ABSTRACT
J. B. Corliss, based on extensive submarine research, suggests that life originated in shallow Archean seas in consequence of the eruption of magma through cracks on the earth's crust. According to this idea submarine hot springs provided the conditions for the generation of life about 3.6 billion years ago. A simple model of cell-to-cell communication is represented by two adjacent cells separated by extracellular fluid. A chemical signal released by cell A can induce changes in cell B if this cell is provided with specific receptors at the level of the surface cell membrane. Adaptative changes in junctional conductance are probably involved in the maintenance of different values of membrane potential inside the same cell population. In heart, for instance, the membrane potential in pacemaker cells of the sinoatrial node is about 60 mV, whereas in the right atrium values of 75 to 80 mV are found.
