Do ?ó môi ch?t b? tác ??ng và d?ch chuy?n t?o thành dòng ch?y liên t?c qua bu?ng b?m. Thay ??i t?c ?? c?a màng b?m s? ?i?u ch?nh ???c l?u l??ng c?a b?m ?i?n t?.The diaphragm is actually a barrier among the thoracic and abdominal cavities, preventing abdominal organs from protruding in to the chest cavity. It performs a vital job in preservi