Chapter 7 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. -
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. -
Single-Cell Analysis Uncovers Fibroblast Heterogeneity
ARTICLE https://doi.org/10.1038/s41467-020-17740-1 OPEN Single-cell analysis uncovers fibroblast heterogeneity and criteria for fibroblast and mural cell identification and discrimination ✉ Lars Muhl 1,2 , Guillem Genové 1,2, Stefanos Leptidis 1,2, Jianping Liu 1,2, Liqun He3,4, Giuseppe Mocci1,2, Ying Sun4, Sonja Gustafsson1,2, Byambajav Buyandelger1,2, Indira V. Chivukula1,2, Åsa Segerstolpe1,2,5, Elisabeth Raschperger1,2, Emil M. Hansson1,2, Johan L. M. Björkegren 1,2,6, Xiao-Rong Peng7, ✉ Michael Vanlandewijck1,2,4, Urban Lendahl1,8 & Christer Betsholtz 1,2,4 1234567890():,; Many important cell types in adult vertebrates have a mesenchymal origin, including fibro- blasts and vascular mural cells. Although their biological importance is undisputed, the level of mesenchymal cell heterogeneity within and between organs, while appreciated, has not been analyzed in detail. Here, we compare single-cell transcriptional profiles of fibroblasts and vascular mural cells across four murine muscular organs: heart, skeletal muscle, intestine and bladder. We reveal gene expression signatures that demarcate fibroblasts from mural cells and provide molecular signatures for cell subtype identification. We observe striking inter- and intra-organ heterogeneity amongst the fibroblasts, primarily reflecting differences in the expression of extracellular matrix components. Fibroblast subtypes localize to discrete anatomical positions offering novel predictions about physiological function(s) and regulatory signaling circuits. Our data shed new light on the diversity of poorly defined classes of cells and provide a foundation for improved understanding of their roles in physiological and pathological processes. 1 Karolinska Institutet/AstraZeneca Integrated Cardio Metabolic Centre, Blickagången 6, SE-14157 Huddinge, Sweden. -
Nomina Histologica Veterinaria, First Edition
NOMINA HISTOLOGICA VETERINARIA Submitted by the International Committee on Veterinary Histological Nomenclature (ICVHN) to the World Association of Veterinary Anatomists Published on the website of the World Association of Veterinary Anatomists www.wava-amav.org 2017 CONTENTS Introduction i Principles of term construction in N.H.V. iii Cytologia – Cytology 1 Textus epithelialis – Epithelial tissue 10 Textus connectivus – Connective tissue 13 Sanguis et Lympha – Blood and Lymph 17 Textus muscularis – Muscle tissue 19 Textus nervosus – Nerve tissue 20 Splanchnologia – Viscera 23 Systema digestorium – Digestive system 24 Systema respiratorium – Respiratory system 32 Systema urinarium – Urinary system 35 Organa genitalia masculina – Male genital system 38 Organa genitalia feminina – Female genital system 42 Systema endocrinum – Endocrine system 45 Systema cardiovasculare et lymphaticum [Angiologia] – Cardiovascular and lymphatic system 47 Systema nervosum – Nervous system 52 Receptores sensorii et Organa sensuum – Sensory receptors and Sense organs 58 Integumentum – Integument 64 INTRODUCTION The preparations leading to the publication of the present first edition of the Nomina Histologica Veterinaria has a long history spanning more than 50 years. Under the auspices of the World Association of Veterinary Anatomists (W.A.V.A.), the International Committee on Veterinary Anatomical Nomenclature (I.C.V.A.N.) appointed in Giessen, 1965, a Subcommittee on Histology and Embryology which started a working relation with the Subcommittee on Histology of the former International Anatomical Nomenclature Committee. In Mexico City, 1971, this Subcommittee presented a document entitled Nomina Histologica Veterinaria: A Working Draft as a basis for the continued work of the newly-appointed Subcommittee on Histological Nomenclature. This resulted in the editing of the Nomina Histologica Veterinaria: A Working Draft II (Toulouse, 1974), followed by preparations for publication of a Nomina Histologica Veterinaria. -
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. -
MODULE 1: HISTOLOGY I an Introduction to Histology; Begin Epithelial Tissue and Connective Tissue
MODULE 1: HISTOLOGY I An Introduction to Histology; Begin Epithelial Tissue and Connective Tissue Histology is the study of the microscopic anatomy of the cells and extracellular matrix that make up the tissues of the body. Using the physical appearance of cells and the matrix that surrounds them, the 10-100 trillion cells of the human body can be grouped into just four major tissue types: epithelial, connective, muscle and nervous tissues. In the Histology Modules of this course, you will learn to identify each of these tissue types as well as their subclasses and important structures. Chemical fixatives are used to preserve tissues when they are harvested. These fixatives are important to preserve the tissue from degradation. These chemicals also destroy the biological function of the cells, so all of the cells in any micrograph images that you see are dead. Biological tissue has little inherent color. In fact, in reality, the tissues that you study would look transparent or have various shades of gray for the most part. However, scientists use staining techniques to help highlight particular features of a tissue. As a student of histology, you should avoid the temptation to memorize tissues based on color. Since it is possible to stain the same tissue with a variety of different colors, you could be easily fooled if you trained yourself to recognize color as the major feature of tissues that you study. The wiser approach would be to carefully learn the shapes and physical characteristics other than color when studying histology. Students who memorize color as the main characteristic to trigger their memory will be disappointed when the exam does not maintain color schemes. -
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.