Details Title: 230 Description: Part III of III Total Flash Cards: 14 Created: 12/08/2008 17:50:25		New Users: To study from this flashcard set, or to create your own your own study flash cards, REGISTER HERE. Existing Users: CLICK HERE. Additional Biology Flashcards
Cards in this set: Term Threshold Stimulus Definition Minimal strength stimuli required to initiate contraction Term Periods of Muscle Twitch (Force over Time curve) Definition Latent Phase(impulse travel; ca++ release) Contraction Relaxation Term Summation/Twitch types (3 types) Definition Complete relaxation between twitches Wave summation: incomplete tetanus (partial relaxation) Complete tetanus (increasing strength w/ each successive twitch; no relaxation. Sustained or Tetanic contraction). Most common in muscles. Term Recruitment ~ Multiple Motor Unit Summation Definition Motor axons connect to mx muscle fibers; fewer fibers per axon=greater control (such as eye); more fibers per axon associated with larger muscles. ~ As intensity of stimulation increases, additional motor units are 'recruited' for action, until all available are at work. Term Asynchronous Motor Summation Definition Different sets of muscle fibers stimulated so that they may be alternated ('relay team'); see graph in notes. If properly timed, force level is maintained throughout use of alternating muscle units. Term Muscle Tone Definition Sustained contraction, essentially. Associated with collapse upon loss of consciousness. Term Optimal contraction length Definition Not overly compressed or extended (think of sarcomere). Term Cause of Muscle soreness Definition Lactic Acid buildup, damage to muscle fibers. Term All/None Response Definition Muscle Twitches develop same force per twitch, however in a whole muscle, not all fibers are stimulated at once, and the frequency of impulses regulates strength. Term Type 1 Fibers Definition Slow; Red (myoglobin); Always oxidative/aerobic, fatigue resistant. More mitochondria Term Type II-A Fibers Definition Fast, White (less vascular), less mitochondira and respiratory capacity. Greater SR, faster ATPase, rapid contraction. Either Glycotic (fatigue-able due to lactic acid buildup and ATP supply) OR Oxidative (fatigue resistant). Term Type II-B Fibers Definition Intermediate; fast(er) and w/ moderate oxidative capacity. Term Muscle Fiber Composition Definition All muscles have combined fiber types, but in different proportions reflecting specialized functions. ***Long distance runners up to 90% Type I Term Muscle Use and Disuse; Hypertrophy + Atrophy Definition Hypertrophy: forcefully exercised, enlargement due to additional filaments but no new muscle fibers. Atrophy: Disuse, muscles shrink. Mitochondria levels drop, capillary networks/respiratory capacity diminished. Can shrink 50% in size in few months.