performance is a multifactorial trait, the list of candidate genes which could account for human variation in related phenotypes is extensive. One of the first characterized and most frequently studied genetic variant is a polymorphism in the angiotensin converting enzyme I gene. The ACTN3 gene is the first structural skeletal muscle gene with a relation between its ’ performance. N genotype and elite sprinter evertheless, current genetic testing cannot provide an extra advantage over existing testing methods in determining sports selection in young athletes. The main challenge still remains to identify other, complex polygenetic variants and their interactions with environmental factors which could provide benefit in the sports selection and existing talent identification. Keywords: exercise genomics, genetic polymorphism, muscle tissue Introduction Muscle tissue constitutes approximately 30% of body mass, it is metabolically very active with high turnover of energy and is capable of efficient response to different environmental stimuli. Skeletal muscle is extremely adaptable to various stresses which can be placed upon it. These adaptations can be either positive, such as tissue growth, extreme athletic performance or reparation of an injury, or negative, such as decline in mass and function over the ’s years of disuse or disease.
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