Bio 203 Objectives Essay

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Lecture 10 1. Describe the functions of the various types of muscle * Skeletal- limb movement * Cardiac- heart movements * Smooth- movements of hollow organs 2. Describe the involvement of connective tissue in a skeletal muscle * Endomysium- surrounds and fills up spaces between individual muscle fibers * Perimysium- ensheaths muscle fascicles (bundles of muscle fibers) * Epimysium- ensheaths the whole muscle 3. Name the components of a skeletal muscle fiber and describe their function * Sarcoplasm- cytoplasm * Sarcolemma- plasma membrane * T-tubules- inward extensions of the sarcolemma * Mitochondria- provide ATP * Sarcoplasmic reticulum- endoplasmic
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Describe how excitation-contraction coupling in cardiac muscle is slightly different * The contraction is much more dependent on calcium ions in the external medium than the contraction of skeletal muscle * This is because calcium enters the muscles through the t-tubules which acts to trigger the release of more calcium ions from the sarcoplasmic reticulum 10. Describe muscle relaxation * An ATP driven calcium pump in the membranes of the sarcoplasmic reticulum removes the calcium ions from the sarcoplasm back into the sarcoplasmic reticulum where it binds to the protein calsequestrin * Myosin binding sites on actin are replaced blocked by tropomyosin 11. Explain rigor mortis * When a person dies calcium leaks into the muscle fibers causing the myosin binding sites to be exposed and the muscle contracts * The muscle cannot relax because there is no ATP so the muscles stay contracted until lysosomal proteases start to break down muscle proteins 12. List the processes and substances that provide the energy for contracting muscle * ATP in muscle cell * Creatine phosphate * Glycolysis * Krebs cycle * Oxidative phosphorylation 13. Explain why an athlete might take a creatine dietary supplement and how this relates to the phosphagen system * To build up the amount of creatine phosphate in

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