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| The outer sheath of connective tissues that groups muscles together to form fasicles. |
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| Layer of connective tissue that sheaths the muscle fiber specifically composed from reticular fibers. Overlies the sarcolemma. |
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| Outer layer of connective sheath that holds together all the fascicles. Ensheaths the entire muscle. Dense irregular connective tissue |
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| Plasma membrane of the muscle fiber cell. |
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| Tubular infoldings that penetrate through the cell and emerge on the other side. Function to convey electrical signals from the cell surface to its interior- signals the SR when to release the calcium bursts to activate muscle contraction |
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| Long cylindrical protein chains in the cytoplasm that are composed of myosin and actin. Muscle contraction occurs when these slide past each other. |
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| Each segment of a myofibril from one Z disc to the next. The functional contractile unit of the muscle fiber. |
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| Protein disc found in the middle of the I bands that anchors thin filaments at the end of sacromeres |
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| Found on the thin filaments, F unit is composed of G units. Each has an active site that binds to the head of myosin, blocked by the tropomyosin heads. |
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| Protein that makes up the thick filaments. Heads directed outward in helical array around bundle, bind to actin sites. |
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| Light band composed of thin filaments only. |
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| Thick filament portion of sacromere |
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| The Dark band formed by the thick and thick/thin filaments overlying each other. |
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| Regulatory protein that lies in F actin and blocks the myosin binding active sites. |
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| Receptor for Ca++ found on the tropomyosin. Alters configuration of tropomyosin to allow active sites for actin-myosin binding to take place |
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| The point where a nerve fiber meets a muscle fiber. This is the actual synapse. Several points of stimulation. Release of ACh reaches on of 50mil receptors |
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| Another name for the neuromuscular junction. |
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| Released from nerve cells via synaptic vesicles. Acts as the chemical messenger from nerve cell to muscle cell. (SOMATIC MOTOR TO SKELETAL MUSCULAR) |
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| Enzyme that is responsible for breaking down ACH after it has stimulated the muscle cell for contraction. |
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| Excitation-Contraction Coupling |
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Definition
Events that link the action potentials on sarcolemma to activation of myofilaments.
1. AP spreads from NMJ through T-Tubules+Sarcolemma
2. AP open voltage regulated ion gates in T Tubules, allowing calcium into SR, SR opens and calium diffuses into cytosol
3. Calcium bind to troponin, altering configuration of tropomyosin exposing active sites for actin heads to bind. |
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| Autoimmune disease found in women where antibodies attack NMJ and bind ACH receptors together. Muscle fibers remove clusters, making them less sensative to ACh. Leads to double vision, diffiuclaty swallowing, weakness of limbs. Treated with cholinerase inhibitors that prevent breakdown of ACh. |
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| The force exerted by a contracting muscle on an object by the muscle as an organ |
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| One nerve fiber and all the muscle fibers innervated by it. |
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| Muscles contract without changing length and without causing movement |
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| Muscle lengths change during muscle contraction, movement takes place (shortens or lengthens). |
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| Response of a muscle fiber to a single action potential |
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| Thin bodies attach to this, rather than the Z-disc. |
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| Innervation of single-unit smooth muscle cells that conducts electrical signals through the muscle cell. |
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