PHGY 209 Chapter Notes - Chapter --: Postganglionic Nerve Fibers, Myasthenia Gravis, Myostatin

• School: McGill University
• Department: Physiology
• Course: PHGY 209
• Professor: Ann Wechsler

Document Summary

9. 1 structure of muscle: striated muscle: distinct series alternating light & dark bands perpendicular to long axis, cardiac and skeletal muscle are striated, not smooth. Connective tissue structure: muscle: skeletal muscle fibers bound together by connective tissue, attached to bones by tendons: collagen fibers (connective tissue) Individuals fiber sometimes extend entire muscle length, but most shorter and oriented at angle. Sarcomere structure: sarcomere: one unit of repeating pattern of thick & thin filaments, a band: wide dark band of thick filament in middle of sarcomere, z line: lines defining the limits of the sarcomere. 9. 2 molecular mechanisms of skeletal muscle contraction: contraction: activation of cross-bridges (force-generating sites in muscle fibers), not necessarily shortening. Events at neuromuscular junction: action potential of motor neuron depolarizes plasma membrane by opening the. 9. 3 mechanics of single-fiber contraction: tension: force exerted on object by contracting muscle, load: force exerted on muscle by object (opposing force to tension)