DOCSLIB.ORG

Skeletal Muscle Tissue

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Skeletal Muscle Tissue 9 Skeletal Muscle Tissue Lecture Presentation by Lori Garrett © 2018 Pearson Education, Inc. Section 1: Functional Anatomy of Skeletal Muscle Tissue Learning Outcomes 9.1 Describe the functions of skeletal muscle tissue. 9.2 Describe the organization of skeletal muscle at the tissue level. 9.3 Describe the structures of a sarcomere. 9.4 Describe the structures of a thin filament and a thick filament. 9.5 Describe a major characteristic of excitable membranes and its importance in generating an action potential. © 2018 Pearson Education, Inc. Section 1: Functional Anatomy of Skeletal Muscle Tissue Learning Outcomes (continued) 9.6 Identify the components of the neuromuscular junction, and summarize the events involved in the control of skeletal muscles by motor neurons. 9.7 Describe the role of ATP in a muscle contraction, and explain the steps involved in the contraction of a skeletal muscle fiber. © 2018 Pearson Education, Inc. Module 9.1: Skeletal muscle tissue enables body movement and other vital functions Muscle tissue—mostly muscle cells specialized for contraction. 3 types: skeletal muscle, cardiac muscle, smooth muscle Skeletal muscle cell = muscle fiber Skeletal muscle . = an organ made of mostly skeletal muscle tissue, plus connective tissue, nerves, blood vessels . Directly/indirectly attached to bones (hence skeletal muscle) © 2018 Pearson Education, Inc. Module 9.1: Skeletal muscle tissue functions Functions of skeletal muscle tissue 1. Produce body movement Muscle tendons pull and move bones 2. Maintain posture and body Stabilize joints position 3. Support soft tissues Surround, support, and shield internal structures, such as tissues and organs 4..Guard[Insert body fig_09_01A -L.jpgSphincters here] encircle openings; provide entrances/exits voluntary control of swallowing, defecation, and urination 5. Maintain body temperature Contraction uses energy; energy use generates heat 6. Store nutrients Muscle proteins can break down; release amino acids—can be used to synthesize glucose or provide energy © 2018 Pearson Education, Inc. Module 9.1: Skeletal muscle tissue functions Comparison of muscle tissue types Skeletal muscle tissue . Voluntary control . Produce movement by pulling on bones Cardiac muscle tissue . Involuntary . Only in heart . Pumps blood; circulating it in vessels © 2018 Pearson Education, Inc. Module 9.1: Skeletal muscle tissue functions Comparison of muscle tissue types (continued) Smooth muscle tissue . Involuntary . Walls of hollow organs, small arteries © 2018 Pearson Education, Inc. Module 9.1: Review A. Name the three types of muscle tissue, identify where they are found, and list their functions. B. Which muscle types are voluntary, and which are involuntary? Learning Outcome: Describe the functions of skeletal muscle tissue. © 2018 Pearson Education, Inc. Module 9.2: Skeletal muscle contains muscle tissue, connective tissues, blood vessels, and nerves Structure of a skeletal muscle Skeletal muscle = organ Epimysium = dense sheath of collagen fibers around muscle . Separates muscle from other tissues/organs . Connected to deep fascia (dense connective tissue layer—module 4.15) © 2018 Pearson Education, Inc. Module 9.2: Skeletal muscle structure Muscle fascicle = bundle of muscle fibers Perimysium = fibrous layer dividing muscle into compartments . Separates muscle fascicles . Has collagen and elastic fibers; blood vessels and nerves supplying muscle fibers within the fascicle © 2018 Pearson Education, Inc. Module 9.2: Skeletal muscle structure Skeletal muscle fibers = individual muscle cells . Contain myofibrils = bundles of protein filaments Endomysium = thin layer of areolar connective tissue around each muscle fiber; has collagen and elastic fibers, blood vessels/nerves supplying muscle fibers Myosatellite cells = stem cells that help repair damaged muscle tissue © 2018 Pearson Education, Inc. Module 9.2: Skeletal muscle structure Ends of skeletal muscles: connective tissue layers (epimysium, perimysium, endomysium) merge to form a tendon or aponeurosis . Tendon—attaches muscle to specific point on a bone . Aponeurosis—broad sheet with broad attachment to bone(s) . Contracting muscle pulls on tendon or aponeurosis, which pulls on and moves the bone © 2018 Pearson Education, Inc. Skeletal muscle structure © 2018 Pearson Education, Inc. Module 9.2: Skeletal muscle structure Skeletal muscle development Myoblasts = embryonic cells that fuse to form multinucleate cells that differentiate into skeletal muscle fibers. Some myoblasts remain free in endomysium as myosatellite cells that help repair damaged muscle tissue © 2018 Pearson Education, Inc. Module 9.2: Skeletal muscle structure The multinucleate cells differentiate into skeletal muscle fibers (cells) and start producing proteins for contraction Mature muscle cells are quite large compared to other cells . Diameters up to 100 µm . Length up to 30 cm (12 in.) © 2018 Pearson Education, Inc. Module 9.2: Skeletal muscle structure Multiple nuclei = more copies of genes for protein/enzyme production Special terms for skeletal muscle fibers: . Sarcolemma = plasma membrane . Sarcoplasm = cytoplasm © 2018 Pearson Education, Inc. Skeletal muscle development © 2018 Pearson Education, Inc. Module 9.2: Review A. Define tendon and aponeurosis. B. Describe the connective tissue layers associated with skeletal muscle tissue. C. What special terms are used to describe the plasma membrane and cytoplasm of a skeletal muscle fiber? D. How would severing a tendon attached to a muscle affect movement of that limb? Learning Outcome: Describe the organization of skeletal muscle at the tissue level. © 2018 Pearson Education, Inc. Module 9.3: Skeletal muscle fibers contain T tubules and sarco-plasmic reticula that surround contractile myofibrils made up of sarcomeres Myofibrils Myofibril = small cylindrical structures arranged parallel inside muscle fiber; run length of muscle fiber . Myofibril arrangement gives skeletal muscle appearance of having stripes (striations) . Many mitochondria along myofibrils © 2018 Pearson Education, Inc. Module 9.3: Skeletal muscle fiber contents Myofilaments Myofilaments = bundles of protein filaments inside myofibrils . Thin filaments mostly composed of actin . Thick filaments mostly composed of myosin © 2018 Pearson Education, Inc. Module 9.3: Skeletal muscle fiber contents Sarcomeres and striations Sarcomeres = repeating functional units of skeletal muscle fiber . ~10,000 sarcomeres/myofibril, each ~2 µm resting length . Striations: • Z lines • I band • A band • M line • H band © 2018 Pearson Education, Inc. Module 9.3: Skeletal muscle fiber contents Z lines—Junction of adjacent sarcomeres; proteins (actinins) connect thin filaments of adjacent sarcomeres here I band—Lighter band with only thin filaments A band—Dark/dense region containing thick filaments Zone of overlap—Within A band; overlapping thick/thin filaments M line—Center of A band where adjacent thick filaments connect H band—Lighter region on each side of M line with only thick filaments; visible only in resting sarcomeres © 2018 Pearson Education, Inc. Module 9.3: Skeletal muscle fiber contents Sarcolemma Sarcolemma = plasma membrane of a skeletal muscle fiber . Selective permeability allows uneven distribution of +/– charges Reversal of charge is 1st step leading to muscle contraction . Change in charge initiated by nerve cell (neuron) impulse and spreads across entire sarcolemma © 2018 Pearson Education, Inc. Module 9.3: Skeletal muscle fiber contents Transverse tubules (T tubules) . Continuous with sarcolemma and extend into sarcoplasm . Form passageways through muscle fiber and encircle sarcomere © 2018 Pearson Education, Inc. Module 9.3: Skeletal muscle fiber contents Sarcoplasmic reticulum . Similar to smooth endoplasmic reticulum of other cells . Enlarged sections (terminal cisternae) on either side of T tubule . Triad = pair of terminal cisternae and one T tubule © 2018 Pearson Education, Inc. Module 9.3: Skeletal muscle fiber contents Sarcoplasmic reticulum (continued) . Sarcoplasmic reticulum (SR) stores calcium ions that are actively pumped in from cytosol • Calsequestrin = protein that binds calcium inside SR . Muscle contraction starts when stored calcium ions are released from SR into cytosol (via gated calcium channels) © 2018 Pearson Education, Inc. Module 9.3: Review A. Describe the structures of a sarcomere. B. Define transverse tubules. C. Within a resting skeletal muscle fiber, where is the greatest concentration of Ca2+? Learning Outcome: Describe the structures of a sarcomere. © 2018 Pearson Education, Inc. Module 9.4: The sliding of thin filaments past thick filaments produces muscle contraction Structure of thin filaments . Attached to Z lines with actinin . Composed of 4 main proteins: 1. F-actin 2. Nebulin 3. Tropomyosin 4. Troponin © 2018 Pearson Education, Inc. Module 9.4: Sliding filaments Structure of thin filaments (continued) 1. F-actin (filamentous)—twisted double-strand of G-actin • G-actin molecules each have active site for binding myosin 2. Nebulin—holds two strands of G-actin molecules together © 2018 Pearson Education, Inc. Module 9.4: Sliding filaments Structure of thin filaments (continued) 3. Tropomyosin—double-stranded protein wrapped around F-actin • Blocks myosin binding sites on G-actin molecules • Prevents actin/myosin interaction 4. Troponin—made of 3 subunits • Attached to tropomyosin; = troponin-tropomyosin complex • Also attached to G-actin and has binding sites for Ca2+ © 2018 Pearson Education, Inc. Module
Load more

Recommended publications
  • 1933.Full.Pdf
    0270.6474/84/0408-1933$02.00/O The Journal of Neuroscience Copyright 0 Society for Neuroscience Vol. 4, No. 8, pp. 1933-1943 Printed in U.S.A. August 1984 PARTIAL PURIFICATION AND FUNCTIONAL IDENTIFICATION OF A CALMODULIN-ACTIVATED, ADENOSINE 5’-TRIPHOSPHATE-DEPENDENT CALCIUM PUMP FROM SYNAPTIC PLASMA MEMBRANES1 DIANE M. PAPAZIAN,* HANNAH RAHAMIMOFF,$ AND STANLEY M. GOLDIN§’ Departments of *Biological Chemistry and $Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and *Department of Biochemistry, Hadassah Medical School, Hebrew University, Jerusalem, Israel Received July 18, 1983; Revised February 27, 1984; Accepted February 28, 1984 Abstract Synaptic plasma membranes isolated from rat brain contain a calmodulin-activated Ca2+ pump. It has been purified 80- to 160-fold by solubilization with Triton X-100 and affinity chromatography on a calmodulin- Sepharose 4B column. After reconstitution into phospholipid vesicles, the affinity-purified pump efficiently catalyzed ATP dependent Ca2+ transport, which was activated 7- to g-fold by calmodulin. The major protein component of the affinity-purified preparation had a M, = 140,000; it was virtually the only band visualized on a Coomassie blue-stained SDS polyacrylamide gel. It has been identified as the Ca”’ pump by two functional criteria. First, it was phosphorylated by [y-““P]ATP in a Ca’+-dependent manner; the phosphorylated protein had the chemical reactivity of an acyl phosphate, characteristic of the phosphorylated intermediates of ion-transporting ATPases. Second, the protein was enriched by transport-specific fractiona- tion, a density gradient procedure which uses the transport properties of the reconstituted Ca2+ pump as a physical tool for its purification.
    [Show full text]
  • 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.
    [Show full text]
  • VIEW Open Access Muscle Spindle Function in Healthy and Diseased Muscle Stephan Kröger* and Bridgette Watkins
    Kröger and Watkins Skeletal Muscle (2021) 11:3 https://doi.org/10.1186/s13395-020-00258-x REVIEW Open Access Muscle spindle function in healthy and diseased muscle Stephan Kröger* and Bridgette Watkins Abstract Almost every muscle contains muscle spindles. These delicate sensory receptors inform the central nervous system (CNS) about changes in the length of individual muscles and the speed of stretching. With this information, the CNS computes the position and movement of our extremities in space, which is a requirement for motor control, for maintaining posture and for a stable gait. Many neuromuscular diseases affect muscle spindle function contributing, among others, to an unstable gait, frequent falls and ataxic behavior in the affected patients. Nevertheless, muscle spindles are usually ignored during examination and analysis of muscle function and when designing therapeutic strategies for neuromuscular diseases. This review summarizes the development and function of muscle spindles and the changes observed under pathological conditions, in particular in the various forms of muscular dystrophies. Keywords: Mechanotransduction, Sensory physiology, Proprioception, Neuromuscular diseases, Intrafusal fibers, Muscular dystrophy In its original sense, the term proprioception refers to development of head control and walking, an early im- sensory information arising in our own musculoskeletal pairment of fine motor skills, sensory ataxia with un- system itself [1–4]. Proprioceptive information informs steady gait, increased stride-to-stride variability in force us about the contractile state and movement of muscles, and step length, an inability to maintain balance with about muscle force, heaviness, stiffness, viscosity and ef- eyes closed (Romberg’s sign), a severely reduced ability fort and, thus, is required for any coordinated move- to identify the direction of joint movements, and an ab- ment, normal gait and for the maintenance of a stable sence of tendon reflexes [6–12].
    [Show full text]
  • Muscle Tissue
    10 Muscle Tissue PowerPoint® Lecture Presentations prepared by Jason LaPres Lone Star College—North Harris © 2012 Pearson Education, Inc. 10-1 An Introduction to Muscle Tissue • Learning Outcomes • 10-1 Specify the functions of skeletal muscle tissue. • 10-2 Describe the organization of muscle at the tissue level. • 10-3 Explain the characteristics of skeletal muscle fibers, and identify the structural components of a sarcomere. • 10-4 Identify the components of the neuromuscular junction, and summarize the events involved in the neural control of skeletal muscle contraction and relaxation. © 2012 Pearson Education, Inc. 10-1 An Introduction to Muscle Tissue • Learning Outcomes • 10-5 Describe the mechanism responsible for tension production in a muscle fiber, and compare the different types of muscle contraction. • 10-6 Describe the mechanisms by which muscle fibers obtain the energy to power contractions. • 10-7 Relate the types of muscle fibers to muscle performance, and distinguish between aerobic and anaerobic endurance. © 2012 Pearson Education, Inc. 10-1 An Introduction to Muscle Tissue • Learning Outcomes • 10-8 Identify the structural and functional differences between skeletal muscle fibers and cardiac muscle cells. • 10-9 Identify the structural and functional differences between skeletal muscle fibers and smooth muscle cells, and discuss the roles of smooth muscle tissue in systems throughout the body. © 2012 Pearson Education, Inc. An Introduction to Muscle Tissue • Muscle Tissue • A primary tissue type, divided into: • Skeletal muscle tissue • Cardiac muscle tissue • Smooth muscle tissue © 2012 Pearson Education, Inc. 10-1 Functions of Skeletal Muscle Tissue • Skeletal Muscles • Are attached to the skeletal system • Allow us to move • The muscular system • Includes only skeletal muscles © 2012 Pearson Education, Inc.
    [Show full text]
  • 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.
    [Show full text]
  • Desmin- Cytoskeleton Marker Cat#: ET1606-30
    rev. 04/13/16 Desmin- Cytoskeleton Marker Cat#: ET1606-30 Prod uct Type: R ecombinant r abbit mono clonal IgG, primary antibodies Species reactivity: Human, Mouse, Rat, Zebra fish Applications： WB, ICC/IF, IHC, FC Molecular Wt.： 53 kDa Description： Cytoskeletal intermediate filaments (IFs) constitute a diverse group of proteins that are expressed in a highly tissue - specific manner. IFs are constructed from two - chain α -helical coiled-coil molecules arranged on an imperfect helical Fig1: Western blot analysis of Desmin on lattice, and have been widely used as markers for distinguishing different lysates using anti-Desmin antibody at individual cell types within a tissue and identifying the origins 1/1,000 dilution. of metastatic tumors. Vimentin is an IF general marker of cells Positive control: originating in the mesenchyme. Vimentin and Desmin, a related class III IF, are both expressed during skeletal muscle development. Lane 1: Human skeletal muscle Desmin, a 469 amino acid protein found near the Z line in sarcomeres, Lane 2: Mouse heart is expressed more frequently in adult differentiated state tissues. Desmin makes up attachments between the terminal Z-disc and membrane-associated proteins to form a force-transmitting system. Mutations in the gene encoding for Desmin are associated with adult-onset skeletal myopathy, sporadic disease and mild cardiac involvement. Immunogen： Recombinant protein. Positive control： Fig2: ICC staining Desmin in C2C12 cells (green). C2C12, human uterus tissue, mouse bladder tissue, mouse heart The nuclear counter stain is DAPI (blue). Cells tissue, mouse skeletal muscle tissue. were fixed in paraformaldehyde, permeabilised with 0.25% Triton X100/PBS.
    [Show full text]
  • Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria
    Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) Servizo de Normalización Lingüística Universidade de Santiago de Compostela COLECCIÓN VOCABULARIOS TEMÁTICOS N.º 4 SERVIZO DE NORMALIZACIÓN LINGÜÍSTICA Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) 2008 UNIVERSIDADE DE SANTIAGO DE COMPOSTELA VOCABULARIO de morfoloxía, anatomía e citoloxía veterinaria : (galego-español- inglés) / coordinador Xusto A. Rodríguez Río, Servizo de Normalización Lingüística ; autores Matilde Lombardero Fernández ... [et al.]. – Santiago de Compostela : Universidade de Santiago de Compostela, Servizo de Publicacións e Intercambio Científico, 2008. – 369 p. ; 21 cm. – (Vocabularios temáticos ; 4). - D.L. C 2458-2008. – ISBN 978-84-9887-018-3 1.Medicina �������������������������������������������������������������������������veterinaria-Diccionarios�������������������������������������������������. 2.Galego (Lingua)-Glosarios, vocabularios, etc. políglotas. I.Lombardero Fernández, Matilde. II.Rodríguez Rio, Xusto A. coord. III. Universidade de Santiago de Compostela. Servizo de Normalización Lingüística, coord. IV.Universidade de Santiago de Compostela. Servizo de Publicacións e Intercambio Científico, ed. V.Serie. 591.4(038)=699=60=20 Coordinador Xusto A. Rodríguez Río (Área de Terminoloxía. Servizo de Normalización Lingüística. Universidade de Santiago de Compostela) Autoras/res Matilde Lombardero Fernández (doutora en Veterinaria e profesora do Departamento de Anatomía e Produción Animal.
    [Show full text]
  • The Muscular System
    THE MUSCULAR SYSTEM COMPILED BY HOWIE BAUM 1 Muscles make up the bulk of the body and account for 1/3 of its weight.!! Blood vessels and nerves run to every muscle, helping control and regulate each muscle’s function. The muscular system creates body heat and also moves the: Bones of the Skeletal system Food through Digestive system Blood through the Circulatory system Fluids through the Excretory system MUSCLE TISSUE The body has 3 main types of muscle tissue 1) Skeletal, 2) Smooth, and 3) Cardiac SKELETAL MUSCLE SMOOTH MUSCLE CARDIAC MUSCLE Skeletal muscles attach to and move bones by contracting and relaxing in response to voluntary messages from the nervous system. Skeletal muscle tissue is composed of long cells called muscle fibers that have a striated appearance. Muscle fibers are organized into bundles supplied by blood vessels and innervated by motor neurons. Muscle structure Skeletal (striated or voluntary) muscle consists of densely packed groups of hugely elongated cells known as myofibers. These are grouped into bundles (fascicles). A typical myofiber is 2–3 centimeters ( 3/4–1 1/5 in) long and 0.05millimeters (1/500 inch) in diameter and is composed of narrower structures – myofibrils. These contain thick and thin myofilaments made up mainly of the proteins actin and myosin. Numerous capillaries keep the muscle supplied with the oxygen and glucose needed to fuel contraction. Skeletal Muscles • Skeletal muscles attach to bones by tendons (connective tissue) and enable movement. • Skeletal muscles are mostly voluntary Feel the back of your ankle to feel your Achilles tendon - the largest tendon in your body.
    [Show full text]
  • Passive Tension in Cardiac Muscle: Contribution of Collagen, Titin, Microtubules, and Intermediate Filaments
    Biophysical Journal Volume 68 March 1995 1027-1044 1027 Passive Tension in Cardiac Muscle: Contribution of Collagen, Titin, Microtubules, and Intermediate Filaments Henk L. Granzier and Thomas C. Irving Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University, Pullman, Washington 99164·6520 USA ABSTRACT The passive tension-sarcomere length relation of rat cardiac muscle was investigated by studying passive (or not activated) single myocytes and trabeculae. The contribution ofcollagen, titin, microtubules, and intermediate filaments to tension and stiffness was investigated by measuring (1) the effects of KCI/KI extraction on both trabeculae and single myocytes, (2) the effect of trypsin digestion on single myocytes, and (3) the effect of colchicine on single myocytes. It was found that over the working range of sarcomeres in the heart (lengths -1.9-2.2 11m), collagen and titin are the most important contributors to passive tension with titin dominating at the shorter end of the working range and collagen at longer lengths. Microtubules made a modest contribution to passive tension in some cells, but on average their contribution was not significant. Finally, intermediate filaments contribl,!ted about 10%to passive tension oftrabeculae at sarcomere lengths from -1.9to 2.1 11m, and theircontribution dropped to only a few percent at longer lengths. At physiological sarcomere lengths of the heart, cardiac titin developed much higher tensions (>20-fold) than did skeletal muscle titin at comparable lengths. This might be related to the finding that cardiac titin has a molecular mass of 2.5 MDa, 0.3-0.5 MDa smaller than titin of mammalian skeletal muscle, which is predicted to result in a much shorter extensible titin segment in the I-band of cardiac muscle.
    [Show full text]
  • Muscle Histology
    Muscle Histology Dr. Heba Kalbouneh Functions of muscle tissue ▪ Movement ▪ Maintenance of posture ▪ Joint stabilization ▪ Heat generation Types of Muscle Tissue ▪ Skeletal muscle ▪ Cardiac muscle ▪ Smooth muscle Types of Muscle Tissue Skeletal •Attach to and move skeleton •40% of body weight •Fibers = multinucleate cells (embryonic cells fuse) •Cells with obvious striations •Contractions are voluntary Cardiac: only in the wall of the heart •Cells are striated •Contractions are involuntary (not voluntary) Smooth: walls of hollow organs •Lack striations •Contractions are involuntary (not voluntary) Similarities… ▪ Their cells are called fibers because they are elongated ▪ Contraction depends on myofilaments ▪ Actin ▪ Myosin ▪ Plasma membrane is called sarcolemma ▪ Sarcos = flesh ▪ Lemma = sheath SKELETAL MUSCLES Epimysium: surrounds whole muscle Endomysium is around each muscle fiber Perimysium is around fascicle = muscle cell= myofiber Skeletal muscle This big cylinder is a fiber: a cell ▪ Fibers (each is one cell) have striations ▪ Myofibrils are organelles of the cell: these are made -an organelle up of myofilaments ▪ Sarcomere ▪ Basic unit of contraction ▪ Myofibrils are long rows of repeating sarcomeres ▪ Boundaries: Z discs (or lines) Sarcomere M line provides an attachment to myosin filaments Z line provides an attachment to actin filaments A band is the darker band of the myofibril containing myosin filaments H band is the lighter section in the middle of the A band where only myosin is present I band is the lighter band containing
    [Show full text]
  • 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.
    [Show full text]
  • GLOSSARY of MEDICAL and ANATOMICAL TERMS
    GLOSSARY of MEDICAL and ANATOMICAL TERMS Abbreviations: • A. Arabic • abb. = abbreviation • c. circa = about • F. French • adj. adjective • G. Greek • Ge. German • cf. compare • L. Latin • dim. = diminutive • OF. Old French • ( ) plural form in brackets A-band abb. of anisotropic band G. anisos = unequal + tropos = turning; meaning having not equal properties in every direction; transverse bands in living skeletal muscle which rotate the plane of polarised light, cf. I-band. Abbé, Ernst. 1840-1905. German physicist; mathematical analysis of optics as a basis for constructing better microscopes; devised oil immersion lens; Abbé condenser. absorption L. absorbere = to suck up. acervulus L. = sand, gritty; brain sand (cf. psammoma body). acetylcholine an ester of choline found in many tissue, synapses & neuromuscular junctions, where it is a neural transmitter. acetylcholinesterase enzyme at motor end-plate responsible for rapid destruction of acetylcholine, a neurotransmitter. acidophilic adj. L. acidus = sour + G. philein = to love; affinity for an acidic dye, such as eosin staining cytoplasmic proteins. acinus (-i) L. = a juicy berry, a grape; applied to small, rounded terminal secretory units of compound exocrine glands that have a small lumen (adj. acinar). acrosome G. akron = extremity + soma = body; head of spermatozoon. actin polymer protein filament found in the intracellular cytoskeleton, particularly in the thin (I-) bands of striated muscle. adenohypophysis G. ade = an acorn + hypophyses = an undergrowth; anterior lobe of hypophysis (cf. pituitary). adenoid G. " + -oeides = in form of; in the form of a gland, glandular; the pharyngeal tonsil. adipocyte L. adeps = fat (of an animal) + G. kytos = a container; cells responsible for storage and metabolism of lipids, found in white fat and brown fat.
    [Show full text]