Muscles 3 types Skeletal voluntary somatic NS supplies Smooth involuntary Autonomic NS supplies Cardiac involuntary Autonomic NS supplies Neuromuscular junction synapse that is in between muscles and nerves Skeletal muscle cell or muscle fiber cell fiber Myofiber muscle cell Sarc root applies to muscle lemma membrane Sarcoplasmic reticulum stores CA ions Sarcolemma muscles membrane T tubule conducts action potential towards the interior of the muscle call Triad 2 sarcoplasmic reticulum and 1 t tubule 3 muscle proteins Contractile proteins Actin sliding filament mechanism thin myofilament refers to the movement of actin over myosin contains binding sites for myosin Myosin thick thick myofilament Regulatory proteins Tropomyosin filamentous protein acts as a blind fold over actin binding sites for myosin Troponin globular protein tacks down tropomyosin over actin Titin associated with thick myofilaments holds myosin molecules in place Structural proteins Muscle units and definitions Neuromuscular junction the space between a nerve cell and the muscle cell its is supplying Motor unit 1 nerve cell and all of the muscle calls it supplies smaller motor units 1 motor neuron supplies few muscle cells large motor units 1 motor neuron supplies hundreds or more muscle cells hierarchy of muscle structure whole muscle epimysium connective tissue covering whole muscle perimysium surrounds each fascicle bundles or fascicles they are collects of myofibers endomysium connective tissues covering around each cell Sarcolemma Inner structure of myofiber or muscle cells Myofibril inside the sarcolemma Hierarchy of microstructure of a muscle Muscles units are organized from smallest to largest Actin and myosin myofilament proteins Sarcomere made up of actin and myosin contractile units of a muscle sliding filament mechanism actin sliders over myosin Myofibril contain many sarcomeres Muscle fiber contains many myofibrils Whole muscle consists of many fascicles Fascicle bundle of muscle fibers Connective tissue covering Endomysium CT covering a muscle call or muscle fiber Perimysium CT covering the fascicle Epimysium CT covering the whole muscle Excitation contraction coupling Action potential moves across the sarcolemma and moves inside the myofiber though the t tubules Causes release of Ca stored in sarcoplasmic reticulum Ca binds to troponin The troponin lock tropomyosin handle is removed Actin binding site for myosin are exposed Myosin heads can bind to actin Muscle contracts Cross bridging can occur contact of actin with myosin Cross bridge cycle Cross bridge formation The power strokes Cross bridge detachment ATP is necessary Cocking bent position of the myosin head Types of muscle Skeletal Skeletal voluntary actives movement straited and multinucleated Smooth involuntary controlled by ANS nonstriated Cardiac involuntary controlled by ANS straited Straited Multinucleated Excitable Voluntary somatic NS Conscious movement Smooth Cardiac Nonstriated Central nucleus Excitable Involuntary ANS autonomic NS Found internal organs and viscera Striated Central nucleus Excitable Involuntary autonomic NS Contractility of cardiac myofiber