BIO 203 Lecture Notes - Lecture 14: Skeletal Muscle, Neuromuscular Junction, Axon
14 Dec 2016
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Document Summary
Skeletal- fibers are large, have stripes, striated muscle fibers. Cardiac- fibers are striated, smaller fibers, branched and. Cells bundled into fassicles surrounded by connective tissue. Tendon, nerve and blood vessels, connective tissue, muscle fassicle- bundle of fibers. T-tubules- bring action potentials into interior of muscle fibers. Triad- site where t-tubules and sarcoplasmic reticulum interact. A band, i band , z disk (middle of i band), m line (middle of a band) Thick filaments- a band, thicker and darker, myosin tail, hinge region, myosin heads (binding sites for atp and actin) Thin filaments thin, two strand twisted together, actin chain. Muscle relaxed, sarcomere shortens with contraction, muscle contracted h zone and i band both shorten, while a band remains constant. Relaxation: release of tension, lack of contraction, natural state is relaxed. Excitation- motor neuron releases a signal and acetylcholine on the muscle fiber. Ach is released from the somatic motor neuron. Ach binds to receptors on the sarcolemma ****
