细胞功能.ppt

影响横纹肌收缩效能的因素肌肉的收缩形式: 等 长收缩(isometric contraction) : 等 张收缩(isotonic contraction) : Resting tension Non-contractile and connective tissue in muscle itself Tendon ?张力不变,长度减小§长度不变,张力增加 Isometric contraction isotonic contraction Isotonic Isometric 负荷的形式(1) 、前负荷( preload ) :肌肉收缩前已经存在的负荷,它使肌肉在安静时即有初长度; (2) 、后负荷( afterload ) 肌肉收缩后方能“感觉”到的负荷; Isometric contraction isotonic contraction Preload (长度-张力曲线) Transducer S Move up or down to change preload (initial length) F1 F3 Initial length & preload F2 1. Passive tension is the tension developed by simply stretching a muscle to different lengths ( think of a rubber band). 2. Passive tension is determined by preload and the elasticity of the muscle itself. The active tension is maximal when there is maximal overlap of thick and thin filaments and maximal cross-bridge 2 to ? m in vivo Preload (长度-张力曲线)