BIOD27H3 Lecture Notes - Lecture 17: Endoplasmic Reticulum, Myofibril, Motor Neuron

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Skeletal attached to bones or our skeleton by collagen known as tendons positions and moves the body or appendages(locomotion) only these contract to a signal from somatic m motor neuron cannot initiate own contraction. Origin point of muscle-bone attachment closest to trunk. Insertion is usually more mobile and is the point of muscle bone attachment more distal or distant from the trunk. Group of muscle cells function together and have many nuclei and are arranged in parallel connective tissue encases lots of fibers together. Groups of adjacent fibers are contained in fasicles. (collagen, elastic fibers, nerves and blood vessels are found between the fasicles) Components of muscle fibers myofibrils, which contain thick and thin filaments(myosin and actin) The contractile machinery: arcolemma = cell membrane, transverse tubules (t-tubules) = invaginations of the sarcolemma, sarcoplasm = cytoplasm (contains mitochondria and glycogen for muscle contraction) Releases ca during muscle contraction: mitochondria : provides atp for muscle contraction.