Chapter 8 Study Guide
1. Name and describe the three different layers of connective tissue in a muscle. Epimysium (sheet of connective tissue that covers a muscle as a whole), endomysium (delicate connective tissue membrane covering the highly specialized skeletal muscle fibers) ,( perimysium (tough connective tissue surrounding fascicles) 2. Myofibrils are composed primarily of two protein filaments called _____________actin__________ and ___myosin_______________________. 3. What is a motor unit? Functional unit composed of a single motor neuron with the muscle cells it innervates 4. Name and describe the parts of a neuromuscular junction.
Motor neurons connect to the sarcolemma of a muscle fiber at a folded motor end plate forming a neuromuscular junction. 5. What do acetylcholine and cholinesterase do? Ach initiates an electrical impulse in the sarcolemma and cholinesterase degrades Ach after it diffuse away from its receptor on the motor end plate 6. Bundles of muscular fibers are called _____fascicles__________________________. 7. The more active your muscles are, the more body heat they release. True or False? True 8. Name the following structures:
A. ______Sarcoplasmic Reticulum________________ Network of membranous channels that surround and run parallel to the myofibrils B. ___Myosin___________________Thick protein filaments within the A-bands C. _________Actin_____________Protein filament that slides inward, toward the middle of a sarcomere, during a muscle contraction D. ____________T-tubule__________ Conducts a muscle impulse deep into a sarcoplasm, to the cisternae E. ________Sarcomere______________The segment of a myofibril between two Z-lines 9. What causes muscles to appear striated? The arrangement of the thick and thin filaments next to each other gives the appearance of striations. 10. Neurotransmitters are stored in vesicles found in the _____synaptic_cleft____________________. 11....