EHS 350 Lecture Notes - Lecture 5: Endoplasmic Reticulum, Motor Unit, Muscle Tone
19 Jun 2017
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Muscle twitch single contraction b/c of a simple stimulus latent period - where excitation/contraction occurs - 5 millisec. When ca++ released from sr contraction begins and tension builds up once max tension is reached begin to reabsorb calcium into sarcoplasmic reticulum fewer cross bridges and enter muscle relaxation period. Muscles don"t usually twitch there are graded muscle responses. Tetanus : no relaxation if stimulus increased greatly results in max contraction w/ no tension reduction: motor unit recruitment. Muscle tone - muscles always slightly contract switch from one mu to another to avoid fatigue. Isotonic and isometric isotonic- shortening of muscle isometric- no movement but production of muscle tension. Where to get atp for muscle contraction only store 4 to 6 sec of atp: creatine phosphate lasts 15 seconds. 2) glycolysis anaerobic - don"t need o2 lasts 30 to 40 seconds. 3) aerobic respiration longer lasting method + no lactic acid build up breakdown glucose w/ krebs cycle get 32 atp.
