KIN 3309 1nd Edition Lecture 3 Outline of Last Lecture I Hierarchy of Stuf II Types of Solid Materials III Stress and Strain IV Stress Strain Curve V Quiz VI Quiz VII Musculoskeletal System VIII Functions of the Skeleton IX Architecture of Bone X Types of Bone Tissue XI Types of Bone XII Bone Tissue XIII Ossification Modeling and Remodeling XIV Bone Tissue XV What would happen if the activity of bone cells was out of balance XVI Bones and Physical Activity XVII Material Properties of Bone XVIII Quiz These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute XIX Quiz XX Load Applied to Bone XXI Injury XXII Cartilage XXIII Articular Cartilage XXIV Fibrocartilage XXV Ligaments XXVI Stress Strain Curve for Ligaments XXVII Synovial Joint XXVIII Types of Synovial Joints XXIX Joint Degradation XXX Quiz XXXI Quiz XXXII Summary Outline of Current Lecture I Muscle II Types of Muscle III Characteristics of Muscle IV Function of Muscle V Groups of Muscle VI Muscle Architecture VII Muscle Volume and Cross Section VIII Fiber Organization IX Fiber Organization X Fiber Type XI Individual Muscle Organization XII Sliding Filament Theory XIII Motor Unit XIV Muscle Contraction XV Muscle Twitch and Tetanus XVI Muscle Attachment XVII Characteristics of a Tendon XVIII Mechanical Model of a Muscle XIX Hill Muscle Model XX Torque XXI Muscle Roll versus Angle of Attachment XXII Roll of Muscle XXIII Agonist versus Antagonist XXIV Net Muscle Actions XXV Factors Influencing Muscle Force XXVI Force Velocity Relationship XXVII Force Length Relationship XXVIII Stretch Shortening Cycle XXIX Muscle Fatigue XXX Strengthening Muscle XXXI Principles of Training XXXII Strength Training and Nonathlete XXXIII Training Modalities XXXIV Injury to Skeletal Muscle XXXV Summary XXXVI Quiz Current Lecture I Muscle a Comprises largest group of tissues in body b 3 types of muscle i Skeletal muscle 1 Voluntary ii Cardiac muscle 1 Involuntary iii Smooth muscle 1 Involuntary c Classified in two diferent ways i Striated or unstriated ii Voluntary or involuntary II Types of Muscle a Skeletal Muscle i Is associated with bony skeleton and consists of large cells that bear striations and are controlled voluntarily b Cardiac Muscle i Occurs only in the heart and consists of small cells that are striated and under involuntary control c Smooth Muscle i Is found in the walls of hollow organs and consists of small elongated cells that are not striated and are under involuntary control III Characteristics of Muscle a Irritability i AKA excitability ii Ability to respond to stimulation iii Stimulation is provided by a motor neuron releasing a chemical neurotransmitter iv Skeletal muscle tissue is one of the most sensitive and responsive tissue 1 Skeletal muscle can be recruited quickly b Contractility i Ability to shorten when it receives sufficient stimulation tension ii Unique to muscle tissue iii Some skeletal muscles can shorten as much as 50 to 70 of their resting length 1 The average range is about 57 for all skeletal muscles c Extensibility i Ability to stretch lengthen beyond the resting length ii Protective mechanism 1 Protect from injury because it is more elasticity iii The skeletal muscle itself cannot produce the elongation by itself 1 Another muscle or external force is required 2 Example pushing another s limb past its resting length iv The elastic material so it can elongate beyond original resting position d Elasticity Flexibility i Ability to return to resting length after being stretched ii Protective mechanism IV Function of Muscle a Produce movement b Maintain postures and positions c Stabilize joints d Other functions i Support and protect visceral organs ii Alter and control cavity pressure iii Maintain body temperature iv Control entrances exits to the body V Groups of Muscles a Muscles typically act in unison not individually i Single muscle cant be activated by itself b Groups of muscles are contained within compartments defined by Fascia c Fascia i Sheet of fibrous tissue ii Compartmentalizes groups of muscles VI Muscle Architecture a Parallel i The fascicles are parallel to the line axis of the muscle ii Flat fusiform strap radiate convergent circular b Pennate i Fibers run diagonally with respect to a central tendon running the length of the muscle ii Unipennate bipennate multipennate VII Muscle Volume and Cross Section a MV m p i Mass of the muscle g ii Density of the muscle g cm2 b Anatomical cross section ACS i A measurement of the cross sectional area perpendicular to the longitudinal axis of the muscle c Physiologic cross section PCS i A sum total of all of the cross sections of fibers in the muscle VIII Fiber Organization a Fusiform i Parallel fibers and fascicles ii High speed of contact force production iii ACS PSC 1 Anatomical cross section ACS 2 Physiologic cross section PCS iv Sartorius biceps brachii brachialis IX Fiber Organization a Penniform Three types b Unipennate i Of one side of tendon ii Semimembranosus c Bipennate i Of both sides of tendon ii Gastrocnemius d Multipennate i Both varieties ii Deltoid e PCS ACS i Penniform fibers have a bigger PCS than ACS X Fiber Type a Type 1 i Slow twitch oxidative ii Red because of high myoglobin content iii Slow contraction times well suited for prolonged low intensity work b Type 2a i Intermediate fast twitch oxidative glycolytic ii Red iii Sustain activity for long period or contract with a burst of force and then fatigue c Type 2b i Fast twitch glycolytic ii White iii Provide rapid force production and fatigue quickly XI Individual Muscle Organization a Myofibril i Contractile element of muscle fiber ii Contain sarcomeres b Sarcomere i Functional unit of skeletal muscle ii Found between 2 z lines connects thin filaments of two adjoining sarcomeres XII Sliding Filament Theory a A F Huxley b Seeks to explain production of tension ine muscle c Myosin and actin i Create cross bridges ii Slide past one another iii Cause the sarcomere to contract XIII Motor Unit a A motor neuron and all the muscle fibers it innervates b Smallest unit of the neuromuscular system c The number of muscle fibers in a motor unit innervated by 1 motor neuron varies i Gastrocnemius 1 2 000 muscle fibers per motor neuron ii Extraocular muscles 1 10 muscle fibers per motor neuron d Ratio of muscle fibers to motor neurons i Afects the precision of movement XIV Muscle Contraction a Resting