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
The Human Body (TV series) July 2001 and includes a 50-minute feature on "The Making of the Human Body" - A final overview that reveals the techniques and developments that made the series possible. The series was adapted into a film released for IMAX cinemas. The film won the Giant Screen Theatre Association's Best Film For Lifelong Learning award. The book accompanying the series was written by Anthony Smith. According to one review, "Smith transcends anatomical trivia to record our bodies' powerful tale with empathy and clarity." The Human Body (TV series) The Human Body is a seven-part documentary series, first shown on 20 May