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
Catholic theology of the body dominating all subordinate material instincts, becomes similar to God. This similarity must be goal of all human undertaking. Gregory of Nazianzus (330-390) contemplated on the origin of the human body. Man was created by God with body and soul, a visible and invisible part, like the angels. He was created to praise God like they did. The body was given to man, so he may suffer and eventually die, and thus not consider himself to be God. The material essence of the body separates us from God, like a cloud, or, as Gregory stated, like the cloud between the Egyptians