MUSCLE PHYSIOLOGY Dr. Adelia Handoko, M.Si Departmemt of Physiology Jember University
References: Boron WF, Boulpaep E, 2012. Medical physiology. 2nd ed. A cellular and molecular approach. Updated ed. Elsevier Saunders, Philadelphia. Ganong WF, 2005. Review of medical physiology. 22nd ed. McGraw Hill, New York. Guyton AC, Hall JE, 2011. Textbook of medical physiology. 12th ed. WB Saunders Co, Elsevier Inc. Sherwood L, 2010. Human Physiology from Cells to Systems. 7th ed. Brooks/Cole, Cengage Learning. Silverthorn DU, 2010. Human Physiology– An Integrated Approach 5th ed. Pearson Education Inc. San Francisco, CA 94111.
Learning Objection • Structure of Skeletal Muscle • Levels of organization in muscle • Thick- and thin-filament composition • Molecular Basis of Skeletal Muscle Contraction • Sliding filament mechanism • Excitation–contraction coupling • Motor Unit • Neuromuscular Junction • Slow & fast twitch muscle fibers
Primary motor cortex/ area Brodmann 4/ precentral gyrus Pyramidal tract Motor neuron A Muscle fiber Neuromuscular junction
Motorneuron Motoric nerve NMJ Muscle fiber Spinal cord
anterior motor-neuron A motoric nerve Neuromuscular junction Sarcolemma (membrane of muscle fiber) Cisternae of Sarcoplasmic reticulum Calcium release Muscle contraction
A musculoskeletal system (also known as the loco-motor system) is an organ system that gives animals (and humans) the ability to move using the muscular and skeletal systems.
Physiology of Muscle Muscle cell is called MYOCYTE
Muscle tissue types Somatic nerve innervations Autonomic nerves innervations Autonomic nerves innervations Striation voluntary Striation unvoluntary No striation unvoluntary • Skeletal • Cardiac • Smooth
Voluntary is influenced by mind / thought voluntary muscle, under the control of the will and is generally attached to the skeleton. Several skeletal muscles is not attached to the skeleton
Skletal Muscle (Despopoulos & Silbernagl, 2003)
Levels of organization in a skeletal muscle. (Sherwood , 2007)
Myosin Structure (Despopoulos & Silbernagl, 2003)
Myosin Structure (Sherwood , 2007)
Actin Structure (Sherwood , 2007)
Head of myosin ceasesbinding to the thin filament Relaxation phase Calcium leave troponin C, because calcium pumped back into cisternae
Contraction phase Ganong W F: Review of Med. Physiol. Calcium bind TROPONIN C Actin binding site opened
Wolverine Zaman NOW Wolverine Zaman OLD
MUSCLE PLASTICITY Muscle memory and a new cellular model for muscle atrophy and hypertrophy Kristian Gundersen Journal of Experimental Biology 2016 219: 235-242; doi: 10.1242/jeb.124495
Oxidative stress and disuse muscle atrophy Scott K. Powers, Andreas N. Kavazis, Joseph M. McClung Journal of Applied Physiology Published 1 June 2007 Vol. 102 no. 6, 2389-2397 DOI: 10.1152/japplphysiol.01202.2006
Rigor mortis (death stiffness) is one of the recognizable signs of death that is caused by a chemical change in the muscles after death, causing the limbs of the corpse to become stiff (rigor) and difficult to move or manipulate.
In humans it commences after about 2-3 hours, reaches maximum stiffness after 12 hours, and gradually dissipates until approximately 72 hours (3 days) after death.
After death, respiration in organisms ceases to occur, depleting the corpse of oxygen used in the making of Adenosine triphosphate (ATP). ATP is no longer provided to operate the SERCA pumps in the membrane of the sarcoplasmic reticulum, which pump calcium ions into the terminal cisternae.
This causes calcium ions to diffuse from the area of higher concentration (in the terminal cisternae and extracellular fluid) to an area of lower concentration (in the sarcomere), binding with troponin and allowing for cross-bridging to occur between myosin and actin proteins.
MOTOR UNIT is the motor nerve and all of the fibers it innervates. Different muscles have different innervation: ratios- 1:10 for ocular muscles- smaller motor units 1:10,000 for quadriceps muscles - larger motor units
Neuromuscular junction & Skeletal muscle
Hubungan antara Saraf motorik vs muscle fiber adalah : Neuro-muscular junction