APA 2312 Lecture Notes - Lecture 2: Myopathy, Action Potential, Myelin
4 Apr 2016
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T-tubules cell membranes that extend to the inside of the muscle cell. They go into muscle ibre/cell, to reach all myoibrils at same ime. Endomysium connecive issue surrounding a muscle ibre. Sarcolemma cell membrane around the muscle ibre. The sarcolemma keeps paricles either in or out of the cell. Movement of ions across the membrane depends on the ion concentraion, their charge, and size. When the membrane is in rest, resing potenial diference of -70mv. Transmits signal to sr which releases calcium into sarcoplasm. Muscle triad: terminal cisternae, t-tubule, terminal cisternae (almost no space in between) A muscle contracion begins when stored calcium ions are released into the sarcoplasm. Ions difuse into individual contracile units called sarcomeres. A band without overlapping areas h zone. Slowly release following contract, allowing muscle to return to regular length. Cross-secional arrangement of thin and thick ilaments at diferent points throughout a sarcomere. F-acin strand: twisted strand of 300-400 globular molecules of g-acin.
