Block · one region of the page, as the scanner read it. It may hold a whole story, part of one, several, or an advertisement; stitching blocks into articles is the next step. Text is supplied OCR.
Page 12 · column 2 of 6 · from the scan, no model involved
larity of the human heartbeat depends on calcium. Adequate levels of ionized calcium must be present in the cells of the heart muscle to prevent it from going into uncontrollable contractions or spasms.
Without calcium individuals could not jog, swim, play tennis, or any other physical activity. Calcium in the fluid surrounding muscle tissues regulates contractions of the muscle; other minerals in the fluid promote relaxation.
Because muscles, including the heart and diaphram, have to contract to work, every muscular action - from lifting your arm to breathing
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