9.14 From Genes and Molecules to Organs and Organisms: Heart

摘要: Mechanical contraction of the heart and its blood-pumping action are activated synchronized by a wave electrical excitation. Propagation excitation involves potential (AP) generation cardiac cells conduction in multicellular tissue. AP is accomplished through complex, nonlinear interactions between membrane ion channels, transmembrane voltage, dynamically changing ionic milieu cell. propagation achieved flow charge from cell-to-cell intercellular gap junctions. As described this chapter, process strong within across scales molecular structure function properties junctions, subcellular organization cell, tissue architecture. At whole-heart scale, normal generated right atrium sino-atrial (SA) node transmitted to ventricles atrio-ventricular (AV) node. It then spreads rapidly via specialized (Purkinje) system establish broad wavefronts that propagate synchroneously endocardium epicardium both ventricles. Abnormal activity can originate at any scale system, possibly leading rhythm irregularities could be fatal (cardiac arrhythmias one most frequent causes morbidity mortality human population).