Place the Following Steps in Order of How a Muscle Contracts A) Neuron
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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. -
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. -
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]. -
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. -
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. -
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. -
Appropriate Roles of Cardiac Troponins in Evaluating Patients with Chest Pain
J Am Board Fam Pract: first published as 10.3122/jabfm.12.3.214 on 1 May 1999. Downloaded from MEDICAL PRACTICE Appropriate Roles of Cardiac Troponins in Evaluating Patients With Chest Pain Matthew S. Rice, MD, CPT, Me, USA, and David C. MacDonald, DO, Me, USA Background: Diagnosis of acute myocardial infarction relies upon the clinical history, interpretation of the electrocardiogram, and measurement of serum levels of cardiac enzymes. Newer biochemical markers of myocardial injury, such as cardiac troponin I and cardiac troponin T, are now being used instead of or along with the standard markers, the MB isoenzyme of creatine kinase (CK-MB) and lactate dehydrogenase. Methods: We performed a MEDLINE literature search (1987 to 1997) using the key words "troponin I," "troponin T," and "acute myocardial infarction." We reviewed selected articles related to the diagnostic and prognostic usefulness of these cardiac markers in evaluating patients with suspected myocardial infarction. Results: We found that (1) troponin I is a better cardiac marker than CK-MB for myocardial infarction because it is equally sensitive yet more specific for myocardial injury; (2) troponin T is a relatively poorer cardiac marker than CK-MB because it is less sensitive and less specific for myocardial injury; and (3) both troponin I and troponin T may be used as independent prognosticators of future cardiac events. Conclusions: Troponin I is a sensitive and specific marker for myocardial injury and can be used to predict the likelihood of future cardiac events. It is not much more expensive to measure than CK-MB. Over all, troponin I is a better cardiac marker than CK-MB and should become the preferred cardiac enzyme when evaluating patients with suspected myocardial infarction. -
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 -
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. -
Familial Adenomatous Polyposis Polymnia Galiatsatos, M.D., F.R.C.P.(C),1 and William D
American Journal of Gastroenterology ISSN 0002-9270 C 2006 by Am. Coll. of Gastroenterology doi: 10.1111/j.1572-0241.2006.00375.x Published by Blackwell Publishing CME Familial Adenomatous Polyposis Polymnia Galiatsatos, M.D., F.R.C.P.(C),1 and William D. Foulkes, M.B., Ph.D.2 1Division of Gastroenterology, Department of Medicine, The Sir Mortimer B. Davis Jewish General Hospital, McGill University, Montreal, Quebec, Canada, and 2Program in Cancer Genetics, Departments of Oncology and Human Genetics, McGill University, Montreal, Quebec, Canada Familial adenomatous polyposis (FAP) is an autosomal-dominant colorectal cancer syndrome, caused by a germline mutation in the adenomatous polyposis coli (APC) gene, on chromosome 5q21. It is characterized by hundreds of adenomatous colorectal polyps, with an almost inevitable progression to colorectal cancer at an average age of 35 to 40 yr. Associated features include upper gastrointestinal tract polyps, congenital hypertrophy of the retinal pigment epithelium, desmoid tumors, and other extracolonic malignancies. Gardner syndrome is more of a historical subdivision of FAP, characterized by osteomas, dental anomalies, epidermal cysts, and soft tissue tumors. Other specified variants include Turcot syndrome (associated with central nervous system malignancies) and hereditary desmoid disease. Several genotype–phenotype correlations have been observed. Attenuated FAP is a phenotypically distinct entity, presenting with fewer than 100 adenomas. Multiple colorectal adenomas can also be caused by mutations in the human MutY homologue (MYH) gene, in an autosomal recessive condition referred to as MYH associated polyposis (MAP). Endoscopic screening of FAP probands and relatives is advocated as early as the ages of 10–12 yr, with the objective of reducing the occurrence of colorectal cancer. -
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.