Two-dimensional model for understanding the nature of abdominal surface potentials in late gestation

Spontaneous depolarisation and repolarisation due to the ionic currents are the main properties of smooth muscle cells in the uterus. Their functioning as a contractile tissue depends on intercellular electrical and metabolic communication, since only the spreading of action potentials through the whole muscle may result in synchronized contraction. Due to a lack of depolarisation conducting system, the relationship between electrical and mechanical activity of the uterus is determined by the amount of contractile cells being activated at a time. The change in the distribution of electrical charges creates the electric fields that are manifested as an electrohysterogram. On the basis of the two-dimensional model of travelling dipole an attempt to explain the nature of some waveforms of the electrohysterogram is presented. The effects of changed electrode configuration and the distance from the uterus are described