01:119:116 Lecture Notes - Lecture 21: Neuromuscular Junction, Motor Neuron, Osteoporosis
21 Apr 2016
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50. 5 - 50. 6: muscle: contractile tissue that generates movement as a response to nervous system motor output; involved in locomotion, manipulation of env, blood circulation, feeding, peristalsis. Attached to bones via tendons: cords of connective tissue. Most abundant tissue in body: muscle fiber: long cylindrical cell. T (transverse) tubules - infolding of plasma membrane. Sarcoplasmic reticulum - specialized er of muscle cells. Thin filaments: made of actin, tropomyosin and troponin complex (for regulation) Thick filaments: made of myosin molecules, each with a head (interact with thin filaments) and tail (form thick filaments) Actin & myosin: highly organized in muscle cells striped: sarcomere: basic contractile unit; overlapping thin and thick filaments; connect to make a myofibril. Thick filaments (myosin) anchored at m-line. Thin filaments (actin) attached to z-line. Motor unit: motor neuron connected to ~150 muscle fibers; each association = neuromuscular junction.
