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
History of beliefs about the human body much on discourse about bodies, rather than on material bodies themselves. Drawing on Mikhail Bakhtin's 1965 "Rabelais and His World", they promoted a more materially orientated direction in the history of the body. The Ebers Papyrus is an Egyptian medical text and is the oldest known record of the human body, dating back to 3000 BC. The Ebers Papyrus describes the body by physical examination and what can be felt. Clinical investigations such as the Pulse, percussion of the body, the recognition of diseased or disordered states. “If thou examinst a swelling of the covering of his belly’s horns above