Systole heart beats—is cued by messages from the brain, reflecting the brain's responses to conditions of the body, such as pain, emotional stress, level of activity, and to ambient conditions including external temperature, time of day, etc. Electrical systole opens voltage-gated sodium, potassium and calcium channels in cells of myocardium tissue. Subsequently, a rise in intracellular calcium triggers the interaction of actin and myosin in the presence of ATP which generates mechanical force in the cells in the form of muscular contraction, or mechanical systole. The contractions generate intra-ventricular pressure, which is increased until it exceeds the external, residual pressures in
Theology of the Body Theology of the Body Theology of the Body is the topic of a series of 129 lectures given by Pope John Paul II during his Wednesday audiences in St. Peter's Square and the Paul VI Audience Hall between September 5, 1979 and November 28, 1984. It constitutes an analysis on human sexuality. The complete addresses were later compiled and expanded upon in many of John Paul's encyclicals, letters, and exhortations. In "Theology of the Body", John Paul II intends to establish an adequate anthropology in which the human body reveals God. He examines man and woman before the Fall, after