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 part of longstanding Church tradition — a tradition that was created in the context of scriptural teachings. The ability of the human body to express "truth" through the sexual union of married couples is acclaimed. The moral wrongness of using artificial means to manipulate such a significant aspect of the created body is explained. Dominion over outside forces, and also self-mastery through discipline, are integral human drives. However, the language expressed by bodies, in this context the language expressed during sexual intercourse, is so damaged by the use of artificial contraception that the conjugal act ""ceases to be an act