mammalian muscle properties

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Mammalian Muscle Properties. Madden et al. IEEE J. Oceanic Engr. 29: 706, 2004. Skeletal muscle features. Muscle surpasses artificial actuators only in the fuel delivery Linear actuation Adapted for intermittent duty and stiffness (compliance) control - PowerPoint PPT Presentation

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  • Mammalian Muscle PropertiesMadden et al. IEEE J. Oceanic Engr. 29: 706, 2004

    Property

    Typical

    Maximum

    Strain (%)

    Strain rate (%/s)

    Stress (Mpa)

    20

    0.1 (static)

    >40

    >50

    0.35

    Work Density (kJ/m3)

    Specific Power (W/Kg)

    Efficiency (%)

    8

    50

    40

    284

    40

    Modulus (MPa)

    Density (kg/m3)

    Cycle Life

    40

    1037

    >109

  • Skeletal muscle featuresMuscle surpasses artificial actuators only in the fuel delivery Linear actuationAdapted for intermittent duty and stiffness (compliance) controlVersatile force control: recruitment + stiffness modulation (w/o feedback) Madden et al. IEEE J. Oceanic Engr. 29: 706, 2004

  • Muscle

    or Force

    or Length

    Shortening: concentriccontraction causes too muchoverlap between ACTINand MYOSIN

    Lengthening: eccentriccontraction causes too littleoverlap between ACTINand MYOSIN

    [figures: sources unknown]

  • Tendons & Ligaments

    Rupture

    Full FibreRecruitment

    Straightening Fibres Out (Toe Region)

    Fibres Start to ExperiencePermanent Damage

    Yield

    Toe Region to Fibre Recruitment Process with increasing

    HysteresisLoop

  • Hill model : Force dependence on contraction velocity

  • MotorSpecific PowerErgs/s-gForce(dynes)Velocitymm/sActin Polymerizationmtubule polymerization109

    10810-7

    10-71.02

    Myosin IIKinesinSpasmoneme10810710910-610-710-34180,000CarStriated muscleBacterial FlagellaLimulus aroscomeEukaryote FlagellaMitotic spindle106106106104102

    10-6

    10-5

    100 Hz10

    2

  • McKibben muscle

  • McK musclesSteel braid wrapped around a rubber tube.Crimped at ends

  • 20N/g

  • Testing

  • Antagonistic pairs for smooth torque

  • Friction in the meshFilament on filament friction (no sliding relative to the tube)

  • Properties of McK muscles1. Fstatic ~ CSA (pro2)2. Fstatic ~ P3. Fstatic is independent of initial length4. Fstatic max ~ 1/ao5. Fstatic ~ 1/e

  • Molecular Springs & RatchetsSpasmoneme of the VorticellaAcrosomeActin polymerization

    Mahdevan, L : Science, 288: 95, 2000.

  • Spasmoneme of the Vorticella

  • Actin SpringAcrosome needs to penetrate egg jelly. Spring is super-coiled- held twisted by scruin.Ca++ Ds scruin

  • Supramolecular ratchetsPawl and ratchet analogy of actin polymerizationHow controlled? In quiescence, profilin is the shut-off switch. Stimulus such as pH D in presence of actin monomers can start.Listeria rides this bus

  • Overall energy balance

  • Conducting polymersLarge molecular deformations (strains) induced by currentReversible Change in oxidation state

  • How does muscle fatigue?Test of a skinned muscle fiber from EDL of rat.Can activate by direct stimulation of any step in the cascade. Pederson, TH: Science 305: 1144, 2004

  • F1 ATPase: A rotary motorCan either make or break ATP, hence is reversibleTorque of 40 pN-nM; work in 1/3 rev. is 80 pn-nM (40 * 2p/3) equivalent to free energy from ATP hydrolysisCan see rotation by attaching an actin filament

  • Rotary Cellular MotorsThe rotary mechanism of ATP synthase , Stock D, Gibbons C, Arechaga I, Leslie AGW, Walker JE CURRENT OPINION IN STRUCTURAL BIOLOGY ,10 (6): 672-679 DEC 20002. ATP synthase - A marvellous rotary engine of the cell, Yoshida M, Muneyuki E, Hisabori T NATURE REVIEWS MOLECULAR CELL BIOLOGY 2 (9): 669-677 SEP 20013. The gamma subunit in chloroplast F-1-ATPase can rotate in a unidirectional and counter-clockwise manner Hisabori T, Kondoh A, Yoshida M FEBS LETTERS 463 (1-2): 35-38 DEC 10 19994. Constructing nanomechanical devices powered by biomolecular motors.C. Montemagno, G Bachand, Nanotechnology 10: 225-2312, 1999.

  • Comparative motors

  • When L>> x, the chain has many bends and is always crumpled in solution the FJC model applies, with each link approximated as 2 x, and perfectly flexible joints.To count all possible curved states in a smooth-bending rod in solution- its a WLC- supercoiling is possible.

  • F1 ATPase: A rotary motorCan either make or break ATP, hence is reversibleTorque of 40 pN-nM; work in 1/3 rev. is 80 pn-nM (40 * 2p/3) equivalent to free energy from ATP hydrolysisCan see rotation by attaching an actin filament

  • (www.sciencemag.org/feature/data/1049155.shl).

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