EXPH 386 Exam 3 Already Rated A+

EXPH 386 Exam 3 Already Rated A+ coordination and integration of the muscles of the body together with the nerves that supply them Neuromuscular system Cell body (soma) action dictates the critical firing rate of the action potential Cell body (soma) contains what code structures involved in replication and transmission of the genetic Are larger cell bodies (somas) associated with higher or lower critical firing rates? higher short neural branches that receive impulses through numerous connections and conduct them toward the cell body Dendrites extends from the cell body to deliver action potentials toward the muscle to the motor endplate Axon Are larger axons associated with slower or faster conduction velocities? faster a lipoprotein membrane that wraps around the axon over most of its length What does the myelin sheath act as? Myelin sheath an electrical insulator that envelops the axon similar to the plastic coating around an electrical wire specialized cells that create or deposit myelin sheath around the axon schwann cells structures that interrupt the myelin sheath every 1 to 2 mm along the length of the axon ranvier what do the nodes of ranvier allow? nodes of they allow the action potential to jump from node to node covering a larger distance, increasing the speed of the action potential saltory when the action potential jumps from node to node because of the uninsulated gaps conduction What would happen if no myelin were present? conduction velocities would be a lot slower since the action potential would have to be conducted along the entire length of the axon multiple extensions of the axon that innervate individual muscle fibers true nerve terminal branches True or False. any one muscle fiber is only going to receive innervation from one nerve terminal branch represents the interface between the end of the axon at the terminal branch and the muscle fiber Motor endplate or neuromuscular junction Break down of skeletal muscle from biggest to smallest (6) 2. bundle of fibers 3. single fiber 4. myofibrils 5. sarcomere 6. contractile proteins what are the skeletal muscles of the body composed of? f ibers which run parallel to eachother Force is directed along what? f iber length variation the fiber's long axis 1. whole muscle multi-nucleated cylindrical cells called few millimeters (eye) to approx. 30 cm (leg) what are the connective tissue layers associated with skeletal muscle? Perimysium Fasiculus Endomysium Epimysium Tendons Periosteum Endomysium a fine layer of connective tissue that wraps each muscle fiber and separates it from the neighboring f ibers surrounds a bundle of up to 150 fibers a large bundle of fibers fasiculus Perimysium a fascia of fibrous connective tissue that surrounds the entire muscle epimysium dense connective tissue, the extension of the epimysium at the ends of the muscle bone's outermost covering; tendons connect the muscle to this covering of the bone The 4 skeletal muscle structures basement membrane sarcoplasm sarcoplasmic reticulum sarcolemma tendons periosteum the muscle fiber membrane; a thin elastic membrane that encloses the fiber's cellular contents Sarcolemma What is the true fiber boundary? the sarcolemma a loose collection of glycoproteins and collagen; outside the muscle fiber Basement membrane contains the nuclei, substrates, and enzymes required for metabolism, the nuclei, mitochondria, and other specialized organelles Sarcoplasm highly specialized network of tubular channels sarcoplasmic reticulum What does the sarcoplasmic reticulum allow for? a wave of depolarization to spread rapidly from the sarcolemma to the inner environment through the T-Tubules to initiate muscle contraction What does the sarcoplasmic reticulum store? true muscle fiber nuclei Myonuclei Where do myonuclei reside? a large concentration of calcium in the muscle fiber directly under the sarcolemma at the periphery of the fiber Myonuclei represent how much of the total nuclear pool? Explain the myonuclear domain hypothesis 85 to 95% normally dormant myoblasts that lie between the basement membrane and the sarcolemma satellite cells upon activation, this cell's functions include muscle regeneration, muscle growth, exercise-induced