The most primitive precursor in the granulocytic series, having fine, evenly distributed chromatin, several nucleoli, a high nuclear-to-cytoplasmic ration (5:1-7:1), and a nongranular basophilic cytoplasm. They reside in the bone marrow. [ https://www.worldcat.org/search?q=bn%3A0721601464 GOC:add http://en.wikipedia.org/wiki/Myeloblast http://www.cap.org ]