BISC 3221 Chapter Notes - Chapter 9: Trapezius Muscle, Muscle Spindle, Buccinator Muscle

• School: Fordham University
• Department: Biological Sciences
• Course: BISC 3221
• Professor: Craig Frank

Document Summary

1: basic properties of skeletal, cardiac, and smooth muscle tissue. Microanatomy of skeletal muscle fibers: sarcolemma: cell membrane of skeletal muscle fiber, sarcoplasm: cytoplasm of skeletal muscle fiber. Change in membrane potential generate action potential release of ca: action potentials continue to be generated until acetylcholine esterase removes ach. 4: sr reabsorbs ca, [ca] in sarcolemma declines, troponin-myosin complex returns to normal position, no cross bridge = no sliding = muscle relaxation. Muscle hypertrophy: exercise increases activity of muscle spindles, may enhance muscle tone, repeated exhaustion = muscle fibers develop more myofibrils, mitochondria, glycolytic enzymes, larger glycogen reserves, hypertrophy of the stimulated muscle results. Muscle atrophy: not stimulated enough, loss of muscle tone and mass, atrophy: reduction in size tone, power of skeletal muscle. Initially reversible, but dying muscle fibers cannot be replaced; in extreme atrophy the damage is permanent.