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PSE4U EXERCISE SCIENCE MUSCULAR SYSTEM CAROUSEL ACTIVITY Student Resource (Assignment) Instructions: In groups of 2, students use resources provided (e.g., software, video, internet sites, textbooks) to complete worksheets describing the features of neuromuscular principles and theories. Each group is assigned a topic to research and will present its findings to the class in a carousel format. Students will have some class time to research their topic. The organizational structure for the carousel is dependent on the number of students in the class (e.g., sixteen students equal eight stations equal eight pairs). Assuming an eight-station carousel format, student "A" becomes the expert and presents his or her findings to his/her peers for four rotations. Students record the information presented as they move from station to station. After four rotations, student "B" becomes the expert and presents his or her findings for the rest of the rotations (5-8). During rotations, peers check for correctness using an observation checklist. Teacher assesses each presenter using a communication rubric. At the completion of the carousel, students return to their pair to share information gathered on the features of neuromuscular principle and theories presented Some neuromuscular principles and theories that could be considered: The Sliding Filament Theory The Motor Unit The Neuromuscular Junction Muscular Structure The Role of Calcium / ATP The “All or Nothing” Principle (Law) The Proprioceptor System (e.g., golgi tendon organ, muscle spindles) The Reflex Arc There will be a library research period on Wednesday, 23 February, 2011.. A GRAPHIC ORGANIZER (attached) will be presented to the teacher during next class (Thursday, February 24); next class will be a computer lab period in Lab 106. Monday, February 28, 2011 will be an in-class work period in Period 2. Carousel activity will take place on Tuesday March 1, 2011. (St. David’s Day) PSE4U EXERCISE SCIENCE COMMUNICATION RUBRIC FOR MUSCLE CAROUSEL ACTIVITY The following assessment tool will be used to assess communication skills throughout the Exercise Science Course. Achievement Chart Category: Communication Communication Level One Level Two Criteria (50%-59%) (60%-69%) 1. Communication - communicates - communicates of information information with information with about function of limited clarity some clarity muscular system. -demonstrates -demonstrates limited some understanding of understanding of facts, concepts, facts, concepts, theories. theories. -provides few -provides some supportive details supportive details and answers to and answers to audience audience questions questions 2. Communication of information based on research suitable for an oral presentation to the carousel activity Look fors: Sending Verbal Messages (oral report) Presentation Skills - communicates with a limited sense of audience and purpose - PSE4U SCORING TOOL: - communicates with a some sense of audience and purpose Level Three (70%-79%) - communicates information with considerable clarity -demonstrates good understanding of facts, concepts, theories. -provides supportive details and answers to audience questions - communicates with a clear sense of audience and purpose Level Four (80%-100%) - communicates information with a high degree of clarity and with confidence -demonstrates extensive understanding of facts, concepts, theories. -provides many supportive details and answers to audience questions - communicates with a strong sense of audience and purpose clear articulate interesting diction effective voice volume/inflection eye contact with the audience appropriate facial expression, body language and gestures effective pacing projects energy and interest logical progression or linked thoughts presentation skills (e.g., controlled use of voice, body language, presentation style, effective use of media/technology) organization (e.g., effective opening/closing, appropriate development of parts of the presentation, thoughtful sequencing of ideas) creativity (e.g., audience involvement, effective use of props/visuals) provokes thoughtful audience responses GRAPHIC ORGANIZER Student’s Name: ________________________________ Topic: _________________________________________ Evaluator: Teacher: ___________ Peer: ______________ Type of Graphic Organizer: ______________ Word Web Flow Chart Timeline Suitable Title? Yes Criteria Knowledge/ Understanding Visual communication of information and ideas Written communication of information and ideas Overall Achievement Level: No Self: ____________ Other: _____/1 Mark Assigned Level 1 Level 2 Level 3 Level 4 Organizer demonstrated limited knowledge of facts and terms Organizer demonstrated some knowledge of facts and terms Organizer demonstrated considerable knowledge of facts and terms Organizer demonstrated thorough knowledge of facts and terms _____/3 Information and ideas communicated with limited clarity Information and ideas communicated with some clarity Information and ideas communicated with considerable clarity Information and ideas communicated with thorough clarity _____/3 Information and ideas communicated with limited clarity Information and ideas communicated with some clarity Information and ideas communicated with considerable clarity Information and ideas communicated with thorough clarity _____/3 Total Mark: _____/10 TEACHER NOTES: Neuromuscular principles and theories background information: Muscle Structure Skeletal muscle is an organ that contains muscle tissue, connective tissue, nerves and blood vessels Muscle cells, often called muscle fibres, are long, sometimes running the entire length of the muscle. They are the largest cells in our bodies. They are cylindrical cells about the diameter of a human hair and have many nuclei situated on the periphery of the cell which give them a striated appearance under low magnification The epimysium covers the body’s 430 (or more) skeletal muscles. The tendons attach to the bone on its connective tissue known as the periosteum Under the epimysium, the muscle fibres are grouped in bundled called fasciculi, that may consist of up to 150 fibres, which the bundles surrounded by connective tissue (epimysium) which encircles and is continuous with the fibre’s membrane the sarcolemma All of the tissues are continuous with the tendon, so tension that develops in one muscle cell can develop tension in the tendon Neuromuscular Junction The junction between a motor neuron (nerve cell) and the muscle fibres it innervates is called the motor end plate, or more often, the neuromuscular junction Each muscle cell has only one neuromuscular junction, although a single motor neuron innervates many muscle fibres, sometimes as many as several hundred A motor neuron and the muscle it innervates is called a motor unit; when stimulated all the muscle fibres of a motor unit contract together The sarcoplasm is the interior structure of the muscle fibre. The sarcoplasm contains contractile components which consists of protein filaments; other proteins; stored glycogen and fat particles; enzymes, and specialized structures such as mitochondria and the sarcoplasmic reticulum Hundreds of thousands of myofibrils each about the diameter of 1/100th the diameter of a human hair, dominate the sarcoplasm. Myofibrils contain the apparatus that contacts the muscle cell, which consists primarily of two types of myofilaments: myosin and actin. Myosin is referred to as thin filaments and the action is referred to as thick filaments. Globular heads called cross bridges protrude away from the myosin filament at regular intervals. The actin filaments consist of two strands arranged in a double helix. Two other proteins tropnin and tropomyolsin, are in-between the actin filament. Myosin and actin filaments are the smallest contractile unit of skeletal muscle known as the sarcomere. Sarcomeres run longitudinally along the entire muscle fibre Motor Unit The smallest independent unit controlled by the central nervous system is the motor unit Several motor units comprise the muscle body (the number depends on the individual muscle – small muscles in the eye may contain 6 to 7 motor units within the muscle body – larger skeletal muscles may have 200 motor units making up the muscle body) A motor unit is composed of a number of muscle fibres (the number depends on the individual muscle – small muscles in the eye may contain a few muscle fibres within the motor unit – large skeletal muscle may contain several hundred and its efferent motor nerve which innervates it When a motor unit is activated – all fibres within the motor unit are activated Sliding Filament Theory REST: At rest, the cross bridges extend toward action. The actin and myosin are now in a coupled position. The level of Calcium (Ca) concentration is low. STIMULATION: Myosin cross bridges form a type of bond with selected sites on the actin filaments. Actomyosin formation takes place. There is an immediate increase of intracellular Ca. This is brought about by the arrival of the action potential at the transverse tubules, which causes Ca to be released by the sarcoplasmic reticulum. The inhibitory action of troponin that prevents actin-myosin interaction is released when Ca ions bind rapidly with troponin in the actin filaments. Now the muscle is “turnedon”. CONTRACTION: Cross bridges swivel or collapse. The muscle shortens and the actin slides over the myosin. Tension develops. The ATP is broken down to ADP plus Pi plus energy. Contraction will continue as long as Ca ions remain at a level that inhibits the troponin-tropomyosin system RELAXATION: At the relaxation state, when the nerve stimulus to the muscle is removed, Ca ions move back into the sarcoplasmic reticulum (SR). The retrieval of Ca from the troponin-tropomyosin proteins “turns off” the active sites on the actin filaments. This deactivation accomplishes two things: 1) It prevents any mechanical link between the myosin cross-bridges and the actin filaments, 2) It reduces the activity of myosin ATPase so there is no more ATP splitting. Muscle now returns to resting state. Role of Calcium Following the depolarizing of the fibre’s membrane, the electrical impulse travels through the fibre’s network of tubules of the interior of the cell The arrival of an electrical charge causes the SR to release large qualities of stored calcium ions into the sarcoplasm In the resting state, tropomyosin is believed to lie on top of the active sites on the actin filaments, preventing binding of the myosin heads Once calcium ions are released from the sarcoplasmic reticulum, they bind with the troponin on the actin filaments Troponin, with its strong affinity from calcium ions, is believed to then initiate the actin process by lifting the tropomyosin molecules off of the active sites on the actin filaments Role of ATP Energizes the power stroke Disconnects actomyosin coupling Escorts calcium back into the sarcoplasmic reticulum The “All or None” Principle (Law) Muscular fibre or neuron responding completely when exposed to a threshold stimulus A skeletal muscular fibre exposed to a stimulus of threshold strength responds to its fullest extent Increasing the strength of the stimulus does not affect the fibre’s degree of contraction Therefore, a skeletal muscle fibre normally does not contract partially; if it contracts at all, it contracts completely, even though in some instances, it may not shorten completely The Proprioceptor System (e.g., Golgi Tendon Organ, Muscle Spindles) The term kinesthesia means conscious recognition of the position of the body parts with respect to on another as well as recognition of limb movement rates These functions are accomplished by extensive sensory devices in and around joints There are three principal types of proprioceptors: (1) free nerve endings, (2) Golgitype receptors, (3) pacinian corpuscles The most abundant of these are free nerve endings, which are sensitive to touch and pressure (these receptors are stimulated strongly at the beginning of movement; they adapt slightly at first, but then transmit a steady signal until the movement is complete. Golgi-type receptors are found in ligaments around joints and although they are not as abundant as free nerve endings, but they work in a similar manner Pacinian corpuscles are found in the tissues around joints and adapt rapidly following the initiation of movement Joint receptors work together to provide the body with a conscious means of recognition of the orientation of body parts as well as feedback about the rates of limb movement Reflex Arc A reflex arc is the nerve pathway from the receptor to the Central Nervous System and from the Central Nervous System along a motor pathway back to the effector organ Reflex contraction of skeletal muscles can occur in response to sensory input and not dependent on the activation of higher brain centres One purpose of a reflex is to provide a rapid means of removing a limb from a source of pain Note to Teachers Teachers need to create an observation checklist for the students’ presentations in the carousel activity. Criteria for the checklist could include: Knowledge/understanding - description of principle/theory, role/function of the principle/theory and its relevance to movement - appropriate supportive details - relevant and accurate information/ideas - answers questions and/or extends audience responses For more details, refer to the Communication Rubric in Teaching/learning Strategy #8 for this unit. Neuromuscular principles and theories background information adapted from the following resources: O.A.C. Physical and Health Education Core Concept A: Human Performance. The Halton District School Board Behnke, R. Kinetic Anatomy. Human Kinetics: Windsor, CA ISBN 0-7360-0016-X Kapit, W. and Elson, L. (2001). The Anatomy Colouring Book (3rd Edition). Benjamin Cummings: Toronto, CA 2001. ISBN 0-8053-5086-1 Powers, Scott K. Edward T. Howley. Exercise Physiology: Theory and Application to Fitness and Performance (4th Edition). New York, New York: McGraw-Hill Higher Educaton. 2001. ISBN: 0-07-235551-4 Robertson, T. & Glover, S. Senior Physical Education (Revised Edition). Coghill Publishing: Malvern, Australia ISBN 9491687-71-8 Shier, D., Bulter, J & Lweis, R. Hole's Essentials of Anatomy and Physiology. McGrawHill: Toronto, CA. 2000. ISBN 0-07-290775-4 Thompson, C. & Floyd, R. Manual of Structural Kinesiology (14th Edition). McGraw- Hill: Toronto, CA. 2001. ISBN 0-07-232917-3