Worksheet (Muscular System)

SKELETAL MUSCLE WORKSHEET MATCHING I. Match the proper structure to the statement. A. B. C. D. E. F. Actin Endomysium Epimysium Fascicles Motor end plate Motor unit G. Myosin H. Myofibrils I. Neuromuscular junction J. Neuromuscular cleft K. Perimysium L. Sarcolemma M. N. O. P. Q. Sarcomeres Terminal cisternae Transverse tubules Triad Tropomyosin 1. Primary protein of thick filament G 2. Connective tissue surrounding each fascicle K 3. Cell membrane of muscle fiber L 4. Bundles of muscle fibers D 5. Functional unit of myofibrils; extend from Z line to Z line M 6. Connective tissue surrounding the entire muscle C 7. Threadlike structures in muscle fibers; composed of thick and thin filaments H 8. Site where motor neuron and muscle fiber meet i 9. Pocket of sarcolemma in which motor neuron's end bulbs (buton) fits E 10. Membranous channels that extend inward from sarcolemma and pass through fiber O 11. Area of sarcoplasmic reticulum in which Ca++ is stored N 12. The motor neuron and all the muscle fibers it innervates F 13. Connective tissue which surround each muscle fiber B 14. Contains one t-tubule and two terminal cisternae P 15. Primary protein of thin filament A MATCHING II. Match the following statement to the appropriate part of a sarcomere. A. A band B. I band C. H zone D. M line E. Z line 1. Located in the center of the I band E 2. Contains both thick and thin filament A 3. Area consisting of only thick filament C 4. Appears as dark striations under the microscope A 5. Line in the center of the A band D 6. Disappears during full contraction C 7. Width narrows during full contraction B 8. Area consisting of only thin filament B 9. Contains crossbridges A 10. Width does not narrow (unchanged) during full contraction A MATCHING III. Match the following statements to the appropriate fiber type (Fast Twitch or Slow Twitch). ___Slow twitch____ 1. Higher number of capillaries surrounding this type muscle fiber. _Fast twitch______ 2. Type II fibers _Slow Twitch______ 3. Low ATPase activity _Fast Twitch______ 4. High cross bridge cycling rate _Fast Twitch______ 5. High concentrations of glycolytic enzymes Slow Twitch_______ 6. High number of mitochondria Fast twitch_______ 7. Less efficient _Fast twitch______ 8. High Vmax Fast twitch_______ 9. Relies on anaerobic energy system _fast twitch______10. Recruited at high exercise intensities Place the following events of excitation-contraction coupling in sequential order (1-14). ___4___ EPP is transmitted down sarcolemma __2____ Release of acetylcholine into neuromuscular cleft __3____ Acetylcholine binds with receptors __7____ Ca++ binds with troponin ___14___ Ca++ pumped into terminal cisternae ____9__ Actin binds with energized myosin crossbridge ____10__ Powerstroke ___8___ Tropomyosin is moved to uncover myosin-binding sites on actin ___13___ Hydrolysis (splitting) of ATP and re-energizing of myosin crossbridge ___1___ Action potential down axon of motor neuron ___11___ ATP binds to crossbridge ___12___ Detachment of actin and myosin ____6__ Ca++ is released from terminal cisternae of sarcoplasmic reticulum __5____ EPP is transmitted down t-tubules Fill in the Blank. 1. Type of contraction occurring when force is produced but muscle lengthens Eccentric contraction 2. Type of muscle contraction also known as a static contraction Isometric 3. Loss of muscle mass due to disuse Atrophy 4. Mechanical response of a muscle to a single electrical stimulus Twitch 5. Phase of a muscle twitch considered to be longest in duration regardless of fiber type Relaxation 6. A blending of single contractions into a single sustained contraction Fused Tetanus 7. Primary fiber type of track sprinters Fast twitch 8. The fastest skeletal muscle fiber type in humans IIX 9. Neurotransmitter released at the neuromuscular junction. Acetylchline TRUE / FALSE. 1. 2. 3. 4. 5. 6. 7. Type I fibers appear the lightest in color after staining for ATPase activity false Ca++ binds to myosin crossbridges false Troponin covers the myosin-binding sites on actin false ATP is required for detachment of actin and myosin true Type IIx fibers are considered to be intermediate in oxidative capacity false A fast-to-slow fiber shift would occur with resistance training true Fine motor skills are accomplished by muscles with a high innervation ratio false INCREASE / DECREASE / NO EFFECT. __I___ 1. Effect of increased % fast twitch fibers on power output. ___D__ 2. Effect of decreasing Ca++ in sarcoplasm on the number of crossbridges bonds. ___I__ 3. Effect of increasing stimulus magnitude on force production. ___I__ 4. Effect of increasing stimulus frequency on force production. ___I__ 5. Effect of a slight increase in length over rest on force production. ___I__ 6. Effect of increased testosterone on muscle mass. ____D_ 7. Effect of increased H+ and Pi on muscle force production. ___I__ 8. Effect of synchronization on muscle force production. __D___ 9. Effect of increased stimulation of Golgi tendon organs on force production. _I____10. Effect of increased stimulation of muscle spindle on force production.