BIO 211 Lecture Notes - Lecture 3: Cell Membrane, Perichondrium, Aponeurosis

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In walls of hollow organs (stomach, urinary bladder: not striated, cells are spindle shaped, elongated nucleus, can contract without nervous system stimulation. Insertion: movable bone: origin: immovable (less movable) bone, attachments are direct or indirect, direct: epimysium fused to periosteum of bone or perichondrium of cartilage. Increase muscle fiber"s surface area sarcomere: triad relationships, t tubules conduct impulses deep into muscle fiber; every sarcomere, integral proteins protrude into intermembrane space from. T-tubule and sr cistern membranes- act as voltage sensors: sr foot proteins: gated channels that regulate ca2+ release form sr cisterns. I bands shorten; z discs closer; h zones disappear; a bands move closer together (lengths stay the same) Physiology of skeletal muscle fibers: for skeletal muscle to contract, activation (at neuromuscular junction, must be nervous system stimulation, must generate action potential in sarcolemma, excitation-contraction coupling, action potential propagated along sarcolemma. Ionic conditions of resting state restored by na+-k+ pump.