Muscle Fatigue by Rachel Reiser https://padlet.com/rachel_e_reiser/naioeci99ysm BIOM2012 en-us 2017-09-21 01:27:38 UTC 2024-05-31 05:46:36 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Basketball.png Muscle cells rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/189581518
  • Called fibres
  • Large in comparison to other cells
  • 'myo' = muscle
  • 'sarco' = flesh
    • ]]>     2017-09-21 01:32:49 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/189581518     Muscle types rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/189581687
  • Striated (striped)
    • cardiac (auto-regulated)
    • skeletal (strength, speed and agility required)
  • Smooth (visceral)

    • In all muscle types, contraction is initiated by a rise in intracellular ionised calcium concentration in response to electrical and/or pharmaco-chemical stimulation.
    ]]>     2017-09-21 01:34:10 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/189581687     Terminology rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/189582178
  • Sarcoplasm
  • Myoplasm
  • Cytoplasm
  • Intracellular
  • ATPase: the active provess by which energy in the form of ATP hydrolysis is used to translocate a certain ion across a membrane against its concentration gradient.
    • ]]>     2017-09-21 01:38:54 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/189582178     Functions of muscle in mammals rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/189582457 1. Locomotion
    2. Respiration
    3. Blood circulation
    4. Digestion
    5. Excretion
    6. Reproduction
    7. Vocalisation
    8. Vision]]>     2017-09-21 01:41:02 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/189582457     Structure of Skeletal Muscle rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193243588
  • Fibres extend from tendon to tendon
  • Multinucleated cells with peripheral nuclei

    • ]]>     2017-10-03 00:57:48 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193243588     Resting Membrane Potential rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193243653 The potential at which there is no net current across the membrane --> the sum of the currents carried by different ions is equal to zero.

    The Goldman-Hodgkin-Katz (GHK) equation allows EM to be calculated from the concentration differences of K+, Cl- and Na+ and their relative permeabilities.
    • K+, Cl- and Na+ are the most permeable ions and therefore have the greatest effect on EM. 


    ]]>     2017-10-03 00:58:21 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193243653     Muscle Contraction rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193245331
  • Muscle fibres are innervated by a single motor neuron
  • Motor unit = basic unit of motor function = one motor neuron together with all the muscle fibres it innervates.
  • Fine movement control is generally mediated by 3-6 muscle fibres (ocular muscles) whereas powerful contractions are created by over 2000 fibres (quadriceps) 
    • Strength of contraction is generally mediated by the amount of muscle fibres innervated.

    • ]]>     2017-10-03 01:11:34 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193245331     Classes of Fibres rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193245854 2017-10-03 01:15:07 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193245854 Tetani rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193247085
  • Frequent stimulation of twitch fibres results in tetanus
  • APs are "all-or-nothing" events therefore they cannot fused together.
  • The [Ca2+] transient responses do fuse 
  • This is shown in the complete or incomplete fusion of the 'twitch' force responses
  • Completely fused force response = complete/fused tetani
  • Incompletely fused force response = incomplete/unfused tetani

    • ]]>     2017-10-03 01:24:23 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193247085     Type of muscle contraction rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193253438
  • Isometric - constant length of muscle during contraction, no external work is generated (work = force x distance)
  • Isotonic - muscle produces mechanical work after shortening under constant load
  • Eccentric - muscle stretched while contracting
  • Isokinetic - muscle shortens at constant velocity
  • Auxotonic - muscle shortens at variable velocity
    • ]]>     2017-10-03 02:22:00 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193253438     Muscle Fatigue rachel_e_reiser https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193268378 The decline seen in peak force production and muscle output associated with intense or prolonged muscle activity.

    Depends on:
    • Intensity and duration of stimulation
    • Muscle fibre type

    Types of Muscle Fatigue
    • High frequency fatigue
      • Fast onset
      • Fast recovery
    • Metabolic fatigue
      • Less force produced due to less Ca2+ released
    • Long duration fatigue
      • Caused by stretching the muscle while contracting (eccentric damage)
      • Raising intracellular [Ca2+] too much for too long
    ]]>     2017-10-03 04:45:40 UTC https://padlet.com/rachel_e_reiser/naioeci99ysm/wish/193268378