论文部分内容阅读
电生理研究表明:哺乳动物心肌的兴奋性决定于各种离子跨膜运转活动(离子流通道)。心肌细胞的动作电位是由通过细胞膜的一系列离子(钠、氯、钙、钾)扩散或离子流所产生。例如:快速除极期(O 相),是由于钠离子快速内流所引起,心肌缓慢复极期(2相)是由于细胞外钙离子通过慢通道缓慢而持久的内流而引起。在心肌传导组织的电生理活动中,钙流也起着重要用作:钙离子浓度增高时,心肌自律性及传导性增强;浓度降低时则传导减慢,自律性受到某种程度的抑制。此外,钙离子还影响心肌的收缩作用。实验证明,当细胞内钙浓度达到
Electrophysiological studies have shown that the excitability of mammalian myocardium depends on various ion transmembrane activities (ion channel). The action potential of cardiomyocytes is produced by the diffusion or ion flux of a series of ions (Na, Cl, Ca, K) that pass through the cell membrane. For example, the rapid depolarization phase (O phase) is caused by rapid influx of sodium ions. The slow repolarization phase (2 phases) of the myocardium is caused by a slow and persistent influx of extracellular calcium ions through the slow channel. Calcium flow also plays an important role in the electrophysiological activity of cardiac conduction tissue: when calcium concentration is increased, myocardial self-regulation and conductivity increase; when concentration decreases, conduction slows and autonomicity is inhibited to some extent. In addition, calcium ions also affect myocardial contractility. Experiments show that when the intracellular calcium concentration reached